06-06-2013 10:33 PM - edited 03-04-2019 08:07 PM
Hi there,
I have an 877 router which has a DSL WAN interface. The DSL service at this site is unreliable, so the company have purchased a separate 3G router to be used as a backup. This device maintains 3G connectivity at all times and has a static IP on the internal subnet (for arguments sake let's say 10.0.0.253).
What I want to do with the Cisco router is to track the DSL interface and if it is up, install a default route pointing to it. If it is down, I want the default route to be the 3G router.
I am thinking the best way to do this is to set up a track and then set 2 default routes; one which is installed if the tracking is up, the other has a higher admin distance and points to the 3G router and thus should only be used if the track is down. For example:
track 10 interface Dialer0 ip routing
delay down 30 up 30
ip route 0.0.0.0 0.0.0.0 Dialer0 track 10
ip route 0.0.0.0 0.0.0.0 10.0.0.253 100
Is this likely to work or is there a better way to do it?
Thanks in advance
Solved! Go to Solution.
06-06-2013 11:19 PM
Hello, this configuration will work in your scenario. No further config required as far as I know.
This will track the interface as well as up up state and if it has a IP address.
If it fails it will switch over to your backup route which has a higher metric.
If you want faster switch over time you might want to tweak the delays?
Apart from this, all good :)
Sent from Cisco Technical Support iPhone App
06-06-2013 11:19 PM
Hello, this configuration will work in your scenario. No further config required as far as I know.
This will track the interface as well as up up state and if it has a IP address.
If it fails it will switch over to your backup route which has a higher metric.
If you want faster switch over time you might want to tweak the delays?
Apart from this, all good :)
Sent from Cisco Technical Support iPhone App
06-07-2013 09:28 AM
Hi,
I'm not sure about this and seems the config is incomplete. We usually setup our backup links using an IP SLA probe.
Sent from Cisco Technical Support iPhone App
06-09-2013 03:12 AM
Hi
Thanks for you reply. I think the IP SLA only is needed if I was trying to do a ping or http operation or something like that to verify connectivity. I have used this in the past like below to divert traffic one way or another based on next hop availability, but never on a WAN interface or with DSL.
track 10 ip sla 10
delay down 10 up 30
ip sla 10
icmp-echo 10.10.10.10
threshold 1000
timeout 1000
frequency 1
ip sla schedule 10 life forever start-time now
route-map example_route_map permit 10
match ip address example_access_list
set ip next-hop verify-availability 10.10.10.10 10 track 10
As the track command has the DSL option I don't think I need the IP SLA. I'm happy to be corrected though!!
06-09-2013 02:51 AM
Thanks, glad to know I'm on the right track!
06-07-2013 09:50 AM
Hi,
Another option would be to run HSRP between the two routers and track the status of the Dialer0 interface. If the interface goes down then decrement the HSRP priority on the DSL router so that the 3G router takes over as the default gateway.
HTH
Paul
Sent from Cisco Technical Support Android App
06-09-2013 02:55 AM
Thanks Paul. I forgt mention that the 3G router is not a Cisco router unfortunately and doesn't have HSRP support, or anything like it. If it were a Cisco router that would be really good though!
Cheers
Ché
06-09-2013 11:36 AM
No worries
Depending on the model it may support VRRP, which is a non-proprietary alternative to HSRP. Cisco routers support VRRP as well, so the same can solution can be applied using VRRP instead.
HTH
Paul
****Please rate useful posts****
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide