CCIE RS – L3 Tech – RIP and RIPng

RIP

Distance vector routing protocol
Hop count for routing metric

  • Max of 15 hops
  • Used to prevent routing loops
    • Split horizon
    • Route poisoning
    • holddown
  • 16 is infinite distance, route is considered unreachable

Hellos sent every 30 seconds

Timers

  • Update
    • 30 seconds
  • Invalid
    • 180 seconds
    • How long a route can be in routing table without being updated
    • After timer expires, routing entry wil be set to 16 and destination marked unreachable
  • Flush
    • 240 seconds
    • Time between route is marked unreachable and removal from the routing table
  • Holddown
    • Started per route entry
    • 180 seconds
    • Used in Cisco’s implementation

No concept of areas or boundaries

RFC 2453

UDP port 520

Multicast – 224.0.0.9

  • Sends entire routing table to all adjacent routers

Version 2 supports classless routing (CIDR)

Authentication – MD5 or text

Supports route tags

Split Horizon

  • Enabled by default
  • Reduce posibility of routing loops
  • Blocks information about routes from being advertised back on the interface they were learned on
  • May need to disable on an interface in hub/spoke scenario
  • Must disable if you want to use secondary addresses

 

Config

router rip
 version 2
 [no] auto-summary
 network [network]
 passive-interface default
 offset-list [acl] [in | out] {offset}
 timers basic [update, invalid, holddown, flush]
 [no] validate-update-source

interface [interface]
 ip rip send version [1 | 2]
 ip rip receive version [1 | 2]
 ip rip authentication key-chain [name]
 ip rip authentication mode [text | md5]
 [no] ip split-horizon

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_rip/configuration/xe-3se/3850/irr-xe-3se-3850-book/irr-rip.html


RIPng

RIP for IPv6. Based on the bellman-ford algorithm.

RFC 2080

Extension of RIPv2. Same hop count rule as RIP for IPv4

No update authentication – relies on the Authentication Header and IP encapsulating security payload

UDP port 521, each router sends and receives on this port for communicating RIPng

Multicast – FF02::9

Requirement – IPv6 routing must be enabled

ipv6 unicast-routing

interface [interface]
 ipv6 enable
 ipv6 rip [name] enable

ipv6 router rip [name]

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipv6/configuration/15-2mt/ipv6-15-2mt-book/ip6-rip.html

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