Backup not working

[mbalasubramanian]

We are trying to configure fall backup for a 2611 router. Our main RF link WAN broadband radio with ethernet feed to router is connected with e0/0 )& e0/1 is connected with local network.WE have an additional BRI CARD which has to be configured as backup

.If the RF link goes down BRI0/0 has to dial & connect as backup link

Since the main WAN link is connected via ethernet to radio modem and then onto RF link..even if RF link goes down the interface(Ethernet to WAN)remains up

How do i configure the ISDN as backup in this scenario..we have observed that even if RF link goes down the ISDN doesnt dial out

Normmaly Under what circumstance/'s would a router abandon a route and take an alternate route(when both are static routes) and how do i configure backup in the above scebario

Thanks

[toerierz]

Have you got keepalives set on the WE router interface(s) ?

[Georg Pauwen]

Hello,

you could try to configure dialer watch. Here is the link to the Cisco site describing how to configure dialer watch:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fdial_c/fnsprt6/dcdbakdw.htm#1000969

Regards,

Georg

[mbalasubramanian]

Hi,

Under what circumstance is a primary static route abandoned ie deleted from route table

1)Interface down

2)line protocol dowm

3)Next hop down

Is it a combination of all the above or in our case since the WAN link is also ethernet interface/lineprotocol doesnt go down even though the RF link goes down(next hop is dwon) so why isnt the route deleted and static floating route suffice

Can dialer watch be configured between primary static and secondary static routes or is it the primary needs to be dynamic

regards and thanks

[prafuljaded]

Hi,

pls chk this link, it give you a comparison of different backup methods....

http://www.cisco.com/warp/public/123/backup-main.html

Rgds,

Praful Jaded

[mbalasubramanian]

Hi,

I can see the various methods for configuring a backup inteface

but my question is

Under what circumstance is a primary static route abandoned ie deleted from route table

1)Interface down

2)line protocol dowm

3)Next hop down

Is it a combination of all the above or in our case since the WAN link is also ethernet interface/lineprotocol doesnt go down even though the RF link goes down(next hop is dwon) so why isnt the route deleted and static floating route suffice

[vcjones]

As you have already determined, dialer watch and dial on demand require the ability to detect that a destination is no longer reachable. Routers typically do this by using a keep alive at the link level (which does not work for you because the Ethernet is still functional) and/or a routing protocol at the network level.

The common approach for this challenge is to use a Nexland Pro800 Turbo or equivalent home office box which detects link down using ping and http rather than a routing protocol. This allows providing high availability of Internet access using low cost "consumer grade" DSL and cable modem ISPs.

The cleanest way to do this using Cisco kit is to use BGP to a box on the other end of the wireless link to detect loss of communications. This use of BGP does NOT require an Autonomous System Number, but typically does require static IP address assignments. Cisco people have also talked about introducing a Nexland like ping functionality, but I could not find any references on the Cisco web site.

Good luck and have fun!

Vincent C Jones

www.networkingunlimited.com

[mbalasubramanian]

Hi,

Would that mean i cannot do a dialer watch using primary static route

regards

[mbalasubramanian]

hi,

WOuld that mean i cannot implement the same (dialer watch) using a primary static route....i would have to go in for some dynamic routing protocol on the primary link

thanks