10-13-2005 05:27 AM - edited 03-03-2019 12:23 AM
We currently have a 2948L3 Core switch which does the routing of our two class C ip schemes. I did this using a BVI. We have purchased a 3750L3 gigabit to replace a core switch at another location however it appears some of the bridging that was capable in the 2948L3 is no longer supported in the 3750 or the methods for implementing it has changes.
On the 2948 I configured it like so and everything works great.
ip subnet-zero
bridge irb
interface BVI1
description Kludge for 192.1.11.0/24 and 192.1.12.0/24 to exist within the same broadcast domain
ip address 192.1.12.1 255.255.255.0 secondary
ip address 192.1.11.248 255.255.255.0
no ip directed-broadcast
bridge 1 protocol ieee
bridge 1 route ip
I then add any port into bridge-group 1 and it can route between the two subnets.
The 3750L3 does not support bridge protocol ieee only vlan-bridge. Here is the config of the 3750
version 12.2
!
switch 1 provision ws-c3750g-24ts
ip subnet-zero
!
!
!
!
!
!
no file verify auto
spanning-tree mode pvst
no spanning-tree optimize bpdu transmission
spanning-tree extend system-id
!
vlan internal allocation policy ascending
bridge irb
!
!
interface GigabitEthernet1/0/1
no mdix auto
!
!
interface Vlan1
no ip address
bridge-group 1
!
interface BVI1
description BVI to allow 192.1.30.0/24 and 10.0.32.0/20 to exist
ip address 10.0.32.2 255.255.240.0 secondary
ip address 192.1.30.1 255.255.255.0
!
ip classless
ip route 10.0.32.0 255.255.240.0 BVI1
ip route 192.1.30.0 255.255.255.0 BVI1
ip http server
ip http secure-server
!
!
!
control-plane
!
bridge 1 protocol vlan-bridge
bridge 1 route ip
!
When i try to add any port to bridge group 1 other than vlan1 it tells me that
% command accepted but obsolete, unreleased or unsupported.
So my question is how would I allow two different subnets to work in the same broadcast domain on a 3750 like i did on the 2948. I've looked all over the cisco site but have not found any info on what config proceeds the bridge ieee command that i used on the 2948.
TIA
10-13-2005 07:40 AM
Brian
I do not have experience with the 3750 so I can not know for sure. But it looks to me that if you assign ports to VLAN 1 that they will be associated with bridge-group 1 and would allow two logical subnets to operate in the same broadcast domain.
Give it a try and let us know if it works.
HTH
Rick
10-13-2005 08:00 AM
Clearly most of the bridging commands are not supported on the 3750.
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