Concurrent Routing And Bridging - Juniper JUNOSE 11.1.X - LINK LAYER CONFIGURATION 4-7-2010 Configuration Manual

Table 26: Default Subscriber Policies for Bridge Group Interfaces (continued)
You cannot change the default subscriber policy values listed in Table 26 on page 470
for a trunk bridge interface. You can, however, configure a nondefault subscriber
policy for a subscriber bridge interface to change the default permit or deny value
for one or more packet or attribute types. For details, see "Configuring Subscriber
Policies" on page 480.

Concurrent Routing and Bridging

After you create the necessary bridge groups and bridge interfaces for your network
configuration, you can use the bridge crb command to enable concurrent routing
and bridging (CRB) for all bridge groups configured on your router. When CRB is
enabled, the router can route a protocol among a group of interfaces in one bridge
group and concurrently bridge the same protocol among a separate group of interfaces
in a different bridge group on the router.
The router does not switch the protocol between the two bridge groups. Instead, it
confines routed traffic to the routed interfaces and bridged traffic to the bridged
interfaces. As a result, a protocol can be either routed or bridged on a particular
interface, but cannot be both routed and bridged on the same interface.
By default, CRB is disabled for all bridge groups on the router. When you use the
bridge crb command to enable CRB, it takes effect for all bridge groups currently
configured on your router; you cannot enable CRB for some bridge groups on the
router but not for others.
When you first enable CRB, the router issues an implicit bridge route command for
any IP, MPLS, or PPPoE interfaces that are currently configured in the interface stack
for the bridge group. This command directs the bridge group to route traffic for these
protocols. After CRB has been enabled, you must issue an explicit bridge route
command to route any new IP, MPLS, or PPPoE interface that is the first occurrence
of this protocol in the bridge group. (See "Configuring Explicit Routing" on page 486
for details about using the bridge route command.)
As a result, it is important that you issue the bridge crb command after you configure
all bridge group interfaces. In this way, the router can detect all IP, MPLS, or PPPoE
interfaces in your configuration and direct the bridge group to route traffic from these
protocols.
Packet/Attribute Type Default Subscriber Policy
PPPoE Permit
Relearn Permit
Unicast (user-to-user) Permit
Unknown unicast DA Deny
Unknown protocol Permit
Chapter 15: Configuring Transparent Bridging
Default Trunk Policy
Permit
Permit
Permit
Permit
Permit
Overview
471