Lesson 5

Test patch cords by substitution with a _________________________ one. If the problem is not caused by the patch cord and you can rule out configuration errors, you need to start testing the structured links. There are a number of network cabling and infrastructure troubleshooting devices to assist with this process.

"Known good"

How does NAPT work?

-Allocates each new connection a high-level TCP or UDP port. two hosts (10.0.0.101 and 10.0.0.103) initiate a web connection at same time, both requesting a response on the client (source) port 1024. -NAPT creates 2 new client port mappigns for the requests (10.0.0.101:60101 and 10.0.0.103:60103) It then substitutes the private source IPs for a single public source IP (217.45.253.5) and forwards the requests to the public Internet. It performs a reverse mapping on any traffic returned to those client ports, inserting the original private IP address and client port number, and forwarding the packets to the internal hosts. BOOOM

Identifying and correcting errors at this point will be much simpler than when you are trying to set up end user devices. When troubleshooting a cabled network link, you may need to consider:

-The patch cord between the PC and the wall port. -The wall port and the cabling in the wall. -The port on the patch panel and the patch cord to the switch port.

802.11a/b/g considered legacy standards, what else?

-limited to old equipment -•Both worked at 2.4 GHz; 802.11b WLANs upgraded to 802.11G •802.11b/g were more successful -As 802.11b and g both worked at 2.4 GHz, 802.11g provided an upgrade path for 802.11b WLANs. Working in the 5 GHz band, 802.11a is incompatible with the other two and was not as widely adopted.

Basic Rate Interface (BRI)

-provides two 64 Kbps "B" channels for data and one 16 Kbps "D" channel for link management control signals. -It is sometimes called 2B+D. One option is to use one B channel for data and leave the other for voice or fax; another is to provide a 128 Kbps link by concatenating the two B channels. This form of ISDN is intended for SOHO use.

Coax installations also-

-use screw-down F-connectors. A broadband cable service, for example, is likely to use the F-connector for drop cables.

step 3

1.SMTP delivers message; usually several "hops."

There are four broad "types" of Ethernet:

10 Mbps (10BASE-)—this is the original standard, specifying cabling and connectors for copper wire and fiber optic products. Fast Ethernet (100BASE-)—copper wire and fiber optic implementations of 100 Mbps LANs. Gigabit Ethernet (1000BASE-)—1000 Mbps LANs. This has replaced Fast Ethernet as the "standard" for a typical LAN. 10G Ethernet (10GBASE-)—10 Gbps links for LANs and WANs, mostly using fiber optic media. 10G Ethernet is widely used in data centers.

IPv4 Address Format In its raw form it appears as:

11000110001010010001000000001001

two most common frequency bands in the IEEE 802.11 standards:

2.4 GHz and 5.0 GHz.

The 5 GHz band is subdivided into ______ non-overlapping channels each _______ MHz-wide.

23 20MHz

Wireless Frequencies and Channels The range of broadcast radio frequencies (RF) extends from-

3 KHz to 300 GHz.

Bridges only came with up to ________ ports

4 ports.

A single switch might have up to _______ Ports and ____________ switches can be connected to create a switched fabric with thousands of ports.

48 multiple

Initially there were 11 channels in the 5 GHz band, but the subsequent _________ standard added another ________.

802.11h 12

RJ-45 connectors are also referred to as-

8P8C, standing for 8-position/8-contact.

Enterprise LAN

A larger network with hundreds or thousands of servers and clients. Such networks would require multiple enterprise-class switch, access point, and router appliances to maintain performance levels.

SME (Small and Medium Sized Enterprise)

A network supporting tens of users. Such networks would use structured cabling and multiple switches, access points, and routers to provide connectivity.

There are two classes of ISDN:

Basic Rate Interface (BRI) Primary Rate Interface (PRI)

Broadband VS Analog dialup

Broadband covers a range of different connection technologies. The main characteristics are that they are "always-on" (that is, the connection does not need to be re-established for each session) and data transfer rates are (a lot) higher than analog dial-up.

What is Email?

Email is a messaging system that can be used to transmit text messages and binary file attachments encoded using-

More than one BSS can be grouped together in an-

Extended Service Set (ESS).

What are FQDNs?

FQDNs reflect the hierarchy, from most specific (the host) to least specific (the top level domain followed by the root). For example: www.widget.com.

Example of this

Figure: URL with 1) Protocol; 2) FQDN; 3) File path

How do ports work?

For example, a client may contact an HTTP server at IP address 77.72.206.10 on port 80 (77.72.206.10:80). The HTTP server would respond to the client on a temporary (or ephemeral) port number that the client has opened for that purpose (47747, for instance).

Cat 5e (Enhanced Category 5)

Freq: 100 Mhz Capacity: 1 Gbps Max Distance:100m (328ft) Network Application: 1000BASE-T

For 2G, there were two competing formats, established in different markets:

Global System for Mobile Communication (GSM)-based phones. TIA/EIA IS-95 (cdmaOne)-based handsets.

Radio spectrum use regulated by? Standardized by who?

Governments International Telecommunications Union (ITU).

What are the ephemeral port ranges?

IANA defines the ephemeral port range as 49152 to 65535, but some operating systems use different values.

When talking about "wireless networking" for desktops, laptops, smartphones, and tablets, the term is generally understood to mean the-

IEEE's 802.11 standards for Wireless LANs (WLANs), also called Wi-Fi.

ISDN is a dial-up service billed for

ISDN is a dial-up service billed for

Internet access is then a question of how you join your local network to the-

ISP's PoP.

Destination IP address

Identifies the destination of the datagram by IP address.

2G overlook

In both cases, the cell network was built primarily to support voice calls, so 2G data access was provided on top, using Circuit Switched Data (CSD). CSD is somewhat similar to a dial-up modem, though no analog transmissions are involved. CSD requires a data connection to be established to the base station (incurring call charges) and is only capable of around 14.4 Kbps at best.

Network: def:

In its most simple form, a network consists of two or more computers connected to each other by an appropriate transmission medium which allows them to share data.

Protocol

Indicates whether the data should be passed to UDP or TCP at the destination host.

What would use UDP?

It may be used for applications that transfer time-sensitive data but do not require complete reliability, such as voice or video. The reduced overhead means that delivery is faster.

(Wifi Standards) 802.11ac (2013)

Maximum Transfer Rate: 1.7 Gbps (at time of writing) Band:5 GHz

using what?

Multipurpose Internet Mail Extensions (MIME).

General purpose (non-plenum) cabling uses-

PVC (polyvinyl chloride) jackets and insulation.

The concept of a _________ _____ ________ has gained some currency with the profusion of wireless and cellular connection technologies in the last few years.

Personal Area Network (PAN)

Most SOHO Internet access methods makes use of the-

Public Switched Telephone Network (PSTN).

IPv4 Packet Structure: 5 fields

Source IP address Destination IP address Protocol Checksum Time to Live (TTL)

Peer to peer connections are more likely to be implemented with ________________. What is the advantage?

Such peer-to-peer connections are now more likely to be implemented as Wi-Fi Direct, which has the advantage of automatically configuring a secure link between the stations.

Gigabit Ethernet can only run using-

Switches

What is the modern device used to reduce the effect of contention on the network?

Switches

T or F: Powering devices through PoE is more efficient than using a wall-socket AC adapter for each appliance

T

The domain name

The domain name identifies a company, organization, or even an individual. The name has to be unique and officially registered (a process that is normally handled by your ISP).

Elements of a URL

The protocol describes the access method or service type being used. The host location is usually represented by a Fully Qualified Domain Name (FQDN). The FQDN is not case sensitive. The host location can also be an IP address; an IPv6 address must be enclosed in square brackets. The file path specifies the directory and file name location of the resource (if required). The file path may or may not be case-sensitive, depending on how the server is configured.

•Internet access provided for private-address hosts through:

Through a router configured with a single or block of valid public addresses; the router translates between the private and public addresses using Network Address Translation (NAT). Through a proxy server that fulfills requests for Internet resources on behalf of clients.

Frequencies are subdivided into bands such as very low and ultra high. FM radio and television signals are broadcast in the-

Very High Frequency (VHF) band (30-300 MHz).

The term Campus Area Network (CAN) is sometimes used for-

a LAN that spans multiple nearby buildings.

Enabling and disabling ports is an important part of configuring-

a firewall, to ensure that only valid application protocols are allowed.

One basic distinction between types of network is between Local Area Networks (LANs) and Wide Area Networks (WANs). A LAN is-

a self-contained network that spans a small area, such as a single building, floor, or room.

Stations can also be configured to connect directly to one another. With older network standards, this is referred to as-

ad-hoc mode.

he 802.11s standard defines a Wireless Mesh Network (WMN). Unlike an ad hoc network, nodes in a WMN (called mesh stations)

are capable of discovering one another and peering, forming a Mesh Basic Service Set (MBSS).

IPv4 Address and Subnet Mask An IPv4 address and subnet mask can be set manually (static address). The IP address is entered as four decimal numbers separated by periods (e.g., 172.30.15.12). The IP address identifies-

both the network to which the interface is attached and also its unique identity on that network. An interface must be configured with an IP address.

If the plenum space is used for heating, there may also be higher temperatures. Therefore,

building regulations require the use of fire-retardant plenum cable in such spaces.

In a LAN, all the nodes or hosts participating in the network are directly connected with-

cables or short-range wireless media. A LAN is typically a single site or possibly several sites in close proximity connected by high-speed backbones.

