Junosphere
This forum is intended for all discussions and questions relating to Junosphere. It is a branch-off from the former "Junos and Junosphere" forum, which is now titled "Junos".
Junosphere

Backup Router

‎07-23-2012 09:13 AM
While reading about the Backup Router configuration, I understood that it can serve as a fail-safe mechanism to provide connectivity to the router/switch, and also can be used as a quick way to forward packets before routing processes start. However, I've seen contradictory information in this post http://forums.juniper.net/t5/Junos-and-Junosphere/Backup-Router-Query/td-p/57162 where it was said that a backup router can't be used for forwarding traffic. On this page http://www.juniper.net/techpubs/en_US/junos/topics/task/configuration/backup-router-configuring.html it says "[...] Specify the address in the format network/mask-length so that the entire network is reachable through the backup router. By default, all hosts (default route) are reachable through the backup router." Could anyone clarify?
4 REPLIES 4
Junosphere

Re: Backup Router

‎07-24-2012 01:23 AM

Hi Cristo

 

The key is in the first sentence 

When a router or switch is booting, the routing protocol process (rpd) is not running

 Effectively this means, that while RPD is not running, the backup route will be in use. This would be true during boot up of the router and also when the routing engine is running as the backup routing engine. Once the RPD process is started however, this configured backup route is no longer valid.

Junosphere

Re: Backup Router

‎07-24-2012 04:15 AM
Thanks for your answer, Anton. I guess I should've been more specific about my question, I am interested in finding out if the router is able to perform packet forwarding between hosts that are using it as the default gateway and the rest of the network, using the backup router, before its own routing process starts, or when for whatever reason the routing process fails to start.
Junosphere

Re: Backup Router

‎07-24-2012 05:06 AM

I would say no. This command is used to give the Routing Engine some routing while RPD is down. The route will point of the management interface (typically FXP0 or similar interface) which is on the routing-engine itself. You can also not route traffic between this managment interface and the physical interfaces in the chassis.

Junosphere

Re: Backup Router

‎07-24-2012 05:26 AM
Great, cheers.