ITN Exam 2 - U AKRON

physical address (MAC address)

Used for NIC to NIC communications on the same Ethernet network.

logical address (IP address)

Used to send the packet from the source device to the destination device. The destination IP address may be on the same IP network as the source or it may be on a remote network.

UDP

User Datagram Protocol. Used instead of TCP when guaranteed delivery of each packet is not necessary. UDP uses a best-effort delivery mechanism. Used for streaming, video calls

Neighbor Solicitation (NS)

When a device is assigned a global IPv6 unicast or link-local unicast address, it may perform duplicate address detection (DAD) to ensure that the IPv6 address is unique. To check the uniqueness of an address, the device will send an NS message with its own IPv6 address as the targeted IPv6 address, as shown in the figure. If another device on the network has this address, it will respond with an NA (Neighbor S)

metric

a specification consists of maximum transition unit (MTU), bandwidth and latency the router uses the metric value to choose the path to the destination when there are multiple routes available

public addresses

addresses which are globally routed between internet service provider (ISP) routers.

anycast

An IPv6 anycast address is any IPv6 unicast address that can be assigned to multiple devices. A packet sent to an anycast address is routed to the nearest device having that address. Anycast addresses are beyond the scope of this course. An ___________ address is any unicast IPv6 address that is assigned to multiple devices.

Flow Label

in IPv6 header is a 20-bit field that provides a special service for real-time applications. This field can be used to inform routers and switches to maintain the same path for the packet flow so that packets will not be reordered.

Traffic Class

indicates the packet's priority - it is similar to the DiffServ field in IPv4 packets

ipv4 multicast address

ipv4 multicast address Multicast IPv4 addresses use the reserved class D address range of 224.0.0.0 to 239.255.255.255.

directed broadcast

is a message sent to all hosts on a specific network. It is useful for sending a broadcast to all hosts on a nonlocal network.

traceroute (tracert)

is a utility that is used to test the path between two hosts and provide a list of hops that were successfully reached along that path uses the ICMP (Internet Control Message Protocol) to send and receive echo-request and echo-reply messages.

Differentiated Services (DS)

is an 8-bit field used to determine the priority of each packet. The six most significant bits of the ________________ field are the differentiated services code point (DSCP) bits and the last two bits are the explicit congestion notification (ECN) bits. On IPv6 this is equivalent to Traffic Class

Stateful DHCPv6

is similar to DHCP for IPv4. A device can automatically receive its addressing information including a GUA, prefix length, and the addresses of DNS servers from a stateful DHCPv6 server the RA message suggests devices use the following: The router local link address, which is the RA source IPv6 address, for the default gateway address. A stateful DHCPv6 server to obtain a global unicast address, DNS server address, domain name and other necessary information.

Solicited node multicast

is similar to the all-nodes multicast address. The advantage of _________________ is that it is mapped to a special Ethernet multicast address. This allows the Ethernet NIC to filter the frame by examining the destination MAC address without sending it to the IPv6 process to see if the device is the intended target of the IPv6 packet.

Default Gateway

is the address of the network device (i.e., router or Layer 3 switch) that can route traffic to other networks. If you use the analogy that a network is like a room, then the default gateway is like a doorway. If you want to get to another room or network you need to find the doorway.

Address Resolution Protocol (ARP)

is used to discover the MAC address of any host on the local network. When a PC wants to send data on the network, it always knows the IP address of the destination. However, it also needs to discover the MAC address of the destination. ARP is the protocol that is used to discover the MAC address of a host that belongs to the same network.

Router advertisement

messages are sent by IPv6-enabled routers every 200 seconds to provide addressing information to IPv6-enabled hosts. The RA message can include addressing information for the host such as the prefix, prefix length, DNS address, and domain name. A host using Stateless Address Autoconfiguration (SLAAC) will set its default gateway to the link-local address of the router that sent the RA.