NIC LED Status Diodes Network adapters typically have one or more Light Emitting Diode (LED) status lights that-

can provide information on the state of the network connection.

Wi-Fi requires bandwidth of approximately 20 MHz, not 5 MHz. Consequently, a site designer needs to-

choose the channels that do not overlap.

Each host must be configured with an IP address and subnet mask at a minimum in order to-

communicate on an IPv4 network. This minimum configuration will not prove very usable, however. Several other parameters must be configured for a host to make full use of a modern network or the Internet.

A second patch cord is used between the-

computer's network adapter and the wall port. This use of patch cords, permanent links, and patch panels is referred to as a structured cabling system.

All onboard cards support-

copper-based Ethernet with RJ-45 ports. You might use an add-in card to support other types of Ethernet, notably fiber optic.

6A is an improved specification cable with the ability to support 10 Gbps over 100 m. It is mostly deployed in-

data centers or as backbone cabling between servers and network appliances.

Like an Ethernet card, a Wi-Fi adapter is identified at the-

data link layer by a MAC address.

What are Private Addresses and where are they allowed?

defined by RFC 1918 and are sometimes referred to as RFC 1918 addresses. These are restricted to private LANs only.

An access point or adapter that can support both is referred to as

dual band. 2.4 GHz and 5 GHz bands simultaneously.

PoE-enabled switches are referred to as-

end-span (or end-point) Power Sourcing Equipment (PSE).

The multiple ports can be bonded to create a-

higher speed link. Four Gigabit Ethernet ports could be bonded to give a nominal link speed of 4 Gbps.

A hub is an early (legacy) type of device used to-

implement the Ethernet cabling design, referred to as a star topology.

Records traced from root down; each level of server has-

information about servers below in hierarchy.

Most Wi-Fi networks are configured in what is technically referred to as-

infrastructure mode.

Plenum space is an effective conduit for fire, as there-

is plenty of airflow and no fire breaks, such as walls and doors.

The best time to verify wiring installation and termination is-

just after you have made all the connections. This means you should still have access to the cable runs.

Inventory management refers to-

keeping a record of the systems running on your network. This is not a simple task to try to perform manually, so a number of protocols have been developed to assist.

Much of the switching technology of ISDN remains in use in terms of the telecommunications core network, but as an Internet access method for subscribers, it has-

largely been superseded by DSL and cable. It remains a good solution outside metropolitan areas where these other services may not be available.

Shielded Twisted Pair (STP) When twisted pair cabling was first used in networks based on IBM's Token Ring product, it was usually shielded to make it-

less susceptible to interference and crosstalk. Each pair was surrounded by a braided shield. This cable construction is referred to as Shielded Twisted Pair (STP).

In effect, the switch establishes a point-to-point link called a virtual circuit between any two network nodes. This is referred to as-

microsegmentation.

Twisted pair cabling for Ethernet is terminated using-

modular RJ-45 connectors.

802.3at (PoE+)

powered devices can draw up to about 25 W. PoE+ allows for a broader range of devices to be powered such as cameras with pan/tilt/zoom capabilities, door controllers, and thin client computers.

The network technology is what connects the computers, but the purpose of the network is to-

provide services or resources to its users.

The top of the DNS hierarchy is known as the:

root-level domain. often respresented by a (.)

If the masked portion does not match, IP assumes the packet must be-

routed to another IP network. For example:

SSL/TLS One of the critical problems for the provision of early e-commerce sites was the lack of-

security in HTTP.

How are these ports assigned?

server port numbers are assigned by the Internet Assigned Numbers Authority (IANA).

Historically, these services have included access to-

shared files, folders, and printers plus email and database applications.

Solid cabling uses a-

single thick wire for each conductor.

These trunks and IXPs are mostly created by-

telecommunications companies and academic institutions. -They are typically organized on national and international levels.

A normal—or straight through—Ethernet cable is wired with the same type of-

termination at both ends. Using T568A at one end and T568B at the other creates a crossover cable. Crossover cables were once used to connect computers directly, but Gigabit Ethernet interfaces can perform the crossover automatically, even if standard cable is used.

While a LAN is self-contained, that does not mean -

that it has to be small. LANs can range from networks with three or four nodes to networks with thousands of nodes. We are going to focus on two particular classes of LAN: SOHO and enterprise.

There are however, unregulated frequencies—Industrial, Scientific, and Medical (ISM) bands—that do not require a license, such as-

the 2.4 GHz and 5 GHz bands. The wireless networking products operate in these unregulated ultra high frequencies. There is a limit on power output, which means range is restricted.

Many subnetting schemes use one of-

the default masks.

An unmanaged switch performs-

the microsegmentation function described previously without requiring any sort of configuration. You just power it on, connect some hosts to it, and it works without any more intervention.

For most wireless networks, however, absolute range is less important than-

the number of clients that have to be supported and the construction of walls and ceilings.

Country codes are generally managed by an organization appointed by-

the relevant government.

Information about a domain is found by-

tracing records from the root down through the hierarchy. The root servers have complete information about the top level domain servers.

Plenum-rated cable uses-

treated PVC or Fluorinated Ethylene Polymer (FEP). This can make the cable less flexible but the different materials used have no effect on bandwidth.

Coax cabling is also available with-

tri- or quad-shielding for better resistance to EMI and eavesdropping.

•NAT address pool itself will be limited; multiple private addresses will use a single public address.

true

Coax suffers less from attenuation than-

twisted pair but is generally bulkier and more difficult to install.

The access point will be joined to the network in much the same way as a host computer is—

via a wall port and cabling to an Ethernet switch.

Recursive resolver

when a client application wants to resolve a name or FQDN, it uses a recursive resolver to perform the query. The resolver contacts name servers in the DNS hierarchy until it either locates the requested record or times out. When you configure a DNS server on a client, it is usually the address of a resolver that you are entering. A DNS server is usually configured to listen for queries on UDP port 53.

Network Address Translation: Most hosts on private networks are not configured with IP addresses that can communicate directly to the Internet. Instead-

when clients on the local network connect via a router, the router converts the client's private IP address into a valid public address using Network Address Translation (NAT).

F/UTP

with a foil screen around all pairs, often also designated ScTP.

Protocols at the transport layer, one up from the network layer, are concerned with-

with effective delivery. At the transport layer, the content of the packets starts to become significant.

•Range:2.4 GHz band

•2.4 GHz: maximum indoor range ~30-45 m (100-150 ft).

•Static addressing:

•Administrator manually configures each host. •Must update manually if host changes subnet. •Must track address allocations to avoid duplication. •Can be time consuming and error-prone. •Only used for systems with dedicated functionality.

Home and business networks use ISP to connect to Internet. What are the options?

•Dial-up, broadband (DSL, FTTx, cable), wireless connections.

Routers

•Switches use MAC addresses; routers use logical network and host IDs. Everything connected to an unmanaged switch is part of the same physical and logical network. When you want to connect such a network to the Internet or when you want to divide a large local network into logical subnetworks, you need to use one or more routers.

Route/path to destination is selected either-

•dynamically or statically; packet moves by hops along path to target. Once it has reached the destination network, the hardware address can be used to move the packet to the target node. This process requires each logically separate network to have a unique network address.

What is Wireless Networking?

"Wireless" encompasses a whole range of connectivity products and technologies, from personal area networking to Internet connectivity. Most wireless technologies use radio waves as transmission media. Radio systems use transmission and reception antennas tuned to a specific frequency for the transfer of signals.

Solid cable is used for-

"permanent" links, such as cable running through walls. This is often also called drop cable, as the installer drops the cable through the wall void to the hole cut out for the port.

As an Ethernet LAN media product _______________ and ________________________, coax could support 10 Mbps with cable lengths of up to 500 m and 185 m, respectively.

(10BASE-5/Thicknet and 10BASE-2/Thinnet)

Each conductor in 4-pair Ethernet cable is color-coded. Each pair is assigned a color-

(Blue, Orange, Green, or Brown).

IEEE 802.11:

-can deliver even more bandwidth with the option to use two adjacent 20 MHz channels as a single 40 MHz channel (channel bonding). •Can use 2.4 GHz or 5 GHz band (preferred). •Can use channel bonding in 5 GHz band to deliver more bandwidth. •Nominal data rates 288.8 Mbps (single channel) and 600 Mbps (bonded channels).

Therefore, theoretically an IPv4 address may be any value between-

0.0.0.0 and 255.255.255.255. However, some addresses are not permitted or are reserved for special use.

How does Microsegmentation work?

1) Computer A transmits a frame intended for Computer 2) The switch receives the frame into a port buffer and reads the destination MAC address from the Ethernet frame. 3)The switch uses its MAC address table to look up the port connected to the destination MAC address. 4)The switch uses its high speed backplane (an electrical connector that joins several electrical circuits together) to send the frame out on port 3 for computer B to receive. 5)None of the other connected devices, such as host C, observe any activity on the network while this process takes place. Therefore, these other devices are able to transmit and receive at the same time.

On a WLAN where only the first 11 channels are available, channels _____, ____< and ________ can be selected as non-overlapping.

1, 6, 11

basic function of TLS: 3 things

1.A server is assigned a digital certificate by some trusted Certificate Authority. 2.The certificate proves the identity of the server (assuming that the client trusts the Certificate Authority). 3.The server uses the digital certificate and the SSL/TLS protocol to encrypt communications between it and the client. This means that the communications cannot be read or changed by a third party.

