IP SLA on Cisco 3750 switch to track static route (not default route)

[engmkhalifa]

Dears,

i wonder if i can make a backup static route for an existing link over wan using the below diagram

the Core Switch type is 3750 in both sides

i`m using only static routing for  all destination like

Core1:

ip route 192.168.8.0 255.255.255.0 172.10.10.30

Core2:

ip route 172.17.200.0 255.255.255.0 192.168.100.105

requirements is to track the reachibility for the core ip address from both sides & change the routing automatically to the backup tunnel line

[srikanth ath]

Hello,

Yes, such thing is possible using the IP SLA feature. Basically, you perform a test of rechability of the next hop using ordinary pings. If these pings fail, the route will be declared unusable even though the egress interface appears to be alive. That will allow the dynamic route to enter the routing table.

Assume that you are configuring this for a static route towards 10.0.0.0/8 and the next hop is 192.0.2.2 on your Fa0/0 interface. The complete setup would be:

ip sla 1 ! The IP SLA operation is defined here

icmp-echo 192.0.2.2

  frequency 10 ! The 192.0.2.2 is pinged each 10 seconds

  threshold 500 ! Pings over 500msec are considered delayed

  timeout 1000 ! Pings over 1000msec are considered timeouted

!

ip sla schedule 1 start-time now life forever ! The SLA operation is scheduled to run indefinitely

!

track 1 rtr 1 reachability ! Track object 1 will hold the result of the IP SLA 1 operation

!

ip route 192.0.2.2 255.255.255.255 FastEthernet0/0

ip route 192.0.2.2 255.255.255.255 Null0 2

! The previous two lines make sure that the 192.0.2.2 is either reached via Fa0/0 or is never reached

! This is to prevent successfully pinging 192.0.2.2 via some detour

ip route 10.0.0.0 255.255.255.0 192.0.2.2 track 1

Change the IP's accordingly to your setup.

Note: Make sure your IOS supports IP-sla, I guess advance service pack has this feature than other lan-base or any.

Regards,

srikanth

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