Bridging on Router sub-interfaces

fsebera · ‎08-14-2012

Hi,

I need help with bridging 2 subinterfaces; F0/0.301 and F0/0.302 on a single router.

The router interfaces with a Cisco 2960 (LAYER-2) switch.

QUESTION is, does a Cisco router support bridging on subinterfaces on the same physical interface?

Currently this is NOT operational

Spaiing-tree on F0/0.301 and F0/0.302 is down, switch side is forwarding for both Vlans.

show ip interface brief shows up/down status of F0/0.301, F0/0.301 and BVI6 is down/down

Thanks for ANY help!!!

Frank

:

SETUP:

bridge irb

!

Interface F0/0

no ip address

!

F0/0.6

Desc MGT

encapsulation dot1q 6 native

ip addresss 192.168.1.7 255.255.255.0

!

F0/0.301

encapsulation dot1q 301

bridge-group 6

!

F0/0.302

encapsulation dot1q 302

bridge-group 6

!

interface BVI6

ip address 172.16.3.1 255.255.255.0

!

bridge 6 protocol ieee

bridge 6 route ip

!

fsebera · ‎08-16-2012

Ok this is very strange.

For all of you that provided help with my problem, THANK YOU!!!

:

As you can see, all responce's have been removed from this question - not sure why.

:

The config presented above does now work (the issue was an err-disable switch port) and has now been corrected.

Thanks again your assistance.

Frank

anas.awad · ‎01-12-2016

Hello Frank,

I know its old and 3 years ago, but I need help and still don’t know how to configure IRB, I

I am trying to make a vlans/subnet span across multiple (three) subinterfaces (i have three vlans configured on a layer 2 switch) using IRB. (Ref.: http://www.cisco.com/c/en/us/support/docs/lan-switching/integrated-routing-bridging-irb/17054-741-10.html)

three layer 2 switches are directly connected to 4431 router, each physical interface on a router have three sub interfaces and tagged, assigned to a bridge group.

However, my setup does not seem to work properly:

What am I doing wrong? Can someone please help find a solution?

I have been Google'd and searched for the answer to these questions, but I cannot find a simple answer.

Here is the configuration I am currently using on the router

bridge irb
!
interface Ethernet0/0
no ip address
full-duplex
!
interface Ethernet0/0.10
encapsulation dot1Q 10
bridge-group 1
!
interface Ethernet0/0.11
encapsulation dot1Q 11
bridge-group 2
!
interface Ethernet0/0.255
encapsulation dot1Q 255
bridge-group 3
!
interface Ethernet0/1
no ip address
full-duplex
!
interface Ethernet0/1.10
encapsulation dot1Q 10
bridge-group 1
!
interface Ethernet0/1.11
encapsulation dot1Q 11
bridge-group 2
!
interface Ethernet0/1.255
encapsulation dot1Q 255
bridge-group 3
!
interface BVI1
ip address 10.111.10.254 255.255.255.0
!
interface BVI2
ip address 10.111.11.254 255.255.255.0
!
interface BVI3
ip address 172.16.255.254 255.255.255.0
!
bridge 1 protocol ieee
bridge 1 route ip
bridge 2 protocol ieee
bridge 2 route ip
bridge 3 protocol ieee
bridge 3 route ip

########################################

Switch 1

interface FastEthernet0/0
switchport mode trunk
interface Vlan1
no ip address
!
interface Vlan255
ip address 172.16.255.1 255.255.255.0
!
ip default-gateway 172.16.255.254

########

SW2

interface FastEthernet0/0
switchport mode trunk

interface Vlan1
no ip address
!
interface Vlan255
ip address 172.16.255.2 255.255.255.0
!
ip default-gateway 172.16.255.254!

alexey.gosha · ‎04-22-2016

Hello anas.awad,

I have such problem, I need to transfer config from my old 3825 to the new 4431 router running with (X86_64_LINUX_IOSD-UNIVERSALK9-M), Version 15.5(3)S2

Bridge-group command not available for me to configure it on subinterface.

I want to bridge each subinterface with corresponding vlan on the my network, like Vlan1 = bridge 1 and so on.

interface Ethernet0/1.10
encapsulation dot1Q 10
bridge-group 1

Also I can't configure as "bridge 1 protocol ieee". I only have these protocols:dec, ibm, vlan-bridge.

How did you get this on your 4431?

anas.awad · ‎04-22-2016

Hello Alexey,

I never have been worked before on IRB so the above configuration i have attached was created on a lab simulation for precaution, it works after i had removed the default gateway and configured a static routes on the switches.

But the real dilemma here is once i have received the 4000 series routers for the implementation i could not find the all needed commands for bridge features like ieee protocol was not supported so i had to change the design and connect the switches back to back then use only one physical interface on router, configured sub-interfaces and tagged them then router all my subnets.
I have looked and searched but with no results.

i wish i can help you more, you can try and check the below

1. http://www.cisco.com/c/en/us/support/docs/lan-switching/integrated-routing-bridging-irb/17054-741-10.html

2. http://www.cisco.com/c/en/us/td/docs/ios/12_2/ibm/configuration/guide/fibm_c/bcftb.html