Computer Networking Semester 2 Unit 8

AP modes

An AP can be set to operate as a traditional access point, a repeater, or a wireless bridge

classless addressing

An IP addressing convention that alters the rules of classful IPv4 addressing to create subnets in a network.

VLAN hopping

An attack in which the attacker generates transmissions that appear, to the switch, to belong to a protected VLAN.

native VLAN

An untagged VLAN on a switch that will automatically receive all untagged frames.

VTP (VLAN Trunk Protocol)

Cisco's protocol for exchanging VLAN information over trunks.

installing a second NIC

How do you improve fault tolerance

24 bits

How many bits of a Class A IP address are used for host information?

CIDR block

In CIDR notation, the forward slash plus the number of bits used for the network ID. For example, the CIDR block for 199.34.89.0/22 is /22.

magic number

In the context of calculating subnets, the difference between 256 and the interesting octet (any octet in the subnet whose value is something other than 0 or 255). It can be used to calculate the network IDs in all the subnets of a larger network.

Auto-negotiate mode

Most switches run in whaat?

-some advanced devices have all the functions of a managed switch but add Layer 3 capabilities -these switches offer a performance advantage over traditional routers

Multilayer switches

-geographic locations -departmental boundaries -device types

Networks are commonly segmented according to one of which groupings?

-operate at the Network layer and work with packets -advanced devices that connect separate logical networks to form an internetwork -can be used to create complex internet works with multiple paths creating fault tolerance and load sharing

Routers

A set of rules that routers use to exchange information so that all routers have accurate information about an internetwork to populate their routing tables

Routing protocols

-10 Mbps half-duplex -100 Mbps half-duplex -10 Mbps. Full-duplex -100 Mbps full-duplex

Switch port modes of operations are?

802.1Q

The IEEE standard that specifies how VLAN and trunking information appears in frames and how switches and bridges interpret that information.

trunking

The aggregation of multiple logical connections in one physical connection between connectivity devices. In the case of VLANs, a trunk allows two switches to manage and exchange data between multiple VLANs.

site prefix

The first four blocks or 64 bits of an IPv6 address that normally identify the network. Also called global routing prefix.

global routing prefix

The first four blocks or 64 bits of an IPv6 address that normally identify the network. Also called site prefix.

trunk port

The interface on a switch capable of managing traffic from multiple VLANs.

access port

The interface on a switch used for an end node. Devices connected to access ports are unaware of VLAN information.

-double tagging -switch spoofing

What are the two approaches to VLAN hopping

Network documentation is easier to manage.

What do well-chosen subnets accomplish?

it can limit network performance

What if a NIC is slow?

identify the physical characteristics the card must match

What is important in selection a network adapter?

2h - 2 = Z

What is the formula for determining the number of possible hosts on a network?

Eight

What is the least number of bits you would need to borrow from the network portion of a Class B subnet mask to get at least 130 hosts per subnet?

-Don't use the default VLAN. -Change the native VLAN to an unused VLAN ID. -Disable auto-trunking on switches that don't need to support traffic from multiple VLANs. -On switches that do carry traffic from multiple VLANs, configure all ports as access ports unless they're used as trunk ports. -Specify which VLANs are supported on each trunk instead of accepting a range of all VLANs. -Use physical security methods such as door locks to restrict access to network equipment.

What mitigation efforts will reduce the risk of VLAN hopping

-incorrect port mode -incorrect VLAN assignment -VLAN isolation

What should you consider if you have configuration errors?

802.1Q

Which IEEE standard determines how VLANs work on a network?

256 - the interesting octet 2h

Which formulas can be used to calculate the magic number?

The fourth one

Which hexadecimal block in an IPv6 address is used for the Subnet ID?

To increase the number of networking devices on a network

Which of the following is not a good reason to segment a network?

Trunk

Which port mode on a switch enables that port to manage traffic for multiple VLANs?