NVRAM

nonvolatile memory that stores the startup configuration of a device On router this stores the startup config to retain contents when power is removed to store the startup configuration file

private addresses

not all available IPv4 addresses can be used on the internet. There are blocks of addresses called private addresses that are used by most organizations to assign IPv4 addresses to internal hosts. private IPv4 addresses 10.0.0.0 - 10.255.255.255 172.16.0.0 - 172.31.255.255 192.168.0.0 - 192.168.255.255

Maximum Transmission Unit (MTU)

one major characteristic of the media that the network layer considers: the maximum size of the PDU that each medium can transport. This characteristic is referred to as _________ _________ ________ an intermediate device, usually a router, must split up an IPv4 packet when forwarding it from one medium to another medium with a smaller _____ ____ ____. This process is called fragmenting the packet, or fragmentation. Fragmentation causes latency

Full-duplex

Both devices can simultaneously transmit and receive on the shared media. The data link layer assumes that the media is available for transmission for both nodes at any time. Ethernet switches operate in this mode by default, but they can operate in half-duplex if connecting to a device such as an Ethernet hub. does not require media arbitration

Half-duplex

Both devices can transmit and receive on the media but cannot do so simultaneously. WLANs and legacy bus topologies with Ethernet hubs use the this mode. allows only one device to send or receive at a time on the shared medium.

classful addressing (Class A, B, C, D, and E)

Class A (0.0.0.0/8 to 127.0.0.0/8) - Designed to support extremely large networks with more than 16 million host addresses. Class A used a fixed /8 prefix with the first octet to indicate the network address and the remaining three octets for host addresses (more than 16 million host addresses per network). Class B (128.0.0.0 /16 - 191.255.0.0 /16) - Designed to support the needs of moderate to large size networks with up to approximately 65,000 host addresses. Class B used a fixed /16 prefix with the two high-order octets to indicate the network address and the remaining two octets for host addresses (more than 65,000 host addresses per network). Class C (192.0.0.0 /24 - 223.255.255.0 /24) - Designed to support small networks with a maximum of 254 hosts. Class C used a fixed /24 prefix with the first three octets to indicate the network and the remaining octet for the host addresses (only 254 host addresses per network).

prefix length

(also known as Network Portion in iPv4) is represented in slash notation and is used to indicate the network portion of an IPv6 address.

Identification field

A 16-bit number that's used to group messages together. Reorders fragmented packets

Packet

A chunk of data sent over a network. Larger messages are divided into packets that may arrive at the destination in order, out-of-order, or not at all.

Router

A device that transfers data from one network to another in an intelligent way accepts a packet and accesses its routing table to determine the appropriate exit interface based on the destination address. The router then forwards the packet out of that interface. two primary functions packet forwarding path selection

Internet Protocol Version 4 (IPv4)

A group of TCP/IP standards that uses IP addresses that have 32 bits. is a 32-bit hierarchical address that is made up of a network portion and a host portion

access method

A method to control which computer is allowed to use transmission media at a certain time.

Ethernet frame

An Ethernet frame is not processed and is discarded if it is smaller than the minimum (64 bytes) or if the calculated frame check sequence (FCS) value does not match the received FCS value.

Trailer

Error Detection determines if the frame arrived without error. It places a logical or mathematical summary of the bits that comprise the frame in the trailer. The data link layer adds error detection because the signals on the media could be subject to interference, distortion, or loss that would substantially change the bit values that those signals represent. Frame Stop indicates the end of the frame

header

Frame Start Indicates the beginning of a frame Addressing Source and destination MAC addresses Type Identifies the layer 3 protocol in the data field (Layer 3 PDUs are encapsulated within the data field of the frame) Control Identifies flow control services such as quality of service. Gives forwarding priority to certain types of messages **However, the structure of the frame and the fields that are contained in the header vary according to the protocol. Different data link layer protocols may use different fields, like priority/quality of service, logical connection control, physical link control, flow control, and congestion control**

Media independent

IP does not concern itself with the type of frame required at the data link layer or the media type at the physical layer. IP can be sent over any media type: copper, fiber, or wireless.

IP Header

IP encapsulates the transport layer (the layer just above the network layer) segment or other data by adding an IP header used to deliver the packet to the destination host.

Connectionless

IP is _________________, meaning that no dedicated end-to-end connection is created by IP before data is sent. Connectionless communication is conceptually similar to sending a letter to someone without notifying the recipient in advance.

route timestamp

Identifies how much time has passed since the route was learned. "route timestamp"

route source

Identifies how the route was learned Common __________ _______s (codes) include these: L - Directly connected local interface IP address C - Directly connected network S - Static route was manually configured by an administrator O - OSPF D - EIGRP

outgoing interface

Identifies the exit interface to use to forward a packet toward the final destination. "outgoing interface"

Physical Topology

Identifies the physical connections and how end devices and intermediary devices (i.e, routers, switches, and wireless access points) are interconnected. The topology may also include specific device location such as room number and location on the equipment rack. Usually point to point or star topologies

Neighbor Advertisement (NA)

If another device on the network has this address, it will respond with an NA message. This NA message will notify the sending device that the address is in use. If a corresponding NA message is not returned within a certain amount of time, the unicast address is unique and acceptable for use. (Neighbor A)

Router solicitation

In IPv6, a query from a host to find routers and get information to configure itself. An IPv6-enabled router will also send out an RA message in response to an RS message. In the figure, PC1 sends a RS message to determine how to receive its IPv6 address information dynamically.

