Routing Protocols and Concepts: Chapter 5 doc

Chapter 5 RIP version 1 Routing Protocols and Concepts quangkien@gmail.com 2 Topics  RIPv1: Distance Vector, Classful Routing Protocol  Background and Perspective  RIPv1 Characteristics and Message Format  RIP Operation  Basic RIPv1 Configuration  RIPv1 Scenario A  Enable RIP: router rip Command  Specifying Networks  Verification and Troubleshooting  Verifying RIP: show ip route  Verifying RIP: show ip protocols  Verifying RIP: debug ip rip  Passive Interfaces  Automatic Summarization  Modified Topology B  Boundary Routers and Automatic Summarization  Processing RIP Updates  Sending RIP Updates  Advantages and Disadvantages of Automatic Summarization  Default Route and RIPv1  Modified Topology C  Propagating the Default Route in RIPv1 RIPv1: A Distance Vector, Classful Routing Protocol  Background and Perspective  RIPv1 Characteristics and Message Format  RIP Operation 4 RIPv1: Distance Vector, Classful Routing Protocol  The first protocol used was Routing Information Protocol (RIP).  RIP still popular: simple and widespread support.  Why learn RIP?  Still in use today.  Help understand fundamental concepts and comparisons of protocols  such as classful (RIPv1) and classless (RIPv2) 5 Background and Perspective  RIP is not a protocol “on the way out.”  In fact, an IPv6 form of RIP called RIPng (next generation) is now available 6 Background and Perspective  Charles Hedrick wrote RFC 1058 in 1988, in which he documented the existing protocol and specified some improvements.  RFC 1058 can be found at http://www.ietf.org/rfc/rfc1058.txt 7 RIPv1 Characteristics and Message Format  Note:  The first version of RIP is often called RIPv1 to distinguish it from RIP version 2 (RIPv2).  However, both versions share many of the same features. When discussing features common to both versions, we will refer to RIP. When discussing features unique to each version, we will use RIPv1 and RIPv2.  RIPv2 is discussed in Chapter 7.  RIP characteristics:  Distance vector routing protocol.  Metric: hop count  Advertised routes with hop counts greater than 15 are considered unreachable.  Response messages (routing table updates) are broadcast every 30 seconds. (RIPv2 uses multicasts) 8 RIPv1 Characteristics and Message Format Next slide 9 RIPv1 Characteristics and Message Format 10 RIP Message Format: Route Entry  Each Route Entry (three fields):  Address Family Identifier (set to 2 for IP unless a router is requesting a full routing table, in which case the field is set to 0)  IP Address: Network address of an advertised route  Metric: How many hops to get to this network via this router (incremented by each router)  One RIP update can contain up to 25 route entries. [...]... show ip protocols Command Verifies that RIP routing is configured and running on Router R2 At least one active interface with an associated network command is needed before RIP routing will start 27 Verifying RIP: show ip protocols Command These are the timers that show when the next round of updates will be sent out from this router—23 seconds from now, in the example 28 Verifying RIP: show ip protocols. .. show ip protocols Command This information relates to filtering updates and redistributing routes, if configured on this router Filtering and redistribution are both CCNP-level topics 29 Verifying RIP: show ip protocols Command Information about which RIP version is currently configured and which interfaces are participating in RIP updates 30 Verifying RIP: show ip protocols Command Router R2 is currently... subnet mask 15 Enabling RIP: router rip Command R1# conf t Enter configuration commands, one per line End with CNTL/Z R1(config)# router ? bgp Border Gateway Protocol (BGP) egp Exterior Gateway Protocol (EGP) eigrp Enhanced Interior Gateway Routing Protocol (EIGRP) igrp Interior Gateway Routing Protocol (IGRP) isis ISO IS-IS iso-igrp IGRP for OSI networks mobile Mobile routes odr On Demand stub Routes... R in the output indicates RIP routes Because this command displays the entire routing table, including directly connected and static routes, it is normally the first command used to check for convergence Routes might not immediately appear when you execute the command because networks take some time to converge 23 Verifying RIP: show ip route Command R2# show ip route Codes: C - connected, S - static,... routing tables 2 A Response message is sent back by RIP-enabled neighbors If new route: Installs in routing table If existing route: Replace if better hop count Startup router then sends a triggered update out all RIP-enabled interfaces containing its own routing table so that RIP neighbors can be informed of any new routes 11 IP Address Classes and Classful Routing No subnet mask RIPv1: Classful routing. .. 192.168.1.0/24 [120/1] via 192.168.6.2, 00:00: 05, Serial0/0/0 R3# show ip protocols Routing Protocol is “rip” Routing Information Sources: Gateway Distance 120 192.168.6.2 Distance: (default is 120) Last Update 00:00:10 RIP has a default administrative distance of 120 When compared to other interior gateway protocols, RIP is the leastpreferred routing protocol Note: This is irrelevant... equal-cost routes to loadbalance Automatic summarization is discussed later in this chapter 31 Verifying RIP: show ip protocols Command Classful networks configured with the network command are listed next These are the networks that R2 will include in its RIP updates (with other learned routes) 32 Verifying RIP: show ip protocols Command RIP neighbors Gateway: Next-hop IP address of the neighbor that is sending... is irrelevant because you usually do not run multiple routing protocols in the same domain, and even if you did you can modify these AD values 13 Basic RIPv1 Configuration RIPv1 Scenario A Enable RIP: router rip Command Specifying Networks RIPv1 Scenario A Notice that this topology uses five Class C network addresses Remember, RIPv1 is a classful routing protocol We will see that the class of the network... No routing updates are sent until additional commands are configured no router rip To remove the RIP routing process from a device Stops the RIP process Erases all existing RIP configuration commands 17 Specifying Networks Router(config-router)# network directly-connected-classfulnetwork-address To enable RIP routing for a network, use the network command in router configuration mode Enter the classful... R3(config-router)# network 192.168 .5. 0 If you enter a subnet or host IP address, IOS automatically converts it to a classful network address For example, if you enter the command network 192.168.1.32, the router will convert it to network 192.168.1.0 20 Only directly connected classful network addresses! 21 Verification and Troubleshooting Verifying RIP: show ip route Verifying RIP: show ip protocols Verifying RIP: . Chapter 5 RIP version 1 Routing Protocols and Concepts quangkien@gmail.com 2 Topics  RIPv1: Distance Vector, Classful Routing Protocol  Background and. 6 Background and Perspective  Charles Hedrick wrote RFC 1 058 in 1988, in which he documented the existing protocol and specified some improvements.  RFC 1 058