[j-nsp] PIM adjacencies between VRRP virtual interfaces

[Robert Walton]

Niels/All, 

	I'm hoping that i can, unforunately i've inherited an architecture whereby vrrp is in use. So, an open question again, can the adjacencies establish between the logical interfaces when vrrp is configured?

For example:

If I have two pairs of routers (1A,2A and 1B, 2B) facing each other on the same VLAN, both pairs of routers are running vrrp between them such that we have effectively two virtual interfaces (vrrp-if A and vrrp-if B) facing each other. 

router 1A   ------------  Router 1B
			|
	vrrp-if A	|     vrrp-if B
			|
Router 2A	------------  Router 2B

		    vlan x

If i was to enable PIM on the respective interfaces would the adjacencies be formed between the logical interfaces on each respective router? i.e. would the logical interfaces respond to the PIM hello packets even if vrrp is configured on thye interface? If this is the case then i would assume that i would have no problems with multicast forwarding (dense-mode or sparse) as the dependent information required to undertake this is derived from the PIM communication itself so assuming that the adjacencies are established then it should be ok (?)

Also, is the same applicable to IGMP?

Regards,
Rob

-----Original Message-----
From: Niels Bakker [mailto:niels=juniper-nsp at bakker.net]
Sent: 06 September 2004 21:04
To: juniper-nsp at puck.nether.net
Subject: Re: [j-nsp] PIM adjacencies between VRRP virtual interfaces


>>> Forming peering relationships based on the Virtual IP address is
>>> not supported for any routing protocol.
>> ..except for BGP (JNCIP Study Guide, chapter 6, p.493-494)

* pgoyette at juniper.net (Paul Goyette) [Mon 06 Sep 2004, 15:44 CEST]:
> There is no exception for BGP as far as I know.  The JNCIP study
> guide is not a statement of what is supported, although it may
> be a statement of what happens to work today.

Indeed.  VRRP is unsuitable for anything involving state.  Sure you can
do BGP to a virtual address but sessions will flap, causing routing
instability throughout your network (or possibly the world if you're
directly forwarding a prefix to your upstreams).

I'm not sure about PIM adjacencies, though.  They have a way of allowing
to be established into only one direction.  Why can't you (the original
poster) have two PIM neighbours active?


	-- Niels.

-- 
_______________________________________________
juniper-nsp mailing list juniper-nsp at puck.nether.net
http://puck.nether.net/mailman/listinfo/juniper-nsp

________________________________________________________________________
This email and any files transmitted with it are confidential and
intended solely for the use of the individual or entity to whom they
are addressed. If you have received this email in error please notify
security at ffastfill.com

This email has been scanned for all viruses by the FFastFill Email
Security System.
________________________________________________________________________