Interface ID

In TCP/IP version 6, the last 64 bits or 4 blocks of an IP address that identify the interface. t is strongly recommended to use a 64-bit Interface ID for most networks. This is because stateless address autoconfiguration (SLAAC) uses 64 bits for the Interface ID. It also makes subnetting easier to create and manage.

CSMA/CA

In wireless environments it may not be possible for a device to detect a collision. CMSA/____ does not detect collisions but attempts to avoid them by waiting before transmitting. Each device that transmits includes the time duration that it needs for the transmission. All other wireless devices receive this information and know how long the medium will be unavailable.

Ipv6 Multicast

Ipv6 Multicast all-node multicast FF02::1 are for all IPv6 enabled devices on the link or network. all router multicast FF02::2 is for all IPv6 routers that exist on the network.

netstat -r

On a Windows host, the route print or __________ ____ command can be used to display the host routing table. Both commands generate the same output. The output may seem overwhelming at first, but is fairly simple to understand Command displays three sections related to current TCP/IP Connections Interface List - Lists the Media Access Control (MAC) address and assigned interface number of every network-capable interface on the host, including Ethernet, Wi-Fi, and Bluetooth adapters. IPv4 Route Table - Lists all known IPv4 routes, including direct connections, local network, and local default routes. IPv6 Route Table - Lists all known IPv6 routes, including direct connections, local network, and local default routes

remote routes

One of three types of routes in a routers routing table These are the routes the router does not have a direct connection and may be learned: • Manually - with a static route • Dynamically - by using a routing protocol to have the routers share their information with each other this routing table entry has the next hop address associated with a destination network

directly-connected routes

One of three types of routes in a routers routing table These routes are automatically added by the router, provided the interface is active and has addressing.

default route

One of three types of routes in a routers routing table this forwards all traffic to a specific direction when there is not a match in the routing table

Media Access Control (MAC)

One of two sublayers that together make up the data link layer in the OSI. It is responsible for data encapsulation and media access control. It provides data link layer addressing and it is integrated with various physical layer technologies. controls the NIC and other hardware that is responsible for sending and receiving data on the wired or wireless LAN/MAN medium provides media access control, allowing multiple devices to communicate over a shared (half-duplex) medium. Full-duplex communications do not require access control. The ________________ sublayer is responsible for the placement and retrieval of frames on and off the media. The ____________ sublayer is also responsible for adding a header and a trailer to the network layer protocol data unit (PDU). defines the way data frames get placed on the media. Utiltizes CSMA/CD, Protocols define the rules for access to different media. 1. Controls the NIC responsible for sending and receiving data on the physical medium. 2. Implements a trailer to detect transmission errors. 3. Provides synchronization between source and target nodes. 4. Integrates various physical technologies. 5. Provides a mechanism to allow multiple devices to communicate over a shared medium.

Logical Link Control (LLC)

One of two sublayers that together make up the data link layer in the OSI. defines the software processes that provide services to the network layer protocols. The information is placed by LLC in the frame and identifies which network layer protocol is being used for the frame communicates between the networking software at the upper layers and the device hardware at the lower layers. It places information in the frame that identifies which network layer protocol is being used for the frame. takes the network protocol data, which is typically an IPv4 or IPv6 packet, and adds Layer 2 control information to help deliver the packet to the destination node. is implemented in software and enables the data link layer to communicate with the upper layers of the protocol suite. 1. Enables IPv4 and IPv6 to utilize the same network interface and media. 2. Places information in the frame that identifies which network layer protocol is being used for the frame. 3. Adds Layer 2 control information to network protocol data.

