Configuring Irb; Chapter 12 Configuring Irb - Cisco ONS 15454 SDH Configuration Manual

Configuring IRB

Before configuring IRB, consider the following:
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Configuring IRB
The process of configuring integrated routing and bridging consists of the following tasks:
1.
2.
3.
4.
5.
When you configure the BVI and enable routing on it, packets that come in on a routed interface destined
for a host on a segment that is in a bridge group are routed to the BVI and forwarded to the bridging
engine. From the bridging engine, the packet exits through a bridged interface. Similarly, packets that
come in on a bridged interface but are destined for a host on a routed interface go first to the BVI. The
BVI forwards the packets to the routing engine that sends them out on the routed interface.
To configure a bridge group and an interface in the bridge group, perform the following procedure,
beginning in global configuration mode:
Command
Step 1
Router(config)# bridge bridge-group
protocol {ieee | rstp}
Step 2
Router(config)# interface type number
Step 3
Router(config-if)# bridge-group
bridge-group
Step 4
Router(config-if)# end
Cisco ONS 15454 and Cisco ONS 15454 SDH Ethernet Card Software Feature and Configuration Guide, R8.0
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The default routing/bridging behavior in a bridge group (when IRB is enabled) is to bridge all
packets. Make sure that you explicitly configure routing on the BVI for IP traffic.
Packets of unroutable protocols such as local-area transport (LAT) are always bridged. You cannot
disable bridging for the unroutable traffic.
Protocol attributes should not be configured on the bridged interfaces when you are using IRB to
bridge and route a given protocol. You can configure protocol attributes on the BVI, but you cannot
configure bridging attributes on the BVI.
A bridge links several network segments into one large, flat network. To bridge a packet coming
from a routed interface among bridged interfaces, the bridge group should be represented by one
interface.
All ports in a BVI group must have matching maximum transmission unit (MUTT) settings.
Configure bridge groups and routed interfaces.
Enable bridging.
a.
b. Assign interfaces to the bridge groups.
c. Configure the routing.
Enable IRB.
Configure the BVI.
Enable the BVI to accept routed packets.
a.
Enable routing on the BVI.
b.
Configure IP addresses on the routed interfaces.
Verify the IRB configuration.
Purpose
Defines one or more bridge groups.
Enters interface configuration mode.
Assigns the interface to the specified bridge
group.
Returns to privileged EXEC mode.

Chapter 12 Configuring IRB