notes: RIP Default Routing, Route tagging

Default Routing

1. Generates and advertises an unconditional default route to neighbors

default-information originate

2. Using distribute-list with prefix list sending default routes

ip prefix-list DEFAULT seq 5 permit 0.0.0.0/0
!
router rip
distribute-list prefix DEFAULT out

3. using route-map advertising default route conditionally


ip sla monitor 1
type echo protocol ipIcmpEcho 204.12.1.254 source-interface
FastEthernet0/0
timeout 50
frequency 1
ip sla monitor schedule 1 start-time now
!
track 1 rtr 1
!
router rip
default-information originate route-map RELIABLY_TRACK_LINK_TO_BB3
!
ip route 169.254.0.1 255.255.255.255 Null0 track 1
!
ip prefix-list DUMMY_ROUTE_TRACKED_VIA_SLA seq 5 permit 169.254.0.1/32
!
route-map RELIABLY_TRACK_LINK_TO_BB3 permit 10
match ip address prefix-list DUMMY_ROUTE_TRACKED_VIA_SLA

note:

With this example an IP SLA instance is introduced into conditional default origination. The SLA instance checks reachability to BB3 via ICMP every five seconds, with a timeout of two seconds. The SLA instance is then called from an enhanced object, which is called from a static route. This link local route of 169.254.0.1/32 could be any arbitrary dummy prefix. The dummy prefix is then called from a route-map which is tied to the default route origination. Therefore if R4 loses ICMP reachability to BB3 the default route is withdrawn. With the network properly functioning R4 advertises its default route to R5.


Route Tagging

-used in redistribution, then in a route-map

verification:

show ip rip database