MAC sublayer - data encapsulation

The MAC sublayer provides data encapsulation: Frame delimiting - The framing process provides important delimiters to identify fields within a frame. These delimiting bits provide synchronization between the transmitting and receiving nodes. Addressing - Provides source and destination addressing for transporting the Layer 2 frame between devices on the same shared medium. Error detection - Includes a trailer used to detect transmission errors

SLAAC

Stateless Address Auto Configuration allows a device to configure a Global Unicast Address (GUA) without the services of DHCPv6. • Devices obtain the necessary information to configure a GUA from the ICMPv6 Router Advertisement (RA) messages of the local router. • The prefix is provided by the RA and the device uses either the EUI-64 or random generation method to create an interface ID. uses ICMPv6 messages when dynamically assigning an IPv6 address to a host

Routing

The network layer provides services to direct the packets to a destination host on another network. To travel to other networks, the packet must be processed by a router. The role of the router is to select the best path and direct packets toward the destination host in a process known as routing. A packet may cross many routers before reaching the destination host. Each router a packet crosses to reach the destination host is called a hop.

Header Checksum (IPv4)

The 16-bit field is used for error checking of the IP header. The checksum of the header is recalculated and compared to the value in the checksum field. If the values do not match, the packet is discarded.

Frame Check Sequence

The FCS field in a frame is used to detect any errors in the transmission and receipt of a frame. This is done by comparing the CRC value within the frame against a computed CRC value of the frame. If the two values do not match, then the frame is discarded. CRC checks the integrity of the frame. CRC Definiti This part of the trailer is used to determine if the frame has been modified during transit.​ If the integrity of the frame is verified, the frame is forwarded. If the integrity of the frame cannot be verified, then the frame is dropped. A mathematical algorithm that is executed on a data string by both the sender and the receiver of the data string. If the calculated CRC values match, the receiver can conclude that the data string was not corrupted during transmission.

Best effort delivery (IP)

The IP protocol does not guarantee that all packets that are delivered are, in fact, received. This is up to other protocols to manage the process of tracking packets and ensuring their delivery ________ _______ __________

Local host

This is a destination host that is on the same local network as the sending host. The source and destination hosts share the same network address

IP Encapsulation

The network layer encapsulates the protocol data unit (PDU) from the transport layer (the layer just above the network layer) into a packet. The encapsulation process adds IP header information, such as the IP address of the source (sending) and destination (receiving) hosts. The encapsulation process is performed by the source of the IP packet.

Internet Protocol Version 6 (IPv6)

The next generation of the IP protocol that addresses weaknesses of IPv4 and provides several significant improvements. Increased address space - IPv6 addresses are based on 128-bit hierarchical addressing as opposed to IPv4 with 32 bits. Improved packet handling - The IPv6 header has been simplified with fewer fields. Eliminates the need for NAT

EUI-64

This process uses the 48-bit Ethernet MAC address of a client, and inserts another 16 bits in the middle of the 48-bit MAC address to create a 64-bit interface ID

Logical Topology

Topology that refers to the way a network transfers frames from one node to the next. This topology identifies virtual connections using device interfaces and Layer 3 IP addressing schemes. data link layer "sees" this topology of a network when controlling data access to the media. It is the this topology that influences the type of network framing and media access control used.

TCP

Transmission Control Protocol - provides reliable, ordered, and error-checked delivery of a stream of packets on the internet. TCP is tightly linked with IP and usually seen as TCP/IP in writing.

CSMA/CD

These networks operate in half-duplex mode, meaning only one device can send or receive at a time. This requires a process to govern when a device can send and what happens when multiple devices send at the same time. The access method rule of communication dictates how a network device is able to place a signal on the carrier. CSMA/CD dictates those rules on an Ethernet network Used to determine when the communications channels are clear and when the device is free to transmit data. It works by detecting a collision in the medium and backing off (after transmitting a jam signal) as necessary. When one host wants to transmit a frame, it listens on the medium to check if the medium is busy. After it senses that no one else is transmitting, the host starts transmitting the frame, it also monitors the current level to detect a collision. If it detects a collision, it transmits a special jam signal so that all other hosts can know there was a collision. The other host will receive this jam signal and stop transmitting. After this, both hosts enter an exponential backoff phase and retry transmission.

Next Header

This 8-bit field is equivalent to the IPv4 Protocol field. It indicates the data payload type that the packet is carrying, enabling the network layer to pass the data to the appropriate upper-layer protocol.

