HSRP Failove Issue

Unanswered Question

In HSRP we are facing some issue in implementation.

As for the network brief, Network Diagram and configuration of both the Cisco 3560 switch is attached here. There are two Cisco 500 switches at the edge, in these switches we have just given Management IP on the Vlan 1, there is no other Vlan configured, STP is enable on the switch there is no other configuration on the switch.

Description of Attached

• For Vlan 1 we have Cisco 3560 Switch - 1 assigned high HSRP priority.

• For Vlan 2 we have Cisco 3560 Switch - 2 assigned high HSRP priority.

• INTERVLAN routing is enabled.

Now as we have done the configuration on the switches as attached and mention above.

STP is seems working, as in normal condition it is blocking the port. Now as when we remove the cable from gig 0/22 from Cisco 3560 Switch - 2 (which was in forwarding mode in normal condition) the failover is not working, the network 10.10.0.0/24 becomes unreachable.

So are there any configuration changes required. Or any other think need to be look into this scenario.

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Dipesh Patel Sat, 10/04/2008 - 02:29

hi,

Cisco 3560 Switch - 1

interface Vlan1

ip address x.x.1.2 255.255.255.0

no ip redirects

no ip unreachables

standby 2 priority 125 preempt

standby 2 ip x.x.1.1

interface Vlan2

ip address x.x.2.2 255.255.255.0

no ip redirects

no ip unreachables

standby 2 priority 115

standby 2 ip x.x.2.1

Cisco 3560 Switch - 2

interface Vlan1

ip address x.x.1.3 255.255.255.0

no ip redirects

no ip unreachables

standby 2 priority 115

standby 2 ip x.x.1.1

interface Vlan2

ip address x.x.2.3 255.255.255.0

no ip redirects

no ip unreachables

standby 2 priority 125 preempt

standby 2 ip x.x.2.1

This type of Configuration should be.

Can you paste the configuration? Than Exact fault can be detected.

Dipesh.

glen.grant Sat, 10/04/2008 - 12:44

All your client workstations have their defalt gateway pointed the hsrp virtual ip ??? What state is hsrp in when you pull the cable , does it show switch 1 then as the hsrp active side ?

don't know much about the cat 500 , have never used them so can't help you there. Is the trunk between the cat 500 and switch 1 working correctly?

There is no configuration done for STP, it is in default....

There is no change in the HSRP state when i pull the cable....

Hey i have a point on this ?????

when i pulled out my cable out port at the edge switch will remain up as it is connected to FOT (Media Convertor) so the MAC table is not flushing out and due to this my frames are forwarded to the wrong port

Is it possible that due to this i have to wait 5 to 7 minutes to see the network reachable

in my testing i have given maximum 3 minutes to see the network go up ......

Regards,

Bhargav

dbroder Sun, 10/05/2008 - 20:41

Hi Bhargav. I think your problem is the media converter. You'll end up with a UDLD situation here -- one side of the link is down (the edge switch that you disconnected the cable from) and the other side is still up.

I believe the problem is because the switches cannot 'see' past the media converter -- which is really just a two port repeater with different media types.

I use media converters as well, and have to set the speed/duplex settings manually because the switches I use (3550s) will not negotiate speed/duplex over the media converters.

BTW, I'm assuming the 'cable' you describe disconnecting is the RJ45 copper ethernet, not the fiber optic cable -- although I think you'll still have the same HSRP problem either way.

I'm not positive about this being the problem, but I suggest trying this config without the media converters.

Good luck.

Darren.

dbroder Tue, 10/07/2008 - 20:40

Hi Bhargav. I understand what you mean ... I have the same problem on my campus as well. I guess what I'm saying is that because you are using media converters, you may not be able to solve this if these media converters are the root problem.

I hope I'm wrong in this case, but it seems like your switches believe the link is still up/good because the switch cannot 'see' past the media converter.

Let me know if I'm wrong! :)

There may be a way around this problem that I'm not aware of... I'd like to know how to fix it too!

Darren.

Dipesh Patel Tue, 10/07/2008 - 21:57

Hi Bhargav,

Sorry Yaar,

I was out side the site and can't reply.

Ya, Darren is right ....

Here you say that if you unplug cable from gi0/22 Media Converter Eth Port will be down but the Fiber Port will be up and hence at the end other side SWitch - 2 will remain UP ( In the case if Fibercable between media converter is cut the same senario will be ). Now This SW STP will not changes as it can't find any changes in topology hence Gi0/2 of SWitch will remain forwarding mode but actually is not. That may be the problem.

In this situation you check the spanning tree detail on Swtich 2 that which port is in forwading mode.

Dipesh,

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