08-13-2008 08:38 PM - edited 03-03-2019 11:08 PM
The customer router has a two ethernet connections to two routers with same ISP. All three run in same AS. The connecitivty is via BGP nothing else. The customer router is receiving a default route from both ISP routers. It is like a backup. One router is preferred over the another using the MED received by the customer router.
The ISP routers have a serial connection out to the internet. The problem is the ISP main router serial interface (which is one of the customer router is connected) keep flapping. The customer router connection to the ISP routers are stable becuase of ethernect connection. Now I need somekind of solution that if the ISP router serial link is flapping We can control the customer router to switching back to the ISP main router till the link is stable.
I was thinking using Route dampening but it is not goona help becuase we are receiving only one default route.
Hope you guys can under stand what I am tyring to say here.
Tks
08-13-2008 09:37 PM
have u tried conditional route
in other words
if the route to a spisific destination availabe then install do this route map not use the default config
this is the idea behind it
see this link
http://www.cisco.com/en/US/tech/tk365/technologies_configuration_example09186a0080094309.shtml
good luck
please, if helpful rate
08-16-2008 02:07 AM
IP SLA may help you also.
Here's how to do it
ip sla 1 < The number 1 here is arbitrary, used only to identify this sla. It is otherwise knows as the operation number>
icmp-echo 192.168.1.1< 192.168.1.1 is a ISPs WAN interface that responds to pings out on the internet>
timeout 500 < This is how long to wait for a response from the ping>
frequency 3 < This is the repeat rate for the SLA>
ip sla schedule 1 start-time now life forever < This command says "start SLA 1 now and keep it running forever>
track 1 rtr 1 reachability < This comand creates the track object "1" and monitors the SLA 1>
now for the routing, we need to change the default route and associate it with the tracker
and then put it back with the tracking
ip route 0.0.0.0 0.0.0.0 x.x.x.x track 1
Then we need to add our secondary route
ip route 0.0.0.0 0.0.0.0 x.x.x.x 10
Now when the ping to 192.168.1.1 fails the primary route is removed and the secondary route with the higher metric becomes the default. The route will be reinstated when the connectivity is restored.
Here is the reference to the Cisco IP SLA documentation
http://www.cisco.com/en/US/products/ps6350/products_configuration_guide_chapter09186a0080441845.html
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