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Sunday, October 28, 2012


Here is a scenario where I had a Cisco 8xx ISR device which connected to an ADSL line, now the ADSL is no more than 100Mbps (actually 15/1Mbps) so i connected it to port FE 8, which is marked with B which leave me with 8 more FE ports and 1 GE port.

The problem is that the all 8 FE ports are Ethernet switch ports where the GE port is WAN port, so how can I utilize the GE port and make it part of my LAN?

If I have a NAS server which I want to connect to the GE port for using 1000Mbps interface and still be part of my network?

The solution is using bridge-group which allows me to connect different ports/interfaces into the same broadcast domain.

First configure bridge-group on the router:
bridge 1 protocol ieee
bridge 1 route ip

Then I had to remove all configurations from VLAN 1 and to configure only the following:
interface Vlan1
 no ip address
 bridge-group 1

Configure the same on the GE port:
interface GigabitEthernet0
 no ip address
 load-interval 30
 duplex auto
 speed auto
 bridge-group 1

Then create a BVI (Bridge Virtual Interface) which bond L3 configuration for this bridge-group:
interface BVI1
 ip address
 no ip redirects
 no ip unreachables
 no ip proxy-arp
 ip nat inside
 load-interval 30

The result, Marked with A:
 The GE port is part of the broadcast domain of VLAN 1 which configured on all 8 FE ports.

1 comment:

  1. Great efforts put it to find the list of articles which is very useful to know, Definitely will share the same to other forums.
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