What are the three private address ranges for Private Addresses?

10.0.0.0 to 10.255.255.255 (Class A private address range). 172.16.0.0 to 172.31.255.255 (Class B private address range). 192.168.0.0 to 192.168.255.255 (Class C private address range). Again here is APIPA 169.254.0.0 to 169.254.255.255 (APIPA/link-local autoconfiguration). As discussed earlier, this range is used by hosts for autoconfiguration when a DHCP server cannot be contacted (selecting a link-local address).

A Gigabit Ethernet link using twisted pair cabling can be up to-

100 m (328 feet) long. This means there must be no more than 100 m of cabling between the switch and the computer.

Channels The 2.4 GHz band is subdivided into up to-

14 channels, spaced at 5 MHz intervals from 2412 MHz up

Cheaper adapters may only support the-

2.4 GHz band. Many smartphone models only support 2.4 GHz.

2001:0db8:0000:0000:0abc:0000:def0:1234 is a IPv6 IP address, simplify this.

2001:0db8:0000:0000:0abc:0000:def0:1234 Even this is quite cumbersome, so where a double-byte contains leading zeros, they can be ignored. In addition, one contiguous series of zeroes can be replaced by a double colon place marker. Thus, the address above would become: 2001:db8::abc:0:def0:1234

if all the bits in an octet are set to 1, the number obtained is-

255 (the maximum possible value). Similarly, if all the bits are set to 0, the number obtained is 0 (the minimum possible value).

IPv4 Address Format An IPv4 address is how long?

32 bits long and is used within an IPv4 packet to define the source and destination of the packet.

The hub contains a number of ports—typically between

4 and 48—to provide connections for network devices.

how many ports on unmanaged switches in small networks?

4-8 ports

5 GHz:

5 GHz is less effective at penetrating solid surfaces and so does not support the maximum ranges achieved with 2.4 GHz standards. Nonetheless, the band supports more individual channels and suffers less from congestion and interference, meaning it supports higher data rates.

Most Cat _____________ cable is available in shielded variants, notably _________________

5e/6/6A F/UTP and U/FTP:

How are Distinguished Name and Relative Distinguished Name, used in the directory

A Distinguished Name is a unique identifier for any given resource within the directory. A distinguished name is made up of attribute-value pairs, separated by commas. Examples of attributes include Common Name (CN), Organizational Unit (OU), and Domain Component (DC). The most specific attribute is listed first and successive attributes become progressively broader. This most specific attribute is also referred to as the Relative Distinguished Name, as it uniquely identifies the object within the context of successive (parent) attribute values.

What is a VPN?

A VPN is a "tunnel" through the Internet (or any other public network). It uses special connection protocols and encryption technology to ensure that the tunnel is secure and the user is properly authenticated. Once the connection has been established, to all intents and purposes, the remote computer becomes part of the local network (though it is still restricted by the bandwidth available over the WAN link).

Satellite Internet Access

A Very Small Aperture Terminal (VSAT) microwave antenna is aligned to an orbital satellite that can either relay signals between sites directly or via another satellite. Satellites use frequency bands in the Super High Frequency range (3-30 GHz). •Satellite television receivers for domestic use; use growing for businesses, especially rural. •Transfer rates vary: 6 Mbps / 15-20 Mbps down typical. •Can be severe latency problems. could involve a 1000 ms delay. Dish at customer aligned with satellite; The antenna is connected via coaxial cabling to a DVB-S (Digital Video Broadcast Satellite) modem. This can be installed in the PC as an adapter card or as an external box connected via a USB or Ethernet port.

Connector types:Straight Tip (ST)

A bayonet-style connector that uses a push-and-twist locking mechanism; used mostly for multi-mode networks.

Hybrid Fiber Coax (HFC)/Cable

A cable Internet connection is usually available along with a Cable Access TV (CATV) service. These networks are often described as Hybrid Fiber Coax (HFC) as they combine a fiber optic core network with coax links to customer premises equipment, but are more simply just described as "broadband cable" or just as "cable."

Network Adapter/Network Interface Card (NIC)

A card that enables devices to connect to a network

Protocol Suite

A collection of several protocols used for networking are designed to work together.

Loopback Plugs

A loopback plug is used to test a port. It involves connecting pin 1 to pin 3 and pin 2 to pin 6. You can do this either by rewiring the jack or twisting the relevant pairs together on a cable stub. Alternatively, you can purchase a prefabricated loopback plug. When you connect a loopback plug to a port, you should see a solid connection LED. You can also use the plug in conjunction with diagnostic software.

Connector types:Lucent or Local Connector (LC)

A small form factor connector with a tabbed push/pull design. LC is similar to SC but the smaller size allows for higher port density.

•Access points can forward frames in a Wireless Distribution System (WDS), how?

Access Points can also be configured to forward frames between one another, functioning in a Wireless Distribution System (WDS) to extend the network without using a cabled backbone. A WDS can be configured in bridge mode, where the access points only forward communications between one another, and repeater mode, where they also communicate with stations. •Can be complex; can be compatibility issues with different vendors' devices.

4 components of a SOHO

Access point—allows clients with wireless radio adapters to connect to the network. Ethernet switch—connects wired client devices and printers with RJ-45 cables. Internet modem—interfaces with the physical link to the ISP's routers (DSL or cable, for instance). Internet router—forwards communications to and from the Internet Service Provider (ISP) routers to provide Internet access.

5G

According to the original specification, a 4G service was supposed to deliver 1 Gbps for stationary or slow-moving users (including pedestrians) and 100 Mbps for access from a fast-moving vehicle. Those data rates are now the minimum hoped-for standards for 5G, which is being rolled out for widespread use.

Server Message Block (SMB) is-

Also referred to as Common Internet File System (CIFS), •Underpins file and printer sharing on Windows networks; currently SMB2, but legacy clients are supported. •TCP port 445; also NetBIOS over TCP/IP (UDP and TCP port range 137-139). •Implemented as Samba on Linux.

IPv6 Addressing Schemes

An IPv6 address is divided into two main parts: the first 64 bits are used as a network ID, while the second 64 bits designate a specific interface. •Fixed size = no subnet mask; /nn = length of routing prefix in bits

Internet email addresses follow the mailto URL scheme. what is that?

An Internet email address comprises two parts—the username (local part) and the domain name, separated by an @ symbol. The domain name may refer to a company or an ISP; for example, [email protected] or [email protected].

Intrusion Protection System (IPS)

An Intrusion Protection System (IPS) adds some sort of real-time blocking (or shunning) functionality on top of the basic IDS. An IPS may drop packets, reset connections, or run a script to trigger a response on another server or network device (firewall, switch, or router).

Plenum:

An air handling space, including ducts and other parts of the HVAC system in a building.

Node

Any system or device connected to a network is also called a node. For example, if a network connects a file server, five computers, and two printers, there are eight nodes on the network. Each device on the network has a network address, such as a MAC address, which uniquely identifies each device. This helps keep track of where data is being transferred to and from on the network.

________________________________________________________________________connectors are crimped to the ends of the cable. The impedance of the connector must match the cable type ____________________________

BNC (alternately Bayonet-Neill-Concelman, British Naval Connector, or Barrel Nut Connector) (50 or 75 ohm).

The MAC address of the AP is used as-

Basic Service Set Identifier (BSSID).

Collisions only affect what kind of duplex? and where does the collision occur on a switch if a hub/legacy network card is attached to a pc?

Because each port is in a separate collision domain, collisions can only occur if the port is operating in half-duplex mode. Collisions only affect the segment between the port and that adapter—they do not slow down the whole network. For other devices, the network appears free, so they are able to send communications at the same time using the full bandwidth of the network media.

Coax is considered obsolete in terms of LAN applications but is still widely used for-

CCTV networks and as drop cables for cable TV (CATV) and Internet access, where it can support higher bandwidths but at reduced range.

General purpose cables are marked-

CMG/MMG or CM/MP.

Data cable rated for plenum use under the US National Electrical Code (NEC) is marked-

CMP/MMP.

The cable modem is interfaced to the local network or computer through an Ethernet adapter and with the cable network by a short segment of coax. More coax then links all the premises in a street with a ________ ________ ______ _______, which routes data traffic via the fiber backbone to the ISP's ________ ________ ____________) and from there to the Internet.

Cable Modem Termination System (CMTS) Point of Presence (PoP)

Note: Cabling is not the only part of the wiring system that must be rated to the appropriate category. For faster network applications (Gigabit Ethernet and better), the performance of connectors becomes increasingly critical. For example, if you are installing Cat 6A wiring, you must also install-

Cat 6A patch panels, wall plates, and connectors.

The number of twists is one factor in determining the speed and transmission limitations of the cable. Twisted pair cable is rated for different Ethernet applications according to "Cat" specifications, defined in the TIA/EIA-568-C Commercial Building Telecommunications Cabling Standards.

Cat Standards

Each switch port is a separate ____________ Domain

Collision

Connector types:Subscriber Connector (SC)

Connector with a push/pull design that allows for simpler insertion and removal than fiber channel (FC) connector. There are simplex and duplex versions, though the duplex version is just two connectors clipped together. It can be used for single- or multi-mode.

DOCSIS: specs as well

Data-Over-Cable Service Interface Specification •Downlink up to 38 Mbps (North America) or 50 Mbps (Europe); and uplink up to 27 Mbps for both. •DOCSIS v3 allows multiplexed channels for higher bandwidth.

