CS 350Chapter-9,10

Implementation of Connectionless Service

Routing within a datagram network

ISP’s equipment

A’s table (initially) A’s table (later) C’s Table E’s Table

Implementation of Connection-Oriented Service

Routing within a virtual-circuit network

ISP’s equipment

A’s table C’s Table E’s Table

Comparison of Virtual-Circuit and Datagram Networks

Comparison of datagram and virtual-circuit networks

The IP Routing Process• IP address, Mac address

Routing ProtocolsRouting

Static Routing

Dynamic Routing

IGP EGPProtocols: BGP

Distance VectorProtocols: RIPv1&2, IGRP

Link StateProtocols: OSPF, IS-IS

HybridProtocols: EIGRP

Default Administrative

DistanceRoute Source Default ADConnected interface

0

Static route 1EIGRP 90IGRP 100OSPF 110RIP 120External EIGGRP 170Unknown 255(this route will never be

used)

(a) A network. (b) Input from A, I, H, K, and the new routing table for J.

Distance Vector Routing

The Count-to-Infinity Problem

The count-to-infinity problem

Link State Routing1. Discover neighbors, learn network addresses.

2. Set distance/cost metric to each neighbor.

3. Construct packet telling all learned.

4. Send packet to, receive packets from other routers.

5. Compute shortest path to every other router.

Building Link State Packets

(a) A network. (b) The link state packets for this network.

Distributing the Link State Packets

The packet buffer for router B in previous slide

RIPv1 RIPv2Distance vector Distance vectorMaximum hop count 15 Maximum hop count 15Classful ClasslessBroadcast based Uses Multicast 224.0.0.9No support for VLSM Supports for VLSMNo Authentication Allow for MD5

authenticationNo support for discontiguous networks

Supports discontiguous networks

Characteristic OSPF RIPv2 RIPv1Type of protocol Link state Distance

vectorDistance vector

Classless support Yes Yes NoVLSM support Yes Yes NoAuto summarization

No Yes Yes

Manual summarization

Yes No No

Discontiguous support

Yes Yes No

Rout propagation Multicast on change

Periodic multicast

Periodic broadcast

Characteristic OSPF RIPv2 RIPv1Path metric Bandwidth Hops HopsConvergence Fast Slow SlowPeer authentication

Yes Yes No

Hierarchical Yes (using area)

No (flat only) No (flat only)

Update Event triggered

Rout table updates

Rout table updates

Rout computation

Dijkstra Bellman-Ford Bellman-Ford

Hierarchical Routing

Hierarchical routing.