HSRP Two 6509 + 20 Vlans

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Hello All

If I have two 6509's running as our core network and each 6509 is the active switch for half of the vlans. The 6509's are connect via 4 ten gig L2 port channel. My question is, when configuring HSRP is it necessary to enable port tracking in this situation. From what I have read HSRP will not failover automatically during an interface failure unless port tracking with decrement and preempt are enabled within each Vlan SVI. In addition, which ports would need to be tracked? The L2 port channel connecting to the second 6509? The SVI Vlan 10 on each 6509? I understand using port tracking when you have redundant Internet connections, but I am unclear on how to set up port tracking in a situation where vlan's are spread across switches.. Thank you for all input

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Lei Tian Thu, 04/01/2010 - 20:54
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Hi,


If your two 6500s are peering each other as some L3 routing protocol, then you dont need to have tracking interface here. You just need to have preempt configured, so in case of the HSRP active fails and comes back later, it can take the active role back.


HTH,

Lei Tian

Jon Marshall Fri, 04/02/2010 - 01:15
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From what I have read HSRP will not failover automatically during an interface failure unless port tracking with decrement and preempt are enabled within each Vlan SVI


This is not the case. If an interface fails then HSRP will automatically failover. Tracking is used where an interface not running HSRP fails and because of this you want your clients to go to a different L3 switch so you make the priority on the active switch lower so it will failover.


Jon


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glen.grant Fri, 04/02/2010 - 05:35
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  In the situation  you are indicating where you have 2 6509's with switches between them and you have them peered then the only time I can see hsrp ever failing over would be if the primary side 6509 fails . I don't see a  reason to track anything in your situation.

Ganesh Hariharan Fri, 04/02/2010 - 05:48
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Hello All

If I have two 6509's running as our core network and each 6509 is the active switch for half of the vlans. The 6509's are connect via 4 ten gig L2 port channel. My question is, when configuring HSRP is it necessary to enable port tracking in this situation. From what I have read HSRP will not failover automatically during an interface failure unless port tracking with decrement and preempt are enabled within each Vlan SVI. In addition, which ports would need to be tracked? The L2 port channel connecting to the second 6509? The SVI Vlan 10 on each 6509? I understand using port tracking when you have redundant Internet connections, but I am unclear on how to set up port tracking in a situation where vlan's are spread across switches.. Thank you for all input

Hi,


With your setup and two 6509 are connected via 4 Gig links , you don't require any tracking to be configured but preemption configuration will be useful with your setup as if primary goes down then only the backup comes into picture,so preempt can give the primary state to primary once it is up.

I don't think you require tracking configuration with your current setup.


Hope to Help !!


Ganesh.H


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Thank you for all of the wonderful responses!



If I understand everyone correctly. Tracking is only used for L3 interfaces or interfaces connecting to downline devices. HSRP "should" notice if one of the vlan's has crashed/down and automatically change to the standby 6509 within 3 failed helllo messages?. I am attaching part of the vlan config from each 6509.  From this configuration preempt is used on the active 6509 only. If the standby is currently the active 6509 for a certain vlan, once the active router has come back up will it automatically take over as being the active router?



Core A
interface Vlan10
description
ip address 10.XX.XX.2 255.255.254.0
standby 99 ip 10.XX.XX.1
standby 99 priority 110
standby 99 preempt delay minimum 120
!
interface Vlan19
description
ip address 10.XX.XX.2 255.255.255.0
standby 99 ip 10.XX.XX.1
standby 99 priority 110
standby 99 preempt delay minimum 120


Core B
interface Vlan10
description
ip address 10.XX.XX.3 255.255.254.0
standby 99 ip 10.XX.XX.1
standby 99 priority 109
!
interface Vlan19
description
ip address 10.XX.XX.3 255.255.255.0
standby 99 ip 10.XX.XX.1
standby 99 priority 109

Jon Marshall Fri, 04/02/2010 - 08:09
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Thank you for all of the wonderful responses!



If I understand everyone correctly. Tracking is only used for L3 interfaces or interfaces connecting to downline devices. HSRP "should" notice if one of the vlan's has crashed/down and automatically change to the standby 6509 within 3 failed helllo messages?. I am attaching part of the vlan config from each 6509.  From this configuration preempt is used on the active 6509 only. If the standby is currently the active 6509 for a certain vlan, once the active router has come back up will it automatically take over as being the active router?




Correct, preempt is only needed on the normally active interface so it can resume control.


Tracking is not needed in this case.


Jon

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