Issues configuring IRB/BVI on router subinterfaces

Nikolaos Milas · ‎06-05-2015

Hello,

I am trying to make a vlan/subnet span across multiple (three) subinterfaces (each on a different physical interface) using IRB. (Ref.: http://www.cisco.com/c/en/us/support/docs/lan-switching/integrated-routing-bridging-irb/17054-741-10.html)

However, my setup does not seem to work properly: a device configured on VLAN 10 on interface G0/1.10 responds, while another device configured on VLAN 10 on Fa1/1.10 does not.

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

Here is the configuration I am currently using on the router:

bridge irb
bridge 1 protocol ieee
bridge 1 route ip

interface GigabitEthernet0/1.10
 encapsulation dot1Q 10
 bridge-group 1

interface FastEthernet1/0.10
 encapsulation dot1Q 10
 bridge-group 1

interface FastEthernet1/1.10
 encapsulation dot1Q 10
 bridge-group 1

interface BVI1
 ip address 10.201.0.1 255.255.254.0
!

Thanks in advance,
Nick

Nikolaos Milas · ‎06-05-2015

Actually the above problem was caused by an intermediate switch not allowing trunking for the particular VLAN. (Oh, those SB Switches...)

I'll see if everything else works as expected...

Regards,
Nick

anas.awad · ‎01-12-2016

Hello ,

I know its old and 7 months ago, but I need help and still don’t know how to configure IRB,

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!