RIPv2 Basics

While labbing on GNS3 using INE workbooks RIP protocol , I came accross some of these basic features that worth mentioning

1.  It is always a good idea to disable auto-summary since rip summarizes across classful network by default.

2.  Summary address is created per outgoing interface using “ip summary-address rip” command

3.  Since RIPv2 send updates to multicast address, if a task requires rip updates not to use unicast or multicast, then the rip process will have to use broadcast (just like RIPv1). This can be accomplished with “ip rip v2-broadcast” on rip interface mode.

4.  On the other hand, if a task requires RIPv2 updates to be sent as unicast packets ONLY to rip neigbors, then you need to use neigbor command under rip process to specify the neighbor. But HERE is a catch, with neighbor command, RIPv2 still sends multcast packets ANYWAY, hence the neighbor command must be combined with “passive-interface <intf_name>” Passive-interface command disables all RIP updates being sent on that interface but neighbor still send unicast to rip neighbor.

  • router rip
  • neighbor
  • passive-interface fa0/0

5.  RIPv2 supports both md5 & clear text authentication. This is configured by first creating key chain and then applying the key chain to a rip interface.

  • key chain r2r4
  • key 1
  • key-string sesano
  • int fa0/0
  • ip rip authentication mode md5
  • ip rip authentication key-chain r2r4

6.  Routes metrics (hop counts) can be modified with off-set list with acl matching the selected routes.

7.  Route filtering in RIP is commonly done with distribute-list and this can be combined with acl or prefix-list .

8.  If a secondary ip address is configured on interface, please note that RIP only advertises updates sourced from primary address.  To allow updates from secondary interface to be sent out on primary interface, disable split horizon on that interface or use “no validate update-source” on neighbor interface.

9.  RIPv2 supports 4 timers (update, holddown, invalid, flush) and out of these timers, holddown timer is not specified in the RFC (It is cisco specific).

About ccie4all
Hello, and welcome to the first post of my CCIE blog This blog has got one simple goal and that is to improve our skills in Cisco Networking field so we can become best engineers on a job market. Wordpress Blog information about the changes made to Gns3 BGP , MPLS and R&S CCIE labs. In order to access and download all provided materials and receive important updates from Gns3 BGP , MPLS and R&S CCIE labs under GNS3 tab in the main header please go ahead and subscribe to ! All other posts have not been affected and can be accessed at any given time. Enjoy ! Tom

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