static route selection

Unanswered Question
May 7th, 2008

We have two provider for a same branch, what is the best way to configure a automatically route selection if primary link go off?

i am using only static routing.


thanks.


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bvsnarayana03 Wed, 05/07/2008 - 02:51

You may use floating static routes i.e. routes with diff AD. e.g.


ip route x.x.x.x y.y.y.y next-hop (primary route)


ip route x.x.x.x y.y.y.y next-hop 10(secondary route)


where 10 in second statement i the AD. So, as long as next-hop in the 1st route statemnt is reachable, it will be used. Once the next-hop cant be reached than second route will be used due to higher AD.

adriatikb Wed, 05/07/2008 - 02:57

what can i do if i have two routers for different providers?

guruprasadr Wed, 05/07/2008 - 03:13

HI, [Pls Rate if HELPS]


Unless & Until the route exits in the Global Roting table the secondary route will be preferred once the Primary is OFF.


There are no additional configuration required, the secondary static route with Higher AD will do your requirement.


In addition, refer link below and perform a task to create an IP SLA to ping the target address. This will help you to track the status of the Primary Connection to the remote gateway.


Refer Link below for Reliable static Routing Backup with Object Tracking:


http://www.cisco.com/en/US/docs/ios/12_3/12_3x/12_3xe/feature/guide/dbackupx.html#wp1087990


Hope I am Informative.


Pls Rate if HELPS


Best Regards,


Guru Prasad R

jay77jay77 Wed, 05/07/2008 - 23:12

Another simpler well known option would be to use HSRP with object tracking provide the WAN link is not Ethernet link.


HTH

Giuseppe Larosa Thu, 05/08/2008 - 01:50

Hello,

if the two providers connect to two different routers in your network you need to redistribute the branch site IP prefixes in your IGP taking care to make the primary path the preferred one for all internal routers. You may accept that the router connected to the backup link locally use the backup path (or you can use on it a floating static route with AD > [your IGP external routes AD]).

When the primary link fails all routers will install the routes injected by the router connected to the backup link in the IGP protocol.


Hope to help

Giuseppe

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