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64 Cards in this Set
- Front
- Back
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LS Algorithms
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Link State Algorithms - algorithms that must be aware of the cost of each link in the network
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decentralized routing algorithm
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least-cost path is carried out in an iterative, distribute manner. No node has complete information about the costs of all network links
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static routing algorithms
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routes change very slowly over time, often as a result of human intervention
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dynamic routing algorithms
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change the routing paths as the netwok traffic loads or topology change
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load sensitive alogirthm
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link costs vary danimlly to reflect the current level of congestion in the underlying link
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load-insensitve
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link's cost does not explicitly reflect its current or past level of congestion
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link-state broadcast algorithm
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all nodes have an identical and complete view of the network
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distance vector
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iterative, asynchronous and distributed algorithm using global information
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routing tables
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Each node's table of information that depicts that node's view of the distance from a certain node to other nodes
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routing loop
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a packet bounces back and forth between two nodes based on the information they both have
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(AS)
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Autonomous system - a group of routers that are typically under the same administrative control that all run the same routing algorithm
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Autonomous system routing protocol
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routing algorithm running within an autonomous system
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gateway routers
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routers that forward packets out of an AS
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RIP
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Routing Information protocol
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OSPF
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Open Shortest Path First
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routing table
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each node's interpretation about the paths between each node
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BGP
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Border Gateway protocol - AS routing across subnetworks
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ASN
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autonomous system number
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stub network
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all traffic entering that must be destined for that network and all trafic leaving must have originated in that network
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multi-homed stub network
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connected to the rest of the network via two different providers
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links
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communication channels that connect adjacent nodes along the communication path
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link layer protocol
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defines the format of the packets exchanged between the nodes at the ends of the link as well as the actions taken by these nodes when the packets are sent and received
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frames
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unites of data exchanged in the link layer protocol
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NIC
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network interface card (network adapter) where the link layer is implemented
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bit-level error detection and correction
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detecting and correcting the corruption of bits in a link-layer frame sent from one node to another physically coneccted neighboring node
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parity bit (even)
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even parity bit makes sure all bits plus parity bit is even
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FEC
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Forward error correction - ability of the receiver to both detect and correct errors
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CRC
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Cyclic Redundancy Check
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generator (CRC)
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r + 1 bit pattern
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point-to-point link
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single sender at one end of the link and a single receiver at the other end of the link
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broadcast link
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multiple sending and receiving nodes all connected to the same single shared broadcast channel
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Multiple Access problem
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how to coordinate the access of multiple sending and receiving nodes to a shared broadcast channel
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Multiple access protocols
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nodes regulate their transmission into the shared broadcast channel
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channel partitioning protocols
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split the channel into frequencies or times
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CDMA
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code division multiple access - different codes for each node and then encrypted based on code
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Random Access protocols
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transmitting node always transmits at the full rate of the channel, when there is a collission each node retransmits its frame
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successful slot
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exactly one node transmits
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CSMA
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carrier sense multiple access
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CSMACD
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CSMA with collission detection
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carrier sensing
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if someone else is speaking wait until they are finished
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collission detection
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if someone else begins talking at the same time stop talking - transmitting node listens to the channel while transmitting. If it detects that another node is transmitting an interfereing frame it stops
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chanell propagation delay
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the time it takes for a signal to propagate from one of the nodes to another
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Polling Protocol
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One master that polls other users (tells them when they can talk)
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Token passing protocol
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token passed around, only talk when have token
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Token Ring
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class of lan technologies consists of token passing technologies
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FDDI
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fiber distributed data interface
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What is a link layer address called
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LAN address, physical address, MAC address
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MAC
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media access control
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mac broadcast address
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FF-FF-FF-FF-FF-FF
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How many bits is a mac address
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48
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ARP
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address resolution protocol translates between IP and MAC addresses
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ARP table
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contains mappings of ip adddresses to mac addresses
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ARP packet fields
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sending and receiving ip and mac addresses
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hub
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boosts signals and sends it to everyone else connected
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Siwtch
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only sends information to the node it is supposed to go to
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efficiency of ethernet
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long-run fraction of time during which frames are being transmitted on the channel without collisions when there is a large number of active nodes
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repeater
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a physical layer device that receives a signal on the input side and regenerates the signal on the output side
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transparent
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switches are transparent, nodes don't know they are sending information to the switch
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filtering
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switch function that determines wheter a frame should be forwarded to some interface or should be dropped
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forwarding
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switch function that determines the interfaces to which a fframe should be directed and then moves the frame to those interfaces
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switch table
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contains entries for some but not necessarily all of the nodes on a lan
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self-learning
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switches learn the nodes connected to it
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aging-time
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how long the switch waites to delete an address from its table
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plug-and-play devices
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require no inervention from a network administer or user
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