DSL

Digital Subscriber Line (DSL) uses the higher frequencies available in a copper telephone line as a communications channel. The use of a filter prevents the DSL signals from contaminating voice traffic. •Advanced modulation and echo cancelling enable high-bandwidth, full-duplex. •DSL "modem" connects to phone system (usually router/modem/AP appliance). •Phone line connects to DSL modem bank (DSLAM). DSL Access Multiplier (DSLAM).

DHCP and DNS Servers Authentication is just one part of providing network access. Hosts must also receive a suitable network configuration to be able to communicate on the network. DHCP and DNS are two of the services that facilitate this:

Dynamic Host Configuration Protocol (DHCP) servers assign IP address information to host automatically when they connect to the network. Domain Name System (DNS) servers allow users to access resources using host names and Fully Qualified Domain Names (FQDN) by resolving those names to IP addresses.

Media Access Control (MAC) Address

Each Ethernet network adapter port has a unique hardware or physical address known as the Media Access Control (MAC) address. MAC addresses provide the value used in a frame's source and destination address fields. A MAC address consists of 48 binary digits (6 bytes). This is typically represented as 12 digits of hexadecimal with colon or hyphen separators or no separators at all—for example, 00:60:8c:12:3a:bc or 00608c123abc.

Frames

Each frame is identified by a preamble sequence, which is basically a warning to the NIC to expect a new frame. A frame is formatted with control information in the form of header fields, each of a fixed size and presented in a fixed order. The most important fields are the destination and source addresses of the adapter to which the frame is being directed and the adapter from which it was sent. Other information (not shown in the following simplified figure) includes the frame length and network layer protocol identifier. Following these fields comes the payload. This is the data that is being transported over the network. It will normally consist of a network packet, such as an Internet Protocol (IP) packet, with its own headers and payload. Putting layers of packets within one another like this is called encapsulation. The frame finishes with a checksum. The receiving computer can calculate its own checksum and compare it to this value. If they do not match, the receiving host rejects the frame as damaged.

File Transfer Protocol (FTP)

Early TCP/IP protocol;allows a client to upload and download files from a remote server. Also, if you have existing files that you want to make available to remote users, FTP is a simple service to install and maintain. FTP is associated with the use of TCP port 21 to establish a connection and either TCP port 20 to transfer data in "active" mode or a server-assigned port in "passive" mode.

Cat 5

Freq: 100 Mhz Capacity: 100 Mbps Max Distance: 100m (328ft) Network Application: 100BASE-TX

Cat 6

Freq: 250 Mhz Capacity: 1 Gbps Max Distance:100m (328ft) Network Application: 1000BASE-T

Cat 6a (Augmented Category 6)

Freq: 500 MHz Capacity: 10 Gbps Max Distance: 100m Network Application: 10GBASE-T

Cat 6 ALSO CAN

Freq:250 Mhz Capacity: 10 Gbps Max Distance:100m (328ft) Network Application: 10GBASE-T

The full name of any host is called its-

Fully Qualified Domain Name (FQDN).

Global System for Mobile Communication (GSM)-based phones.

GSM allows subscribers to use a Subscriber Identity Module (SIM) card to use an unlocked handset with their chosen network provider. GSM is adopted internationally and by AT&T and T-Mobile in the US.

3G The transition from 2G to 3G saw various packet-switched technologies deployed to mobiles:

General Packet Radio Services/Enhanced Data Rates for GSM Evolution (GPRS/EDGE) is a precursor to 3G (2.5G) with GPRS offering up to about 48 Kbps and EDGE about 3-4 times that. Unlike CSD, GPRS and EDGE allow "always on" data connections, with usage billed by bandwidth consumption rather than connection time. Evolved High Speed Packet Access (HSPA+) is a 3G standard developed via several iterations from the Universal Mobile Telecommunications System (UMTS) used on GSM networks. HSPA+ nominally supports download speeds up to 168 Mbps and upload speeds up to 34 Mbps. HSPA+-based services are often marketed as 4G if the nominal data rate is better than about 20 Mbps. CDMA2000/Evolution Data Optimized (EV-DO) are the main 3G standards deployed by CDMA network providers. EV-DO can support a 3.1 Mbps downlink and 1.8 Mbps uplink. I DONT KNOW IF THIS IMPORTANT SLIDE WAS SHORT

Web Servers and HTTP/HTTPS

HTTP is usually used to serve HyperText Markup Language (HTML) web pages, which are plain text files with coded tags describing how the page should be formatted. The functionality of HTTP servers is often extended by support for scripting and programmable features (web applications).

Host names

Host names and local domains are specified within the organization (for example, to identify a server located in the sales department of a company). The www host name is a common alias to indicate that the resource is a web server.

The domain name system is operated by-

ICANN (icann.org), who also manage the generic top level domains.

Source IP address

Identifies the sender of the datagram (basic transfer unit associated with a packet-switched network) by IP address.

Infrastructure mode means that each client device (or station) is configured to connect to the network via an Access Point (AP).=

In 802.11 documentation, this is referred to as a Basic Service Set (BSS)

The kinds of problems that may occur during the delivery of the data are non-delivery and delivery in a damaged state. What happens after that?

In the first case, the lack of acknowledgement results in the retransmission of the data and, in the second case, a Negative Acknowledgement (NACK) forces retransmission. TCP is described as connection-oriented, because it ensures the reliability and sequencing of messages passing over the connection.

ISDN Vs Dialup

Integrated Services Digital Network (ISDN) is a digital circuit-switched technology for voice, video, and data (hence "integrated services"). ISDN makes use of existing copper telephone wiring, if the wiring is of sufficient quality. Unlike dial-up, however, it uses the line to transmit digital signatures for both voice and data. This means that there are no inefficient analog-to-digital conversions and so higher speeds can be supported.

Layer:Internet Protocol (IP)

Internet Protocol (IP)—provides packet addressing and routing at the network layer. IP provides best effort delivery of an unreliable and connectionless nature. A packet might be lost, delivered out of sequence, duplicated, or delayed.

Most home users and businesses rely on an____________________________ to facilitate the link between their SOHO network and the Internet.

Internet Service Provider (ISP)

The ___________ handles the business of allocating one or more public Internet Protocol (IP) addresses that will work on the Internet and other services, such as domain name registration, web and email hosting, and so on.

Internet Service Provider (ISP)

Internet Connections: The major infrastructure of the Internet, also referred to as the ________ __________, consists of very high bandwidth trunks connecting _________ ________ ________.

Internet backbone Internet eXchange Points (IXPs).

Routers; •Many different types and uses; two general tasks:

LAN router—divide a single physical network into multiple logical networks. This is useful for security and performance reasons. WAN or edge/border router—join a network using one type of media with a network using different media. A typical example is to join a LAN to a WAN, such as the Internet.

Hosts also have a "fallback" mechanism for when the computer is configured to use a DHCP server but cannot contact one. What is this?

Link Local Addressing/APIPA In this scenario, the computer selects an address at random from the range 169.254.1.0 to 169.254.254.255. Microsoft calls this Automatic Private IP Addressing (APIPA). When a host is using an APIPA address, it can communicate with other hosts on the same network that are using APIPA, but cannot reach other networks or communicate with hosts that have managed to obtain a valid DHCP lease.

4G Long Term Evolution (LTE) & LTE Advanced (LTE-A)

Long Term Evolution (LTE) is a converged 4G standard supported by all network providers. Any device using a 4G connection needs a SIM card. LTE has a maximum downlink of 150 Mbps in theory, but no provider networks can deliver that sort of speed at the time of writing. Around 20 Mbps is more typical of real-world performance. LTE Advanced (LTE-A) is intended to provide a 300 Mbps downlink, but again this aspiration is not matched by real-world performance. Current typical performance for LTE-A is around 40 Mbps.

(Wifi Standards) 802.11a (1999)

Maximum Transfer Rate: 54 Mbps Band:5 GHz

(Wifi Standards) 802.11b (1999)

Maximum Transfer Rate:11 Mbps Band:2.4 GHz

(Wifi Standards) 802.11n (2009)

Maximum Transfer Rate:288.8 Mbps/stream (Single Channel) 600 Mbps/stream (Bonded Channels) Band:2.4/5 GHz

(Wifi Standards) 802.11g (2003)

Maximum Transfer Rate:54 Mbps Band:2.4 GHz

The FTP client may take a number of forms: 3

Most installations of TCP/IP include a command-line client interface. The commands put and get are used to upload and download files, respectively. Dedicated GUI clients allow you to connect to servers, browse directories, and upload and download files. Internet browsers allow you to connect to an FTP service and download files. You use another type of URL(that starts with ftp://) to connect to an FTP server.

Communications are transported over an Ethernet cable by electrical signaling in the case of twisted pair, or light signaling in the case of fiber optic. The physical connection to the network media is made using a port in the computer's network adapter or-

Network Interface Card (NIC).

what is a Enterprise Network Architecture?

Networks supporting larger businesses or academic institutions use the same switch, access point, router, and modem functions as are present in SOHO networks, but because they must support more clients with a greater degree of reliability, each function is performed by a separate network device. You could think of these larger networks as falling into two categories:

TCP and UDP Ports

One of the critical functions of the transport layer is to identify each type of network application. It does this by assigning each application a port number between 0 and 65535. At the transport layer, on the sending host, data from the upper layers is packaged as a series of segments and each segment is tagged with the application's port number. The segment is then passed to the network layer for delivery. The host could be transmitting multiple HTTP and email segments at the same time. These are multiplexed using the port numbers onto the same network link.

