strange Routing of vlans in 6509

[g.shashank]

Hi

1. We have two 6509 switches with msfc.

one for routing odd vlans and other for routing even vlans.

2. When I give a trace route from odd vlan ( ex vlan 3 ) I reach the gateway of even vlan then the router interface.

3. The same trace from even vlan reaches even vlan gateway then hits odd vlan gateway then router interface.

4. Load balancing in l2 is done by spantree priority. and in L3 my standby priority.

5. Created two standby group. 1--odd

2--even vlan.

What could be the problem

regards.

shashank

[jbohla]

I think some more information is needed to find what is happening. When you say, you are tracing from odd or even vlan, it is not clear whether you are tracing from the switch themseleves or a device attached to that vlan. It is also necessary to know to which address or vlan to which you are attempting to do a traceroute. I would suggest that you first try to find on which link between the switches does the traffic flow for odd and vlans. This will depend on spanning tree if you have configured trunking between them and allowing all the vlans to be carried on the trunks. If your image supports, you can use the 'l2trace' command to find your layer2 topology. You can also find out who is the active HSRP router and depending on these, you should be able to understand the behavior.

[rlotwala]

Hello Shashank,

Are you running HSRP? If yes, then you may be seeing IP address from that Interface VLAN. Also you've mentioned that you've configured VLAN's by priority. Are you tracking VLAN? For example "standby track VLAN XXX", which monitors VLAN XXX. Tracking can also be configured same as Priority statement.

For example:

CORE1 Configuration

interface Vlan101

ip address x.x.x.x x.x.x.x

standby priority 105

standby ip x.x.x.x

tandby preempt

tandby track vlan XXX

interface Vlan100

ip address x.x.x.x x.x.x.x

standby ip 10.240.100.3

standby preempt

CORE2 configuration

interface Vlan101

ip address x.x.x.x x.x.x.x

standby ip x.x.x.x

standby preempt

interface Vlan100

ip address x.x.x.x x.x.x.x

standby priority 105

standby preempt

standby track vlan YYY

I hope this is useful to you . Thanks.

Raj

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