Strange Behavior in CIsco6506 with HSRP

nafrasiyabov · ‎02-26-2009

HI everybody!

We have 2 Cisco6506 with HSRP running on them. For some interfaces the 1st one is active, for some interfaces 2nd one is active. You see that we do load balancing between them like this, and of cource have some redundancy. Some days ago i discover some strange behavior on second one. i attached the diagram, of cource its a logical diagram from there you can see which interface is active and which is standby. here is a problem: traffic from server which is sitting in vlan 40 should go through Second 6506 to First 6506 and get to Server that sitting in vlan 30.. and vice versa... but some days ago i checked the MRTG diagram and saw that traffic is goes through standby interface also.. And i sniff traffic on 2nd6506 and some traffic really going trough this interface. But how is it possible if this interface in other side is in Spantree Alternate state? and also i checked that there is NO mac entry in this interface ( sh mac-address interface gig x/y)! What is the cause is this misbehavior ? Anybody has any idea?

thanks is advance for your time and for your reply:)

hxxp://img408.imageshack.us/img408/5156/netprob.jpg

glen.grant · ‎02-27-2009

Unless the other side is in an actual spanning tree blocked state traffic can go out that side for a particular vlan. That being said the device should go out the active hsrp side unless the server's default gateway is incorrect and is not pointed to the hsrp virtual ip address but is instead pointed at the standby side actual address as its gateway . Just one scenario .

nafrasiyabov · ‎02-27-2009

hm..i dont get your point..the gateway default ip is virtual hsrp address, and the other side that connects to the standby switch is in blocked state.. what can be problem ?