In T568B, pin 1 is wired to-

Orange/White, pin 2 is wired to Orange, pin 3 is wired to Green/White, and pin 6 is wired to Green or, put another way, the orange and green pairs are swapped over.

Fiber to the Node (FTTN) Fiber to the Curb/Cabinet (FTTC). Explain

Other solutions can variously be described as Fiber to the Node (FTTN) or Fiber to the Curb/Cabinet (FTTC). These extend the fiber link to a communications cabinet in the street servicing multiple subscribers. This is a similar model to HFC, but instead of the coax segment, each subscriber is linked to the fiber service by running Very High Bitrate DSL (VDSL) over the existing telephone wiring.

Customers connect to an ISP's network via a local _______ _____________ ____________ The ISP uses a _____________________________ to connect each POP to their core network infrastructure and one or more IXPs.

Point of Presence (PoP) backhaul link (or a transit arrangement with another ISP)

Coax cables are categorized using the-

Radio Grade (RG) "standard." developed by US military, categorizes cable by thickness and impedance.

Uniform Resource Locator

Resources on the Internet are accessed using an addressing scheme known as a Uniform Resource Locator (URL). A URL contains all the information necessary to identify and access an item.

2 categories of a Enterprise Network Architecture

SME (Small and Medium Sized Enterprise) & Enterprise LAN

What was developed because of this?

Secure Sockets Layer (SSL) was developed by Netscape and released as version 3.0 in 1996 to address these problems. SSL proved very popular with the industry and is still in widespread use.

The ANSI/TIA/EIA 568 standard defines two methods for terminating RJ-45 connectors:

T568A and T568B.

Layer:Transport Layer (TCP/UDP Protocols)

TCP: guarantees orderly transmission of packets at the transport layer. TCP can identify and recover from lost or out-of-order packets. This is used by most TCP/IP application protocols as failing to receive a packet or processing it incorrectly can cause serious data errors. •UDP provides non-guaranteed packet transfer, but is faster

can also be used with

TLS can also be used with UDP applications, referred to as Datagram Transport Layer Security (DTLS). Some VPN solutions depend on the use of DTLS.

An ISDN connection would typically be facilitated through a-

Terminal Adapter (TA). The TA may be an external appliance or a plug-in card for a PC or compatible router. The TA is connected to the ISDN network via an NT1 device (Network Terminator). The ISDN-enabled router may then either be connected to a switch or support direct connections from ISDN devices.

IEEE 802.11ac

The 802.11ac standard continues the development of 802.11n technologies. the main distinction is that 802.11ac works only in the 5 GHz band. The 2.4 GHz band can be used for legacy standards (802.11b/g/n) in mixed mode. The aim for 802.11ac is to get throughput similar to that of Gigabit Ethernet or better. It supports more channel bonding (up to 80 or 160 MHz channels), up to 8 spatial streams rather than 4, and denser modulation (at close ranges). •Needs high-end equipment for sufficient antennas for 8 streams. The maximum theoretical data rate with 8 streams and 160 MHz channel bonding is about 6.93 Gbps.

Public Switched Telephone Network (PSTN)

The PSTN is the national and global telecommunications network. The voice-grade copper wire part of this network (between subscribers and the telecom provider's switches) is sometimes referred to as the Plain Old Telephone Service (POTS), "local loop," or "last mile."

Email can involve the use of multiple protocols. The following process illustrates how an email message is sent from a typical corporate mail gateway (using the Microsoft Exchange mail server) to a recipient with subscriber Internet access: Step 1!

The email client software on the sender's computer ([email protected]) sends the message to the Exchange email server using Microsoft's Message Application Programming Interface (MAPI) protocol. The mail server puts the message in a queue, waiting for the next Simple Mail Transfer Protocol (SMTP) session to be started. SMTP uses TCP port 25 by default.

A global address is one that is unique on the Internet (equivalent to public addresses in IPv4). Global unicast addresses have the following format:

The first 3 bits indicate that the address is within the global scope. In hex notation, a global unicast address will start with either "2" or "3." The next 45 bits are allocated in a hierarchical manner to regional registries and from them to ISPs and end users. The next 16 bits identify site-specific subnet addresses. The final 64 bits are the interface ID. The interface ID is either generated from the adapter's MAC address (padded with extra bits to make it 64 bits in length) or is randomly generated.

Fiber to the Premises (FTTP) Fiber to the Home (FTTH) Explain

The most expensive solution is Fiber to the Premises (FTTP) or its domestic variant Fiber to the Home (FTTH). The essential point about both these implementations is that the fiber link is terminated on customer premises equipment. Such "pure" fiber solutions are not widespread and generally carry a price premium above other types of Internet access.

Network and Host address explained

The network address is used to find the subnet in which the computer or the device is located and the host address is used to find the computer or the device in the subnet.

Time to Live (TTL)

The number of hops a datagram is allowed to stay on the network before being discarded, otherwise packets could endlessly loop around an internet. A router will decrease the TTL by at least one when it handles the packet.

Multimeter:

The primary purpose of a multimeter is for testing electrical circuits, but you can use one to test for the continuity of any sort of copper wire, the existence of a short, and the integrity of a terminator. To perform useful tests, you need to know the readings that are expected from a particular test. For example, if the resistance measured across UTP Ethernet cable is found to be 100 ohms, then the cable is OK, but if the resistance between the two ends of a cable is infinity, then the cable has a break •Wire map tester: identifies transpositions and reverse pairs. •Advanced testers: show cable's physical/electrical properties. •Certifiers: test and certify installation to a category.

Virtual LAN (VLAN)

The switches on an enterprise network can provide thousands of ports. It is inefficient to have that many connections to the same "logical" network. the ports are divided into groups using a feature of managed switches called Virtual LAN (VLAN) each VLAN is associated with a different logical subnetwork address Communications between different VLANs therefore have to go through a router. (this improves performance and security) Traffic passing between VLANs can be easily filtered and monitored to ensure it meets security policies.

default masks.:

These are masks comprising whole octets only. Each default mask is known by a particular "class."

Crimpers

These tools fix a jack to a cable. As with an IDC, the wires are laid in the appropriate terminals in the jack and the crimper tool then closes and seals the jack. The tools are specific to a particular type of connector and cable, though some may have modular dies to support a range of RJ-type jacks.

Punch-down tool

These tools fix conductors into an IDC. The wire pairs are untwisted and laid in the terminals in the IDC in the appropriate termination order (T568A or T568B). It is important not to untwist the pairs too much, however. The punch-down tool then presses the wire into the terminal, cutting through the insulation to make an electrical contact.

There are 13 root level servers (A to M), What lies below that?

Top Level Domains (TLDs). There are several types of top level domain, but the most prevalent are generic (.com, .org, .net, .info, .biz), sponsored (.gov, .edu), and country code (.uk, .ca, .de).

The transport layer is also responsible for ensuring reliable data delivery so that packets arrive error-free and without loss. The transport layer can overcome lack of reliability in the lower level protocols. This reliability is achieved by the

Transport Control Protocol (TCP) using acknowledgement messages that inform the sender the data was successfully received.

developed from SSL and ratified as a standard by IETF

Transport Layer Security (TLS) was developed from SSL and ratified as a standard by IETF. TLS is now the product in active development, with 1.2 as the latest version.

The most common uses of ISDN are for interconnection of-

Used to connect LANs and for remote workers

Checksum

Verifies the packet's integrity upon arrival at the destination.

___________ ______ ______ ________achieves higher bit rates at the expense of range. It allows for both symmetric and asymmetric modes. Over 300 m (1000 feet), an asymmetric link supports 52 Mbps downstream and 6 Mbps upstream, whereas a symmetric link supports 26 Mbps in both directions. VDSL2 also specifies a very short range (100 m/300 feet) rate of 100 Mbps (bi-directional).

Very High Bitrate DSL (VDSL)

NetBIOS/NetBT

Very earliest Windows network Used Network Basic Input/Output System (NetBIOS) NetBIOS allowed computers to address one another by name and establish sessions. As the TCP/IP suite became the standard for local networks, NetBIOS was re-engineered to work over the TCP and UDP protocols, referred to as NetBIOS over TCP/IP (NetBT): Name service (UDP port 137). Datagram transmission service (UDP port 138). Session service (TCP port 139). •Should be disabled unless supporting legacy Windows systems or appliances.

Of course, there are many more network communication types than email. Network services are equally likely to support-

Voice over IP, videoconferencing, messaging, and integration with social media.

Web server:

Web server: A server that provides client access using HTTP (defaults to port 80) or its secure version HTTPS (defaults to port 443).

Collision Domain

When Contention created within the hub-based ethernet causes transmissions to collide. All nodes within a hub are involved in the collision because all PCs connected to the hub receive all communications. A lot of the communications are unnecessary and a lot of them "collide." When there is a collision, all the nodes have to stop and resend frames, slowing the network down.

A _______________spans multiple geographic locations. __________ typically connect multiple LANs using ___________ transmission media.

Wide Area Network Long-Range Transmission Media

The IEEE 802.11 series of standards (Wi-Fi) are used to implement __________________________ so the technologies complement one another and are often used together in the same network.

