Redundancy (HSRP) and Routing Protocols

Unanswered Question
Nov 1st, 2009

Hi,


RIP in conjunction with HSRP doesn't use the virtual address. It always uses the physical address.If we have two routers running HSRP and facing a single link for

receiving updates , what's the best way to fit HSRP in this scenario (Assuming we want to have a single router acting for routing updates at a time)


**** I've injected higher metric to standby router but still standby is in charge of routing (the only difference is standby has higher address than the master)


Is there anyway to fix this?



Thx.

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Richard Burts Sun, 11/01/2009 - 19:04

Samir


Perhaps there are some aspects of your description and your environment that I do not understand clearly. Perhaps you can clarify the topology and the situation? If 2 routers are on a single link, are they connected by a switch? What else is on the switch?


It would also be helpful to know what is on the link connecting to the routers. Is there a router on the link? (I would assume so if there is RIP on the link) Are there devices on the link other than the other router?


Also I would like to know how you determine that the standby is in charge of routing? Is this routing of other subnets onto this link? Or is it routing of subnets from this link onto other links?


Until we understand the problem better we will not be able to answer your question whether there is a way to fix this.


HTH


Rick

ssg14 Sun, 11/01/2009 - 20:03

Hi Rick,


Thanks for your response,


Both routers are connected to a switch and the 3rd router (the carrier side) is also connected to that switch.


The rest on that switch has no importance (from routing perspective and are not even in the subnet of RIP/HSRP)


How do i determine that who in charge -->


if I trace from one of my endpoints through carrier, it hits the standby physical interface then goes to carrier.


Also manually configures priority for HSRP and also standby has got higher metric for RIP.


Appreciate

Samir

Jon Marshall Mon, 11/02/2009 - 04:25

Samir


HSRP is used for end device redundancy and not for routing protocols. So routing protocols such as RIP/EIGRP/OSPF always use the physical address rather than the HSRP virtual address.


If you want to use HSRP to route your traffic then you would use a static route pointing to the HSRP VIP and this would take precedence over your RIP learned routes.


Or you could use PBR to force the traffic to go to the next0hop you wanted.


Or you could try and influence the metrics of the routing protocol to influence which path traffic takes.


However all of the above are just making a relatively straightforward setup more complicated with no apparent benefit so i wouldn't recommend any of them.


Is there a reason you need the traffic to go only one way ?


Jon

Richard Burts Mon, 11/02/2009 - 05:11

Samir


Thanks for the additional information. It does help to explain what is going on. If the 2 routers are connected through a switch to another router, and if there are no end stations in that subnet, then I quite agree with Jon that I do not see much reason to run HSRP on those router interfaces.


When you talk about tracing through the routers it indicates that there is a LAN connecting the routers on another interface. Is this the case? If so, are you running HSRP on this other interface? (it makes much more sense to run HSRP on router interfaces where end stations are connected since this is what HSRP was designed to do)


How is the PC configured that you use for the tracing? What is its default gateway?


Perhaps it would help us if you would post the output of show standby from both routers.


HTH


Rick

ssg14 Mon, 11/02/2009 - 16:46

Thx Jon & Rick,


I removed the HSRP on WAN side and only playing with metric to have an active rotuer at a time.


HSRP gone to internal (LAN side)



Thx Again guys

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