Routing

Hi All,

Assume you have 2 routers J series or MX and you need to peer BGP with an ISP who will only peer with 1 IP.

Is it possible to setup VRRP on the public side and have the provider peer with the VRRP address.  Assumming a failure would happen BGP would reconverge but would this work or is this a terrible terrible idea?

Thanks

Hello,

Yes, it is possible. Such scenario is discussed in JNCIP Study Guide chapter 6

http://www.juniper.net/us/en/training/certification/JNCIP_studyguide.pdf

HTH

Thanks

Alex

Hi,

Yes it is possible.

I also found the example of what you are asking on this article:

BGP and VRRP Failover.

http://www.vyatta.org/node/755

VRRP is a LAN protocol. The Routers that you configure as VRRP routers communicate via a switch. I am hard pressed to see how you make it work if the two CISCO routers are configures with the same IP address. 

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@lyndidon wrote:

VRRP is a LAN protocol. The Routers that you configure as VRRP routers communicate via a switch. I am hard pressed to see how you make it work if the two CISCO routers are configures with the same IP address. 

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That's a fundamental function of VRRP -- only the active/master of the VRRP pair is going to respond to the configured IP.

When situation is normal, the preferred router will "own" the VRRP IP and establish the BGP session with the upstream peer and the backup router will sit quietly.  In a failover situation, the backup router will take over ownership of the VRRP IP and re-establish the BGP session.

Thanks everyone.  That was the answer I was looking for.  I can do it but it must re-establish BGP on failover (expected).

Hello,

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@keithr wrote:

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When situation is normal, the preferred router will "own" the VRRP IP and establish the BGP session with the upstream peer and the backup router will sit quietly.  In a failover situation, the backup router will take over ownership of the VRRP IP and re-establish the BGP session.

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I'd be careful with verb "own" and its derivatives in context of VRRP. It has a special meaning:

IP Address Owner       The VRRP router that has the virtual router's
                          IP address(es) as real interface address(es).

 http://www.ietf.org/rfc/rfc3768.txt

http://tools.ietf.org/html/rfc5798

"Own" in context of VRRP means "have this IP configured on the interface", not "respond to traffic addressed to this IP".

HTH

Thanks

Alex

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@aarseniev wrote:

Hello,

 

I'd be careful with verb "own" and its derivatives in context of VRRP. It has a special meaning:

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Alright... but I *did* use the quotes around "own" to signify it was a bit of a liberty with the definition of "own."

"Answers for" or "Responds to ARP for" would be more strictly correct than "own" in this case, yes, but I find that "own" gets the high-level point across.  Pedantic details obviously would require more exactness.

Of course we could further confuse the matter by bringing HSRP, VRRP-E, GLBP, etc., into the mix.

Hi Guys,

How long it will takes the BGP to re-established when the master switch to backup?

Thanks,

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@sanditehendi wrote:

Hi Guys,

 

How long it will takes the BGP to re-established when the master switch to backup?

Thanks,

 

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re-established sessions most of the time within 30 seconds, but depends on the timeout configured on the other side. also exchanging and learning the advertised routes can take some time, depending on how many routes... etc etc