Configuring ANCP Neighbors

From the L2C Configuration mode (config-l2c), you can access the L2C Neighbor Configuration mode, from which you can create and manage ANCP neighbors. Tasks to configure ANCP neighbors are:

Accessing L2C Neighbor Configuration Mode for ANCP

You can create an ANCP neighbor and access the L2C Neighbor Configuration (config-l2c-neighbor) mode.

To create the ANCP neighbor and access the L2C Neighbor Configuration mode:

Issue the neighbor command in L2C Configuration mode.
host1(config-l2c)#neighbor ACCESS-NODE-1 host1(config-l2c-neighbor)#

You can use the no version to remove a specific ANCP neighbor configuration or, by omitting the neighbor name, all ANCP neighbor configurations.

Defining an ANCP Neighbor

You can define the ANCP neighbor by specifying a neighbor ID in the L2C Neighbor Configuration (config-l2c-neighbor) mode and define the maximum number of branches for the neighbor.

To specify an ANCP neighbor ID and the maximum number of branches that the neighbor can have:

From L2C Configuration mode, create an ANCP neighbor and specify the ANCP neighbor ID.
host1(config-l2c)#neighbor host1(config-l2c-neighbor)#id 1234.5678.9123
From L2C Neighbor Configuration mode, specify the maximum number of branches.
host1(config-l2c-neighbor)#max-branches 50

Storing Topology Discovery Table Data in Mirrored Storage

You can enable storage of topology discovery table data in mirrored storage by using the persist-discovery-data enable command. By default, the storage of topology discovery table data in mirrored storage is enabled.

The topology discovery table is used to store digital subscriber line (DSL) parameters in the router. Based on the DSL parameters, quality-of-service (QoS) shaping for each subscriber is determined. When two devices such as the Broadband Remote Access Server (B-RAS) and digital subscriber line access multiplexer (DSLAM) are synchronized on the basis of the agreed capabilities, the DSLAM sends port-related information about the DSL in a topology discovery table message to the B-RAS.

The DSLAM sends topology discovery table data to the B-RAS in the following scenarios:

When the layer 2 control (L2C) session is up
When the line parameter changes are sensed or reported in the B-RAS by the DSLAM
When the DSL is down

JunosE Software inserts topology discovery table data from the DSLAM into mirrored storage so that the data continues to be available even after SRP switchover. Therefore the subscriber is able to use the existing port data until the Access Node Control Protocol (ANCP) session is re-established and the DSLAM sends the updated data. When the updated port data is received from the DSLAM, corresponding entries are modified in the mirrored storage.

To enable storage of topology discovery table data in mirrored storage:

Issue the persist-discovery-data enable command in L2C Configuration mode.

host1(config-l2c)#persist-discovery-data enable

Use the no version to disable storage of topology discovery table data in mirrored storage and completely clear existing data in mirrored storage.

Limiting Topology Discovery Table Entries

You can specify the maximum number of discovery table entries that a neighbor can have.

To specify the maximum number of entries:

Issue the max-discovery-table-entries command in L2C Neighbor Configuration mode.
host1(l2c-neighbor)#max-discovery-table-entries 4000

You can use the no version to return the maximum number of discovery table entries to its default value, 10,000 entries.

Note: Using this command to change the maximum number of entries when an already greater number of current entries exists in the discovery table does not remove any existing entries. Instead, future entries are prevented. For example, if the current table contains 5000 entries, and you specify a maximum of 4000 entries, the software does not remove any existing entries from the table. The software prevents any new entries until the number of table entries falls below the specified maximum.

Clearing ANCP Neighbors

You can clear an existing ANCP neighbor and reset the specified GSMP neighbor session. Issuing the clear l2c neighbor command removes all QoS parameter instances associated with the neighbor, including those associated with the QoS downstream rate and QoS cell mode applications.

To clear an existing ANCP neighbor:

Issue the clear l2c neighbor command in Privileged Exec mode.
host1#clear l2c neighbor ACCESS_NODE_1

There is no no version.