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Networking and Internetworking Devices. Repeaters Bridges Routers Gateways Routing Algorithms. Homework. p.641 prob 1-18. Connecting Devices and the OSI Model. Repeater and OSI Model. A Repeater. Function of a Repeater. Bridge and the OSI Model. Bridges.
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Networking and Internetworking Devices • Repeaters • Bridges • Routers • Gateways • Routing Algorithms
Homework • p.641 prob 1-18
Connecting Devices and the OSI Model
Bridges • Reduces Collision Domain / Congestion • Simple • Addresses manually entered • Multiport • Transparent • Builds routing table itself • Updates table based on source addresses
Routing Concepts • Least cost routing • Hop count • Link-quality • Speed, congestion, link medium
Routing concepts Non-adaptive Adaptive Packet Lifetime
Gateway • Each Side Unaware of The OTHER • Protocol Converter • SNA -> TCP/IP • AppleTalk -> TCP/IP • Novell Netware -> TCP/IP
Other Devices • Multi-Protocol Routers • IPX, TCP/IP • Brouter • Router if known protocol • Bridge otherwise
Switches • Function at Level 2 • Bridging Capability • Store and Forward • Telex • Cut-Through • Immediate Transfer
Routing Switches • Function as routers • Faster than traditional routers • USE Level 3 – Network Addresses
Distance Vector Routing • Knowledge about the entire network • Routing only to neighbors • Information Sharing with neighbors
Link State Routing • Knowledge of neighborhood • Shares with all routers – flooding • Information sharing when change
Dijkstra Algorithm • Breadth Search from root • Select lowest cost • Add node and arc
Routing Classifications • Adaptive routing (dynamic) • Non-adaptive routing (fixed or static)
Dynamic Routing Algorithms • Distance Vector Routing • Link state routing
Routing Algorithms • Distance Vector Routing • Each link is assigned a weight • Distance to the destination is the sum of the weights along the path to the destination
Routing Algorithms • Distance Vector Routing • Each router sends its entire information about the entire network to its neighbors. • Neighbors are other routers with direct link to it. • Information are shared periodically, even if nothing has changed. • Eventually, every router will learn about other routers on the network. • Slow convergence (it takes longer for all routers to receive all information)
Distance Vector Routing Protocol • RIP (Routing Information Protocol) • Each router uses broadcasting to send its entire information to its neighbors every 30 seconds. • The best path is based on the least number of hops. • It’s suitable for small networks • RIP is used by IPX/SPX and TCP/IP.
Routing Algorithms • Link state routing • If there is a change, each router sends its information about its neighbors to every other router in the network using flooding. • A router, periodically sends a message to its neighbors, the response indicates that the device is alive and functioning. • No response, change has occurred.
Link State Routing Protocol • OSPF (Open Shortest Path First) • More efficient than RIP • Only the changes are sent • each router sends its information about its neighbors to every other router in the network using flooding. • A router, periodically sends a message to its neighbors, the response indicates that the device is alive and functioning. • No response, change has occurred.
Finding the Shortest Path • Select a node (A) and make it permanent • Examine each of the adjacent nodes to A. • Relabel each one with the distance to A. • Make the one with the smallest label permanent. (14) • This becomes the new working node.