Hop Limit

This 8-bit field replaces the IPv4 TTL field. This value is decremented by one by each router that forwards the packet. When the counter reaches 0 the packet is discarded and an ICMPv6 message is forwarded to the sending host, indicating that the packet did not reach its destination. ICMPv6 uses the hop limit field in the IPv6 packet header to determine if the packet has expired. If the hop limit field has reached zero, a router will send a time exceeded message back towards the source indicating that the router cannot forward the packet

Protocol

This field is used to identify the next level protocol. The 8-bit binary value indicates the data payload type that the packet is carrying, which enables the network layer to pass the data to the appropriate upper-layer protocol. IPv4 header field identifies the upper layer protocol carried in the packet

Remote host

This is a destination host on a remote network. The source and destination hosts do not share the same network address

De-encapsulation

When the packet arrives at the network layer of the destination host, the host checks the IP header of the packet. If the destination IP address within the header matches its own IP address, the IP header is removed from the packet. After the packet is de-encapsulated by the network layer, the resulting Layer 4 PDU is passed up to the appropriate service at the transport layer. The de-encapsulation process is performed by the destination host of the IP packet.

version

Which term describes a field in the IPv4 packet header that contains a 4-bit binary value set to 0100?

Payload Length

a 16-bit field that indicates the length of the data portion or payload of the IPv6 packet (IPv6)

loopback addresses

are more commonly identified as only 127.0.0.1, these are special addresses used by a host to direct traffic to itself. For example, it can be used on a host to test if the TCP/IP configuration is operational verfies the TCP/IP stack on the device is working correctly the loopback address for ipv6 is 0:0:0:0:0:0:0:1 or ::1

Extension Headers

are optional and are placed between the IPv6 header and the payload. EHs are used for fragmentation, security, to support mobility and more.

ping

command is an IPv4 and IPv6 testing utility that uses ICMP echo request and echo reply messages to test connectivity between hosts and provides a summary that includes the success rate and average round-trip time to the destination

Time-to-Live (TTL)

contains an 8-bit binary value that is used to limit the lifetime of a packet. The source device of the IPv4 packet sets the initial _______ value. It is decreased by one each time the packet is processed by a router. If the _______ field decrements to zero, the router discards the packet and sends an Internet Control Message Protocol (ICMP) Time Exceeded message to the source IP address. Because the router decrements the _______ of each packet, the router must also recalculate the Header Checksum.

link-local address

enables a device to communicate with other IPv6-enabled devices on the same link and only on that link (subnet). Packets with a source or destination LLA cannot be routed beyond the link from which the packet originated. The GUA is not a requirement. However, every IPv6-enabled network interface must have an LLA IPv6 LLAs are in the fe80::/10 range

ICMPv6

has new features and improved functionality not found in ICMPv4, including four new protocols as part of the Neighbor Discovery Protocol (ND or NDP) Messaging between an IPv6 router and an IPv6 device, including dynamic address allocation are as follows: Router Solicitation (RS) message Router Advertisement (RA) message Messaging between IPv6 devices, including duplicate address detection and address resolution are as follows: Neighbor Solicitation (NS) message Neighbor Advertisement (NA) message

Routing table

hosts ensure that their packets are directed to the correct network destination by using their own local routing table that contains a route to the loopback interface, a local network route, and a remote default route.​ Hosts must maintain their own local routing table to ensure that network layer packets are directed to the correct destination network. This local table typically contains a route to the loopback interface, a route to the network that the host is connected to, and a local default route, which represents the route that packets must take to reach all remote network addresses.

Internet Control Message Protocol (ICMP)

provides feedback about issues related to the processing of IP packets under certain conditions. The ICMP messages common to both ICMPv4 and ICMPv6 include: • Host reachability • Destination or Service Unreachable • Time exceeded

show ip route

show ip route privileged EXEC mode command is used to view the IPv4 routing table on a Cisco IOS router

next-hop

the destination router indicated by the outgoing interface entry in the routing table "next-hop"

Automatic Private IP Addressing (APIPA) addresses

used by a Windows DHCP client to self-configure in the event that there are no DHCP servers available. Link-local addresses can be used in a peer-to-peer connection but are not commonly used for this purpose. (169.254.0.0 /16 or 169.254.0.1 to 169.254.255.254)

hextet

x:x:x:x:x:x:x:x the unofficial term used to refer to a segment of 16 bits, or four hexadecimal values. Each "x" is a single hextet which is 16 bits or four hexadecimal digits.