Wireless Local Area Networks (WLAN)

TIA/EIA IS-95 (cdmaOne)-based handsets.

With Code Division Multiple Access (CDMA), the handset is managed by the provider, not the SIM. CDMA adoption is largely restricted to the telecom providers Sprint and Verizon.

Is a NIC also referred to as a network adapter?

Yes

•Networks have converged on use of TCP/IP protocol suite

Yes they have

Each domain name has to be registered with-

a Domain Name Registry for the appropriate top level domain.

An embedded system is

a computer system that is designed to perform a specific, dedicated function. •Range from individual microcontrollers to complex industrial control systems. •May have been designed for a closed network, without connectivity. •Special design and security considerations when interacting with a data network. •Risk for maintenance and troubleshooting; require specialist knowledge.

In IEEE 802.11 (Wi-Fi) terminology, a station (abbreviated as STA) is-

a device that has the capability to use the 802.11 protocol. For example, a station may be a laptop, a desktop PC, PDA, access point or Wi-Fi phone. An STA may be fixed, mobile or portable.

The Domain Name System (DNS) is:

a hierarchical system for resolving names to IP addresses. It uses a distributed database that contains information on domains and hosts within those domains. The information is distributed among many name servers, each of which holds part of the database. The distributed nature of the system has the twin advantages that maintenance of the system is delegated and loss of one DNS server does not prevent name resolution from being performed.

Describe PoE or Power over Ethernet

a means of supplying electrical power from a switch port over Cat 5 or better data cabling to a connected powered device, such as a tablet computer, VoIP handset, security camera, or wireless access point. PoE is defined in two IEEE standards

Organizations should try to avoid using-

a mixture of the two standards. It is difficult to say whether one is more prevalent than the other. T568A is mandated for US government premises and by the residential cabling standard (TIA 570).

Any application or process that uses TCP or UDP for its transport, such as HTTP for web services or POP3 for email, is assigned-

a unique identification number called a port.

The maximum range of an ADSL modem is typically-

about 10,000 feet (2 miles or 3 km), but the longer the connection, the greater the deterioration in data rate.

the second conductor has-

an insulator with the solid color.

The frequencies used by Wi-Fi lack penetrating power and there can be interference from nearby unregulated devices, such as-

baby monitors and cordless phones. Microwave ovens can also cause interference.

For the NIC to be able to transmit and receive the signals and process them as digital data, they must-

be divided into regular units with a consistent format. There must also be a means for each node on the local network to address communications to another node. Ethernet provides a data link protocol to perform these framing and addressing functions.

A SOHO (Small Office Home Office) LAN is a-

business-oriented network possibly using a centralized server in addition to client devices and printers, but often using a single Internet appliance to provide connectivity. Home and residential networks may also be classed as SOHO.

Metropolitan Area Networks The term Metropolitan Area Network (MAN) is sometimes used, though it doesn't really have a clear definition other than an area equivalent to a-

city or other municipality. It could mean a company with multiple connected networks within the same metropolitan area—so, larger than a LAN but smaller than a WAN.

A bridge can be used to divide an overloaded network into seperate-

collision domains.

Patch cords for fiber optic can come with the same-

connector on each end (ST-ST, for instance) or a mix of connectors (ST-SC, for instance).

A plenum space is a void in a building designed to carry Heating, Ventilation, and Air Conditioning (HVAC) systems. Plenum space is typically a false ceiling, though it could also be-

constructed as a raised floor. As it makes installation simpler, this space has also been used for communications wiring in some building designs.

When a device is connected to a port on a PoE switch, the switch goes through a-

detection phase to determine whether the device is PoE-enabled. If not, it does not supply power over the port and therefore does not damage non-PoE devices. If so, it determines the device's power consumption and sets the supply voltage level appropriately.

A repeater is a-

device used to overcome the distance limitations imposed by network cabling. It receives a transmission arriving over one cable segment and then regenerates and retransmits it at the original strength over another cable segment.

with PoE, It also allows network management software to control the-

devices and apply power schemes, such as making unused devices go into sleep states and power capping.

A PAN refers to using wireless connectivity to connect to-

devices within a few meters—printers, smartphones, headsets, speakers, video displays, and so on.

STP is bulky and-

difficult to install, so where a degree of protection from interference is required, modern twisted pair cabling installations use screened cables, meaning a shield positioned around all pairs. There are many different ways of designating different types of shielding.

A bridge is a device that-

divides a local network into two or more segments. Hosts on one segment are able to communicate with those on another segment only via the bridge.

11000110 00101001 00010000 00001001 to make IP addresses easier to use, they are usually displayed in -

dotted decimal notation. This notation requires each octet to be converted to a decimal value. The decimal numbers are separated using a period. Converting the previous number to this notation gives: 198 . 41 . 16 . 9

Infrastructure mode means that-

each client device (or station) is configured to connect to the network via an Access Point (AP).

Fiber optic connectors are quite-

easy to damage, and should not be repeatedly plugged in and unplugged.

Communications are transported over an Ethernet cable by-

electrical signaling in the case of twisted pair, or light signaling in the case of fiber optic.

•Organizations may lease from ISP; host directly; use private servers (intranets) theres one i left out

extranets (if they permit remote access).

Enterprise ISP solutions will offer much higher bandwidth links, often using-

fiber optic cabling.

In a Hybrid Fiber Coax (HFC) network, coax cable links the-

fiber optic trunk serving the whole street to the cable "modem" installed in the customer's premises.

Ethernet is a very ____________ technology. It can support a wide range of different types and sizes of __________

flexible, LAN

Wire Stripper/Cutter

for cutting wire and stripping insulation and cable jackets.

While a switch forwards frames using hardware (MAC) addresses within a single network segment, a router-

forwards packets around an internetwork using logical network and host IDs.

Multi-Mode Fiber (MMF)

has a larger core (62.5 or 50 microns) and is designed to carry a shorter wavelength light (850 nm or 1300 nm) transmitted in multiple waves of varying length. MMF uses less expensive optics and consequently is less expensive to deploy than SMF. However, it does not support such high signaling speeds or long distances as single-mode and so is more suitable for LANs than WANs

Single-Mode Fiber (SMF)

has a small core (8-10 microns) and is designed to carry a long wavelength, near infrared (1310 or 1550 nm) light signal, generated by a laser. Single-mode cables support data rates up to 10 Gbps or better and cable runs of many kilometers, depending on the quality of the cable and optics.

RG-6 cable:

has a thicker core conductor for better signal quality and is often used as a drop/patch cable for modern Cable Access TV (CATV) and broadband cable modems.

RG-59 cable

has a thinner core conductor and was used as a drop cable for older CATV/cable modem installs and is also used for CCTV cabling.

What is Management Information Base (MIB)

holds statistics relating to the activity of the device. An example of such a statistic is the number of frames per second handled by a switch. The agent is also capable of initiating a trap operation where it informs the management system of a notable event (port failure, for instance). The threshold for triggering traps can be set for each value.

in Solid Cabling, This cable links the RJ-45 port on a wall plate with a patch panel. Rather than using modular RJ-45 connectors, solid cable terminates-

in Insulation Displacement Connectors (IDC) at the back of the wall plate and patch panel.

Legacy STP cable could be more complex to install as it required bonding each element to ground manually but modern screened and shielded solutions (using appropriate cable, connectors, jacks, and patch panels) reduce this complexity by

incorporating grounding within the design of each element.

ach station in a Wi-Fi network needs to be installed with a Wi-Fi adapter supporting the 802.11 standard(s) used on the network. A Wi-Fi adapter can be-

installed if the function is not available on the motherboard. Both internally installed adapter cards and USB-connected adapters are available. A Wi-Fi card may also need to be installed to support the latest standard (upgrading from 802.11g to 802.11n or 802.11ac, for instance).

At the network and data link layers, the port number is not significant. Why?

it becomes part of the data payload and is "invisible" to routers and switches working at the network and data link layers. At the receiving host, each segment is extracted from its frame and then identified by its port number and passed up to the relevant handler at the application layer. Simultaneous segment transmissions are multiplexed onto network link; de-multiplexed at receiving host

Use of a frequency usually requires a __________ from the relevant government agency.

license; The license ensures no one else can transmit that frequency within a particular area.

Describe the lights on a network adapter and what they mean:

link lights: if the link light is not lit then there is generally a problem with the cable or the physical connection Activity light: Flickers when packets are received or sent. If the light flickers constantly, the network might be overused or there might be a device generating network noise. Some multi-speed adapters have a speed light to show whether the adapter is operating at 10 Mbps (Ethernet), 100 Mbps (Fast Ethernet), or 1000 Mbps (Gigabit Ethernet). Some types of equipment combine the functions of more than one light into dual-color LEDs. For example, a green flickering light might indicate normal activity, whereas an orange flickering light indicates network traffic collisions.

•Range:5 GHz

maximum indoor range up to ~30 m.

DHCP

may make a mistake with the address information—perhaps duplicating an existing IP address or entering the wrong subnet mask—or the configuration of the network may change, requiring the host to be manually configured with a new static address. To avoid these problems, a Dynamic Host Configuration Protocol (DHCP) Server can be used to allocate an IP address and subnet mask (plus other settings) dynamically.

The greater number of non-overlapping channels means that co-channel interference is less of a problem for the 5 GHz band. This means that-

more WLANs can occupy the same area or that you can provision more access points closer together to support a greater density of client devices.

