BCP Support
The Bridge Control Protocol (BCP) Support feature provides support for BCP to Cisco devices, as described in RFC 3518. The Cisco implementation of BCP is a VLAN infrastructure that does not require the use of subinterfaces to group Ethernet 802.1Q trunks and the corresponding PPP links. This approach enables users to process VLAN encapsulated packets without having to configure subinterfaces for every possible VLAN configuration.
Feature History for the BCP Support feature
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12.3(2)T |
This feature was introduced. |
12.3(4)T |
This feature was modified to enhance the performance of the bridging of Ethernet packets over PPP-encapsulated interfaces. The ppp bcp tagged-frame command was introduced to provide the option to either enable or disable the negotiation of IEEE 802.1Q-tagged packets. |
Finding Support Information for Platforms and Cisco IOS Software Images
Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at http://www.cisco.com/go/fn. You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions that appear.
Contents
•Restrictions for BCP Support
•Information About BCP Support
•How to Bridge a Range of VLAN IDs
•Configuration Examples for BCP Support
•Additional References
•Command Reference
Restrictions for BCP Support
Each individual VLAN ID can be configured only once, as either part of a single VLAN ID range or on a subinterface.
Information About BCP Support
To configure the BCP Support feature, you must understand the following concept:
•VLAN ID Ranges
VLAN ID Ranges
In the traditional, subinterface-based approach to VLANs, a subinterface is created for every necessary VLAN ID, and then the application or protocol attributes are configured on every subinterface. In the VLAN range approach, a single VLAN ID range is created, and the application or protocol attributes are configured on the range as a whole.
How to Bridge a Range of VLAN IDs
This section contains the following procedures:
•Configuring a Range of VLAN IDs
•Enabling the Negotiation of IEEE 802.1Q-Tagged Packets
Configuring a Range of VLAN IDs
In this task, you create a range of VLAN IDs and then assign the VLAN ID range to the serial interface.
SUMMARY STEPS
1. enable
2. configure terminal
3. no ip routing
4. bridge number protocol ieee
5. interface type number
6. vlan-range dot1q start-range end-range [native]
7. description description
8. bridge-group number
9. exit
10. interface type number
11. encapsulation ppp
12. bridge-group number
DETAILED STEPS
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Step 1 |
enable
Router(config)# enable |
Enters privileged EXEC mode. •Enter your password if prompted. |
Step 2 |
configure terminal Router(config)# configure terminal |
Enters global configuration mode. |
Step 3 |
no ip routing
Router(config)# no ip routing |
Disables all routing. |
Step 4 |
bridge number protocol ieee
Router(config)# bridge 1 protocol ieee |
Enables bridge and spanning-tree protocols. |
Step 5 |
interface type number
Router(config)# interface ethernet 0 |
Enters interface configuration mode. •This is the Ethernet interface that is connected to the 802.1Q trunk. Both the Ethernet interface and the serial interface must be assigned to the same bridge group. |
Step 6 |
vlan-range dot1q start-range end-range [native]
Router(config-if)# vlan-range dot1q 1 99 |
Configures the range of VLAN IDs the interface is to bridge and enters VLAN range configuration mode. •Configuring the native keyword instructs the interface to bridge untagged (native) packets. |
Step 7 |
description description
Router(config-if-vlan-range)# description 1 to 99 |
(Optional) Describes the VLAN ID range. |
Step 8 |
bridge-group number
Router(config-if-vlan-range)# bridge-group 1 |
Assigns the VLAN ID range to a bridge group. |
Step 9 |
exit
Router(config-if-vlan-range)# exit |
Exits to global configuration mode. |
Step 10 |
interface type number
Router(config)# interface serial 1 |
Enters interface configuration mode. |
Step 11 |
encapsulation ppp
Router(config-if)# encapsulation ppp |
Enables PPP on the interface. |
Step 12 |
bridge-group number
Router(config-if)# bridge-group 1 |
Assigns the interface to a bridge group. •The serial interface must be assigned to the same bridge group as the Ethernet interface that is connected to the 802.1Q trunk. |
Enabling the Negotiation of IEEE 802.1Q-Tagged Packets
In this task, you enable the negotiation of IEEE 802.1Q-tagged packets.
SUMMARY STEPS
1. enable
2. configure terminal
3. interface type number
4. ppp bcp tagged-frame
DETAILED STEPS
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Step 1 |
enable
Router(config)# enable |
Enters privileged EXEC mode. •Enter your password if prompted. |
Step 2 |
configure terminal
Router(config)# configure terminal |
Enters global configuration mode. |
Step 3 |
interface type number
Router(config)# interface serial 4/0 |
Enters interface configuration mode. •This is the interface that will be bridging the IEEE 802.1Q-tagged packets. |
Step 4 |
ppp bcp tagged-frame
Router(config-if)# ppp bcp tagged-frame |
Enables the negotiation of IEEE 802.1Q-tagged packets. |
Configuration Examples for BCP Support
This section provides the following configuration examples:
•Bridging a Range of VLAN IDs: Example
•Bridging a Range of VLAN IDs over Multiple Interfaces: Example
•Bridging a Range of VLAN IDs from Untagged Packets: Example
•Enabling the Negotiation of IEEE 802.1Q-Tagged Packets: Example
Bridging a Range of VLAN IDs: Example
The following example bridges tagged 802.1Q packets that have VLAN IDs from 1 to 500. Ingress packets that have VLAN IDs outside of this range are dropped.
Bridging a Range of VLAN IDs over Multiple Interfaces: Example
The following example bridges two ranges of VLAN IDs. Packets with a VLAN ID from 1 to 600 are bridged by serial interface 0, and packets with a VLAN ID from 800 to 4000 are bridged by serial interface 1.
vlan-range dot1q 800 4000
Bridging a Range of VLAN IDs from Untagged Packets: Example
The following example bridges untagged packets with a VLAN ID from 1 to 500:
vlan-range dot1q 1 500 native
Enabling the Negotiation of IEEE 802.1Q-Tagged Packets: Example
The following example enables the negotiation of IEEE 802.1Q-tagged packets on serial interface 4/0:
Additional References
The following sections provide references related to BCP support:
RFCs
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3518 |
Point-to-Point Protocol (PPP) Bridging Control Protocol (BCP) |
2878 |
Point-to-Point Protocol (PPP) Bridging Control Protocol (BCP) |
1638 |
PPP Bridging Control Protocol (BCP) |
Technical Assistance
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Technical Assistance Center (TAC) home page, containing 30,000 pages of searchable technical content, including links to products, technologies, solutions, technical tips, and tools. Registered Cisco.com users can log in from this page to access even more content. |
http://www.cisco.com/public/support/tac/home.shtml |
Command Reference
The following commands are introduced or modified in the feature or features documented in this module. For information about these commands, see the Cisco IOS Bridging Command Reference at http://www.cisco.com/en/US/docs/ios/bridging/command/reference/br_book.html or the Cisco IOS IBM Networking Command Reference at http://www.cisco.com/en/US/docs/ios/ibm/command/reference/ibm_book.html. For information about all Cisco IOS commands, go to the Command Lookup Tool at http://tools.cisco.com/Support/CLILookup or to the Cisco IOS Master Commands List.
New Commands
•debug tbridge virtual-port
•ppp bcp tagged-frame
•vlan-id dot1q
•vlan-range dot1q
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