Subject: [VRRP] Need info reg interface IP used as VIP in VRRP

From: "Ramya Shekar (rashekar)" <[email-masked]>
Date: Sat, 27 Oct 2007 17:30:53 +0530

Hi all,
 
Can anyone explain how the behavior of VRRP is when interface ip is
configured as a VIP?
 
In particular, I need this scenario. 
 
    * Router A and router B exist with VRRP configured in them.
    
    * VR ID is 1 & VIP is interface ip address of A in both routers A
and B and hence A is Master with priority 255 & B is Backup.
    
    * Through object tracking, priority of A is reduced from 255 (say
the case being another interface in router A going down & by tracking,
the priority of VR 1 in router A goes down).
 
    *  In this case, will A be preempted by B and thus will B become the
master of the VIP which is the same as one of the interface ip addresses
of router A? Or will A continue to remain the Master as the VIP is its
interface IP address?
 
Thanks,
Ramya  
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---

From: "Stephen Nadas" <[email-masked]>
Date: Mon, 29 Oct 2007 11:18:50 -0500

Ramya,
To my understanding, if the interface address is also the VIP address,
that router owniing the IP address will always assume ownership,
essentially if the VIP is an interface address its priority is always
255 (A will keep mastership).   I suspect object tracking maybe somewhat
out of scope on this list, but, to my understanding, something external
to VRRP that trys, in response to some other event, to decrement the
VRRP priority for an VIP that is also an interface address cannot change
the VRRP priority.   Put another way, if you want to use techniques like
object tracking, I don't see how this can also use VIP addresses that
are also interface addresses.  I also don't see why it is necessary to
do so; I think you can do what you want without using interface
addresses. 
Steve    

________________________________

	From: Ramya Shekar (rashekar) [mailto:[email-masked]] 
	Sent: Saturday, October 27, 2007 8:01 AM
	To: [email-masked]
	Subject: [VRRP] Need info reg interface IP used as VIP in VRRP

	Hi all,
	 
	Can anyone explain how the behavior of VRRP is when interface ip
is configured as a VIP?

	    
	    * VR ID is 1 & VIP is interface ip address of A in both
routers A and B and hence A is Master with priority 255 & B is Backup.
	    
	    * Through object tracking, priority of A is reduced from 255
(say the case being another interface in router A going down & by
tracking, the priority of VR 1 in router A goes down).
	 
	    *  In this case, will A be preempted by B and thus will B
become the master of the VIP which is the same as one of the interface
ip addresses of router A? Or will A continue to remain the Master as the
VIP is its interface IP address?
	 
	Thanks,
	Ramya

---

From: "John Cruz (johcruz)" <[email-masked]>
Date: Mon, 29 Oct 2007 10:30:49 -0700

One implementation that supports object tracking (the implementation
calls
it as monitored-circuit) forces the VIP to not to be the interface IP
for exactly the
issue mentioned below by Steve.
 
John

	From: Stephen Nadas [mailto:[email-masked]] 
	Sent: Monday, October 29, 2007 9:19 AM
	To: Ramya Shekar (rashekar); [email-masked]
	Subject: RE: [VRRP] Need info reg interface IP used as VIP in
VRRP

	Ramya,
	To my understanding, if the interface address is also the VIP
address, that router owniing the IP address will always assume
ownership, essentially if the VIP is an interface address its priority
is always 255 (A will keep mastership).   I suspect object tracking
maybe somewhat out of scope on this list, but, to my understanding,
something external to VRRP that trys, in response to some other event,
to decrement the VRRP priority for an VIP that is also an interface
address cannot change the VRRP priority.   Put another way, if you want
to use techniques like object tracking, I don't see how this can also
use VIP addresses that are also interface addresses.  I also don't see
why it is necessary to do so; I think you can do what you want without
using interface addresses. 
	Steve    

		From: Ramya Shekar (rashekar)
[mailto:[email-masked]] 
		Sent: Saturday, October 27, 2007 8:01 AM
		To: [email-masked]
		Subject: [VRRP] Need info reg interface IP used as VIP
in VRRP

		Hi all,
		 
		Can anyone explain how the behavior of VRRP is when
interface ip is configured as a VIP?

		    * Router A and router B exist with VRRP configured
in them.
		    
		    * VR ID is 1 & VIP is interface ip address of A in
both routers A and B and hence A is Master with priority 255 & B is
Backup.
		    
		    * Through object tracking, priority of A is reduced
from 255 (say the case being another interface in router A going down &
by tracking, the priority of VR 1 in router A goes down).
		 
		    *  In this case, will A be preempted by B and thus
will B become the master of the VIP which is the same as one of the
interface ip addresses of router A? Or will A continue to remain the
Master as the VIP is its interface IP address?
		 
		Thanks,
		Ramya