There is also an unmanaged switch embedded in-

most of the Internet router/modems supplied by Internet Service Providers (ISP) to connect to their networks.

A router is responsible for-

moving data around a network of networks, known as an internetwork or internet.

The limited number of non-overlapping channels means that co-channel interference is a real possibility. Special codes embedded in the signal give each transmitting node a distinguishing pattern, so that-

nearby networks can share the same channel at once. At some point, however, the channel becomes saturated with too many WLANs.

Fiber Optic Cabling and Connectors: Copper wire carries electrical signals, which are subject to interference and attenuation. Light signals are

not susceptible to interference, cannot easily be intercepted (eavesdropped), and suffer less from attenuation. Consequently, fiber optic cabling can support much higher bandwidth, measured in multiple gigabits or terabits per second, and longer cable runs, measured in miles rather than feet.

11000110001010010001000000001001 The 32 bits are subdivided into four groups of 8 bits (1 byte) known as ______________ The above IP address could therefore be rearranged as:

octets. 11000110 00101001 00010000 00001001

Switch is appliance at core-

of modern networks.

Plenum cable must not emit large amounts-

of smoke when burned, be self-extinguishing, and meet other strict fire safety standards.

Where there is a binary 1 in the mask, the corresponding binary digit in the IP address is part-

of the network ID. The relative sizes of the network and host portions determines the number of networks and hosts per network a particular addressing scheme can support.

A legacy system is

one that is no longer directly supported by its vendor. •May be retained on networks to support existing services that are not practical to migrate. •Security risks. •Should be isolated from network. •Like embedded systems, risk for maintenance and troubleshooting; require specialist knowledge.

The mesh stations can perform ________ __________ and forwarding between peers, using a routing protocol such as the __________ ________ ______ ________

path discovery Hybrid Wireless Mesh Protocol (HWMP).

A modem works at the same level as a switch, making a-

physical network link with the ISP's network.

If an existing switch does not support PoE, a device called a __________ ___________ can be used.

power injector

802.3af PoE Standard

powered devices can draw up to about 13 W over the link. Power is supplied as 350mA@48V and limited to 15.4 W, but the voltage drop over the maximum 100 feet of cable results in usable power of around 13 W.

the first conductor in each pair has a-

predominantly white insulator with stripes of the color

Protocols are-

procedures or rules used by networked hosts to communicate. For communication to take place, the two hosts must have a protocol in common.

Primary Rate Interface (PRI)

provides 23 or 30 "B" channels (or between about 1.5 and 2 Mbps), depending on location in the world, and one 64 Kbps D channel. This form of ISDN is intended for larger companies and is commonly used to provide a link between two company locations.

Often service providers impose usage restrictions to limit the amount of data downloaded per month. Actual speed may be affected by-

quality of the cabling in the consumer's premises and between the premises and the exchange and also by the number of users connected to the same DSLAM (contention).

a range extender is a simpler device for-

regenerating a signal from an access point to a more remote location, such as an upstairs room. Another option is a range extender that works with a powerline adapter to communicate with the access point over the electrical wiring. can work with powerline adapter.

Fiber to the Curb (FTTC) For the telecommunications companies, the major obstacle to providing really high bandwidth to consumers and small businesses is in the last mile of the telephone network. Copper cabling infrastructure in the last mile is often of poor quality as it was only designed to-

service a telephone line. The projects to update this wiring to use fiber optic links are referred to by the umbrella term "Fiber to the X" (FTTx).

A hub simply ensures that all devices receive

signals put on the network, working as a multiport repeater.

The Apple Filing Protocol (AFP)

similiar to SMB but for apple AFP associated with 2 ports: -UDP or TCP port 427 •(Service Location Protocol)—not required by OS X or later. TCP Port 548-main port used by AFP

Fiber optic cables fall into two broad categories:

single-mode and multi-mode:

Asymmetrical DSL (ADSL) is a "consumer" version of DSL that provides a fast downlink but-

slow uplink.

When would we use UDP instead of TCP?

sometimes it is more important that communications be faster than they are reliable. The acknowledgements process of TCP adds a lot of overhead. he User Datagram Protocol (UDP) is: •Connectionless, non-guaranteed, no sequencing or flow control. •Speeds up communication by reducing overhead. •For applications that: •Don't require acknowledgement and can tolerate missing or out-of-order packets. •Are time-sensitive but don't need complete reliability.

HyperText Transfer Protocol (HTTP) is

the basis of the World Wide Web. HTTP enables clients (typically web browsers) to request resources from an HTTP server. A client connects to the HTTP server using its TCP port (the default is port 80) and submits a request for a resource, using a Uniform Resource Locator (URL).

How DHCP assigns IPs

the computer contacts the DHCP server as it starts up and is allocated a lease for an IP address. Settings such as default gateway and DNS server addresses may be passed to the computer at the same time. If the address information needs to change, this can be done on the DHCP server, and clients will update themselves automatically when they seek a new lease (or a new lease can be requested manually).

Unshielded Twisted Pair (UTP)

the type of cabling most widely used for computer networking. With the type of UTP used for Ethernet, the cable contains four copper conductor "pairs." Each conductor has an insulating sheath. Each pair of conductors is twisted, which reduces interference between the wires (crosstalk) and interference from other electromagnetic sources, referred to as Electromagnetic Interference (EMI).Each pair is twisted at a different rate to further reduce interference. The signals sent over each pair are balanced. This means that each wire carries an equal but opposite signal to its pair. This is another factor helping to identify the signal more strongly against any source of interference. The four pairs are covered by a protective outer jacket. The insulation sheaths and jacket are usually made of (PVC). UTP works well where there are no powerful interference sources, but the electrical signaling method has limited range. The signal is said to suffer from attenuation, meaning that it loses power quickly over long ranges (above 100 m).

What is the network # or ID?

this number is common to all hosts on the same IP network.

The host number (host ID)?

this unique number identifies a host on a particular IP network.

Different mail systems have different requirements for allowed and disallowed characters in the local part. The local part is supposed-

to be case-sensitive, but most mail systems do not treat it as such. An incorrectly addressed email will be returned with a message notifying that it was undeliverable. Mail may also be rejected if it is identified as spam or if there is some other problem with the user mailbox (such as the mailbox being full).

The purpose of a network is-

to make host services available.

A tone generator and probe tool is used-

to trace a cable from one end to the other. This may be necessary when the cables are bundled and have not been labeled properly. This device is also known as a "Fox and Hound" or "toner and probe." The tone generator is used to apply a signal on the cable. The probe is used to detect the signal and follow the cable over ceilings and through ducts or identify it from within the rest of the bundle. To locate a cable in a group of cables, connect the tone generator to the copper ends of the wires, then move the tone locator over the group of cables. A soft beeping tone indicates that you are close to the correct wire set; when the beeping is loudest, you have found the cable. Note: Do not connect a tone generator to a cable that is connected to a NIC. The signal sent by the tone generator can destroy network equipment.

Coaxial Cabling and Connectors: Coaxial, or coax cable is a different type of copper cabling, also carrying electrical signals. Where twisted pair uses balancing to cancel out interference, coax uses-

two conductors that share the same axis. The core signal conductor is enclosed by plastic insulation (dielectric) then a second wire mesh conductor serves both as shielding from EMI and as a ground.

Some cards support more than one type of connector. You can also purchase cards with multiple ports of the same type—

two or four Gigabit RJ-45 Ethernet ports, for instance.

The type of modem must be matched to the

type of link (dial-up, DSL, cable, and so on).

Under HTTP, all data is sent-

unencrypted and there is no authentication of client or server.

Note: Standalone repeater devices are still widely used. On fiber optic networks it is often necessary to-

use repeaters on long-distance communications cabling.

In effect, the switch establishes a point-to-point link called a

virtual circuit between any two network nodes.

The DSLAM channels-

voice and data traffic to the appropriate network. Depending on the equipment used by the ISP, the data link protocol used for DSL may be PPP over ATM (PPPoA) or PPP over Ethernet (PPPoE).

Modern networks are evolving to provide more diverse services, including-

web applications, social networking, Voice over IP, multimedia conferencing, and Internet of Things connectivity for household devices and appliances.

Configuration of a managed switch can either be performed over a-

web interface or some sort of command line. The picture is •Interface configuration on a Cisco switch

U/FTP

with foil shielding for each pair.

access point does what?

works as a bridge, forwarding communications between the wireless stations and the wired network, referred to as a Distribution System (DS).

ADSL2+: downlink rates up to- uplink rates?

~24 Mbps; uplink rates up to ~1.4 Mbps

VDSL ranges for all modes:

•Asymmetric: 52 Mpbs downstream/6 Mpbs upstream over 300 m/1000 ft •Symmetric: 26 Mbps in both directions •VDSL2: 100 Mpbs bi-directional rate for very short range

Cellular Radio (GSM/TDMA and CDMA)

•Connects to nearest transmitter; base station range of up to 5 miles. •Transmitter connects phone to mobile/landline networks. •850 / 1900 MHz bands (Americas); 900 / 1800 MHz bands (rest of world).

Dial up disadvantages, speed, etc

•Disadvantages: low data transfer, time to establish connection, errors •Fastest modems ~33.6 Kpbs; speed limit of phone line •Theoretical maximum downlink ~56 Kpbs •Compression may improve data transfer •Has been superseded; still in use as a backup or for areas without other support Using the V.90 or V.92 digital signaling protocol, a downlink speed of up to 56 Kbps is possible in theory, though rarely achieved in practice.

