Configuring Transparent Bridging
Transparent and SRT Bridging Configuration Task List
BC-34
Cisco IOS Bridging and IBM Networking Configuration Guide
Configuring a Subscriber Bridge Group
The Digital Subscriber Line (xDSL) bridge support feature enables you to configure a router for
intelligent bridge flooding for xDSL and other bridge applications. To configure a subscriber bridge
group, use the following commands, beginning in global configuration mode:
Note Standard access lists can coexist with the subscriber policy. However, subscriber policy
will take precedence over the access list by being checked first. A packet permitted by the
subscriber policy will be checked against the access list if it is specified. A packet denied
by subscriber policy will be dropped with no further access list checking.
Configuring Transparent Bridging over WANs
You can configure transparent bridging over a variety of networks, as described in the following sections:
•Configuring Fast-Switched Transparent Bridging over ATM, page 34
•Configuring Transparent Bridging over DDR, page35
•Configuring Transparent Bridging over Frame Relay, page 36
•Configuring Transparent Bridging over Multiprotocol LAPB, page37
•Configuring Transparent Bridging over SMDS, page38
•Configuring Transparent Bridging over X.25, page38

Configuring Fast-Switched Transparent Bridging over ATM

Our bridging implementation supports IEEE 802.3 frame formats and IEEE 802.10 frame formats. Our
implementation can transparently bridge ARPA style Ethernet packets (also known as Ethernet version
2).
Fast-switched transparent bridging over Asynchronous Transfer Mode (ATM) supports AAL5-SNAP
encapsulated packets only. All bridged AAL5-SNAP encapsulated packets are fast switched.
Fast-switched transparent bridging supports Ethernet, FDDI, and Token Ring packets sent in
AAL5-SNAP encapsulation over ATM. See the section “Fast-Switched Transparent Bridging over ATM
Example (Cisco 7000)” for an example configuration of fast-switched transparent bridging over ATM.
Command Purpose
Step1 bridge bridge-group protocol {ieee |
dec | vlan-bridge}
Defines the bridge Spanning-Tree Protocol.
Step2 bridge bridge-group subscriber-policy
policy Defines a subscriber bridge group and specifies the subscriber policy
for the group.
Step3 subscriber-policy policy [[no]
[default] packet [permit] [deny]]
Defines or modifies the forward and filter decisions of the subscriber
policy.
Step4 interface type number Configures a subinterface.
Step5 bridge-group bridge-group
[subscriber-trunk]
Assigns a subscriber bridge group and indicates whether the
interface is upstream or downstream from the traffic flow.