Hi One interesting scenario here. Two core switches (with MSFC) running HSRP. Core 1 is the master for vlan 1, and core 2 is the master for vlan 2. Understand MSFC arp timer is 4 hours, but switch CAM timer is 300 seconds. So there will be one problem:
1. Client 1 (vlan 1) wants to talk to client 2 (vlan2). It will send one frame to client 2 using Core 1s mac address as the destination mac, because Core 1 is its gw. 2. Core 1 will check its routing table and forward the packet to client 2. Meantime, it will change the frames source mac address to its own mac and the des mac to client 2s mac address. 3. Core 2 will just simply switch the frame to client 2, because core 1 has done the routing. To core 2, its arp table and aft table wont contains client 1s mac address so far, since core 1 has translated the frames source mac address. 4. When client 2 wants to reply, it will send the replying packets to core 2. Core 2 will arp for client 1s mac address. When client 1 reply this arp request, core 2 will add its mac address to both its arp table and aft table. 5. this is working fine so far. 6. after 300 seconds, core 2s aft table time out. However its arp table is still valid, so it wont do any more arp request. When client 2 wants to talk to client 1, core 2 will do the routing correctly, but then flood the frames to all the switch ports. Is my theory correct? __________________________________________________ Do You Yahoo!? Yahoo! Sports - live college hoops coverage http://sports.yahoo.com/ Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=38635&t=38635 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