DHCP reservation

•For hosts that need same address each time. •Configure DHCP server with reserved host address per MAC address. •Centralized, easier to implement than static addressing.

LoS WISP

•Ground-based microwave antennas aligned with each other; transmit if no physical obstruction (usually atop tall buildings). •Spans great distances; no cabling infrastructure; lower latency than satellite. •Hard to maintain line of sight; expensive. •WISP may use Wi-Fi or proprietary equipment. •Range of frequencies; may be affected by 5G cellular phone service deployment.

Fiber Optic Internet Access

•Higher bandwidth, longer distance than copper cable •Has replaced copper as core of telecommunications networks •Being extended to individual homes and businesses •Two principal types of fiber optic network services: •Cable TV providers •Telecom providers

Authoritative name server

•Holds domain records and can respond authoritatively about hosts in the domains it manages. On a private network, such as an Active Directory (AD) domain, a name server must be running to host the AD DNS records. These records would not be made publicly available outside the LAN. On the Internet, public information about a domain, such as the location of its web and email servers, will be published to a name server. These are usually hosted by ISPs.

Client DNS

•IP address of DNS server to provide host/domain name resolution and locate Internet resources. •DNS also used on most local networks. •Often the gateway address; often a second server address provided for redundancy.

Default gateway

•IP address of a router to send packets outside of local network. •If no gateway, host can only communicate on local network.

IPv6

•IPv4 address pool is large, but limited. •IPv6 uses 128-bit addresses, massively increasing address pool. •Other improvements: simplified address headers, hierarchical addressing, support for time-sensitive traffic, new unicast address structure. •Large string of characters in binary or even decimal; affects clarity and accuracy. •Uses hexadecimal notation (0-9, A-F):

IPv6 and how it assigns address blocks

•IPv6 link-local addresses used for housekeeping •Span single subnet •Nodes on same link called "neighbors" •Start with fe80:: •Equivalent of APIPA •IPv6 host always has a link-local address

So how do we read binary?

•In binary, a digit can only be 0 or 1 •Values of the digits are powers of 2 •Converting 11101101 from binary to decimal: 128 64 32 16 8 4 2 1 1 1 1 0 1 1 0 1 128*1 64*1 32*1 16*0 8*1 4*1 2*0 1*1 = 237!

•2.4 GHz:

•Longer wavelength, longer range, propagates better through solids •Does not support many individual channels; is often congested; bluetooth can interfere •Increased risk of interference •Achievable data rates less than 5 GHz

•Routers and modems both connect to the Internet:

•Modem makes a physical link (like a switch). •Router makes logical forwarding decisions. •Often bundled in one device. A modem works at the same level as a switch, making a physical network link with the ISP's network.

Lightweight Directory Access Protocol (LDAP)

•Network resources are recorded as objects in a directory database. •X.500 standards allow directories to interact; full standard required a complex protocol. •LDAP allows X.500-compliant queries and updates over TCP/IP. •Widely supported; TCP/UDP 389.

The TCP/IP Protocol Suite FACTS:

•Networks have converged on use of TCP/IP protocol suite •Originally developed by US DoD; now an open standard Developments are implemented through the Internet Engineering Task Force (IETF) Standards are published as Request For Comments (RFCs). •Packet-based protocols (smaller packets mean the data will prob not get lost or damaged and easier to send) Routers choose the paths that packets take around the network from source to destination TCP/IP Protocols The main protocols in the suite provide addressing and transport services. The function of these protocols can be better understood by dividing them into layers. The TCP/IP suite uses a model with four distinct layers.

Layer: Application Layer

•Numerous protocols for network configuration, management, services; use TCP/UDP ports Address Resolution Protocol (ARP): Finds MAC address associated with IP address Internet Control Message Protocol (ICMP) which works at the network layer. ICMP delivers status and error messages and is used by diagnostic utilities such as ping and tracert.

Layer: Link/Network Interface Layer

•Puts frames on physical network •Not TCP/IP protocols as such; networking products and media (Ethernet, Wi-Fi) •Communications on local network •Data packaged in frames •Nodes identified by MAC address

Patch cord connects-

•RJ-45 port on panel to port on switch •Stranded cable; flexible, less efficient •5 m maximum length

Ethernet Over Power

•SOHO networks are unstructured, use a single router, incorporate smart appliances. •Wireless is obvious solution; WLAN bandwidth may be adequate. •There may be interference issues or appliances may not support Wi-Fi. •Ethernet over Powerline uses building power circuits; overlays carrier signal to transfer Ethernet frames. •Adapter plugs into electrical outlet; provides RJ-45 ports. •No configuration needed, but security can be configured. •Standards defined by IEEE 1901, managed by HomePlug Powerline Alliance.

Symmetric DSL

•Same uplink and downlink speeds •Useful for businesses, branch offices

Intrusion Detection System (IDS)

•Software and/or hardware that monitors for and quickly detects malicious behavior. •Can also analyze and alert administrators to infrastructure problems. •Can comprise sensors, detection software, and management software; each implementation is unique.

Dial up: Explain how it works and characteristics

•Telephone connection between computers. •Uses entire frequency range; not efficient, low bandwidth. •Phone charges apply; line cannot be used for voice at same time. •Modems at each end convert digital TO analog (MOdulation/DEModulation).

Proxy Server

•Used on enterprise networks as alternative to NAT. •Checks and forwards HTTP, email, or other requests from internal hosts to Internet; returns reply to the client. •May be transparent (no client configuration) or non-transparent (client must be configured with proxy's IP address and port, typically 8080).

Authentication Server

•Used on enterprise networks to ensure only authorized users can access accounts. •On Windows domain, Active Directory provides authentication based on Kerberos. Authentication, Authorization, and Accounting (AAA) server: consolidates authentication services across multiple access devices, such as switches, routers, and access points. Remote Authentication Dial-in User Service (RADIUS) is an example of an AAA protocol.

Cellular Radio Networks

•Wi-Fi bands have restricted range; fixed wireless requires large antenna. •Cellular radio wireless networking allows long-distance communications over smartphone devices. •Also used by IoT devices. (internet of things) such as a smart energy meter or Ring Doorbell

step 4

1.Message placed in store on recipient's server; client software connects with mailbox using POP3 (port 110) or IMAP (port 143). •POP3 more widely used; IMAP has more features.

Neither hub nor bridge appliances are widely used on networks anymore. Their functions have been replaced by-

Ethernet switches. Like hubs, switches can connect nodes together in a single network, repeating and regenerating signals over multiple ports. Like bridges, switches are used to reduce the effect of contention on network performance.

Ethernet allows nodes to send one another frames of data using-

MAC addresses. These frames would typically be transporting IP packets.

step 2

When the Exchange SMTP server starts to process the queue, it first contacts a DNS server to resolve the recipient's address (for example, [email protected]) to an IP address for the othercompany.com email server, listed as a Mail Exchanger (MX) record in DNS.

Network Address Port Translation (NAPT), which is also referred to as Port Address Translation (PAT) or as NAT overloading, is what?

a means for multiple private IP addresses to be mapped onto a single public address

A number of connectors have been designed for use with fiber optic cabling. Some types are more popular for multi-mode and some for single-mode. Connectors for MMF are usually-

color-coded beige, while those for SMF are blue. The core of each connector is a ceramic or plastic ferrule that ensures continuous reception of the light signals.

Simple Network Management Protocol (SNMP)

framework for management and monitoring network devices. SNMP consists of a management system and agents. The agent is a process running on a switch, router, server, or other SNMP-compatible network device. This agent maintains a database called a Management Information Base (MIB)

An Ethernet switch performs the same sort of function as a bridge but can provide many more-

ports.

Most cabled LANs are based on the Ethernet networking product, developed by-

the DIX consortium (Digital Equipment Corporation [DEC], Intel, and Xerox).

SSL/TLS is typically used with-

the HTTP application (referred to as HTTPS or HTTP Over SSL or HTTP Secure)

The subnet mask is used in conjunction with-

the IP address to determine whether another interface is located on a local or remote network. An interface must be configured with a subnet mask.

Ethernet standards are now maintained by-

the Institute of Electrical and Electronics Engineers (IEEE). Ethernet is technically known by the series of standards produced by the IEEE 802.3 working group.

internet Protocol and IP Addressing The core protocol in TCP/IP is-

the Internet Protocol (IP), which provides network and host addressing and packet forwarding between networks.

To configure an email account, you need-

the username, password, and default email address, plus incoming and outgoing server addresses and protocol types from the ISP.

The bridge keeps track of the MAC addresses attached to each segment. The bridge only passes signals from one segment to another if-

there is a match to the destination MAC address, reducing traffic loads in any one segment. The network should be designed so that relatively little traffic actually needs to pass over the bridge.

A subnet mask (or netmask) is used to distinguish-

these two components within a single IP address, The network number (network ID) and The host number (host ID). It is used to "mask" the host ID portion of the IP address and thereby reveal the network ID portion.

The signaling mechanism uses various encoding methods to represent the 1s and 0s of computer data as electrical or light pulses. The transceiver in the NIC is responsible for-

transmitting and receiving these pulses in the agreed frame format.

An optical fiber consists of an-

ultra-fine core of glass to carry the light signals surrounded by glass or plastic cladding, which guides the light pulses along the core, and a protective coating called the buffer. The fiber optic cable is contained in a protective jacket and terminated by a connector.