DHCP relay agent

While designing your network's VLAN topology, your team has decided to use a centrally managed DHCP server rather than creating a separate DHCP server for each VLAN. What software will you need to make the central DHCP server accessible across VLANs?

shared system memory

a NIC's onboard processor selects a region of RAM on the computer and writes to it as though it were buffer space on the adapter

Preboot Execution Environment (PXE)

compliant adapters allow a computer to download and OS instead of booting it from a local hard drive-this feature is used on diskless workstations that do not store the OS locally

VLAN support

enable this setting to assign wireless networks to wired VLANs

Automatic link aggregation

enables you to install multiple NICs in one computer and aggregate the bandwidth

Traffic priority

if your AP is configured for multiple networks you can assign a priority to packets coming from each network

adjustable transmit power

lets you control the power and range of the wireless network signal

network interface cards

makes the connection between a computer and the network medium-performance and reliability of this are crucial to the computer's network performance

RAM buffering

means NIC includes additional memory to provide temporary storage for incoming and outgoing network data that arrives at the NIIC faster than it can be sent out

Bus mastering

permits a network adapter to take control of the computer's bus to initiate and manage data transfers to and from the computer's memory

Wi-Fi Multimedia

provides quality of service (QoS) settings for multimedia traffic, giving priority to streaming audio or video

shared adapter memory

the adapter's buffers map directly to RAM on the cojmputer

Advanced Configuration and Power Management Interface

this offers Wake-on-LAN

multiple SSIDs

two or more wireless networks can be created with different security settlings

Fragment-free switching

-Is a method in which the switch reads enough of the fame to guarantee that its at least the minimum size for the network type -medium speed switching performance -all errors except undersized frames forwarded

Cut-through switching

-Is the fastest method in which the switch reads only enough of the incoming frame to determine the frame's source and destination addresses -fastest switching performance -all errors forwarded

Store-and-forward switching

-Requires that the switch read the entire frame into its buffers before forwarding it -slowest switching performance -no error frames forwarded

Switches

-Work at the Data Link (Layer 2) of the OSI model -send broadcast frames out of all ports -each port is considered a collision domain -ports can operate in full-duplex mode -allows connected devices to transmit and receive simultaneously eliminating the possibility of a collision

onboard co-processors

-enable the card to process incoming and outgoing network data without requiring service from the CPU -security features on some-high-end NICs allow them to handle several protocol functions, such as IPsec and other encryption services related to authentication and payload protection -Quality of service (QoS) allows prioritizing time-sensitive data

tag

A VLAN identifier added to a frame's header according to specifications in the 802.1Q standard.

native VLAN mismatch

A configuration error where switch ports on each end of a trunk are configured with different native VLAN assignments. Also called a VLAN mismatch.

VLAN mismatch

A configuration error where switch ports on each end of a trunk are configured with different native VLAN assignments. Also called a native VLAN mismatch.

ANDing

A logical process of combining bits.

-enhance security -improve performance -simplify troubleshooting

A network administrator might separate a networks traffic into smaller portions to accomplish what?

VLAN (virtual local area network or virtual LAN)

A network within a network that is logically defined by grouping ports on a switch so that some of the local traffic on the switch is forced to go through a router, thereby limiting the traffic to a smaller broadcast domain.

default VLAN

A preconfigured VLAN on a switch that includes all the switch's ports and cannot be renamed or deleted.

ip helper-address

A robust Cisco command that can be configured to create and send helper messages that support several types of UDP traffic, including DHCP, TFTP, DNS, and TACACS+.

CIDR notation

A shorthand method for denoting the distinction between network and host bits in an IP address.

CIDR (Classless Interdomain Routing)

A shorthand method for identifying network and host bits in an IP address.

DHCP relay agent

A small application that works with a centrally managed DHCP server to provide DHCP assignments to multiple subnets and VLANs.

VLSM (Variable Length Subnet Mask)

A subnetting method that allows subnets to be further subdivided into smaller and smaller groupings until each subnet is about the same size as the needed IP address space.

Managed switches

A switch that can be configured via a command-line interface or a web-based management GUI, and sometimes can be configured in groups.

managed switch

A switch that can be configured via a command-line interface or a web-based management GUI, and sometimes can be configured in groups.

unmanaged switch

A switch that provides plug-and-play simplicity with minimal configuration options and has no IP address assigned to it.