Forum Discussion
Rich_Pulver_794
Nimbostratus
NimbostratusBIGIP LTM PAIR with VLAN Groups
Not sure if this is the correct place for this or not, so please let me know if I need to go to another forum.
I am replacing a pair of Cisco CSS devices with a pair of BIGIP LTMs running 9.4.3. The CSSs are doing bridging to maintain "same ip network" for some apps that we run.
I have setup the LTMs in a lab with a vlan group for the virtual servers to pass traffic. There is a switch (Nortel) in front of the LTMs and a switch behind the LTMS. The ports on the switches are in the same VLAN as is the VLAN id for the vlan group. I have masquerade macs setup on the vlan group and the floating self IP.
Now for my question. What mode should I use for spanning-tree on the internal and external interfaces? With passthrough turned on I get a loop and broadcast storm.
If I turn on STP, no loop, but one LTM is always the root bridge, so when the LTM fails over, spanning tree is blocking the link to the new active unit.
I know people don't like VLAN groups and this situation is probably why, but I need to maintain a flat network for application purposes.
Any input would be greatly apprecaited. Thanks
- JRahm
Admin
You can disable bridging on standby in the vlangroup settings, and make sure you add the other unit's vlan group self IP to the local unit's proxy exclusion list. Once this is done, you can disable spanning-tree on the vlan group interfaces and the switch uplink ports. 
Rich_Pulver_794Ahhh, okay. I do have bridge in standby disabled on the vlan group, but I don't have the proxy exclusions. Thanks for the suggestion. I'll give it a shot. Thanks again.
