Fiber Link between two different root Switches

[hshaikh]

Hi All

We are in a process of merging two different companies and planned to connect new fiber link between the companies core switches.

1) If layer 3 interface is assigned , cant assign same IP address to both core switches at one end , as it will be specified as gateway on other end.

2) If layer 2 , how the two root switches can connect together to solve loops

3) or any other way.

Appreciate any help.

[Reza Sharifi]

Hi,

Not clear exactly what are you asking but if you want to connect them using layer-3 you can simply use a /30 and assign one IP to one switch and another one to the other switch.

192168.1.0/30

192.168.1.1 switch-a

192.168.1.2 switch-b

HTH

[hshaikh]

Hi  Reza , Thanks for the reply

There are two links between 4 switches. 2 core each at one side.

SW1 ( Company A )     to     SW1 ( Company B)

SW2 (company A)        to    SW2 (company B)

Here Core sw one side is running IRF , having same IP almost like vss in cisco.

We cant assign both switches interface in the core which connects to other side to same subnet as it overlaps.

Ten-gig 1/1/0/1 and Ten-gig 2/1/0/1 cant be same subnet on IRF side.

We can have the both interface in same vlan with interface IP address, but here my second query comes, the STP issues as both are set to core.

[Dennis Mink]

on a layer 2 link, you could play with the bridge priority of the two root switches, to make one preferred over the other  (leaving it to the MAC address as the decider is undesirable as it makes root election "unpredicatble")

[hshaikh]

Dennis , in short is only one root possible.

all vlans  and all routing are different in both sides.