Contents

Configuring ANCP·· 1

About ANCP· 1

How ANCP works· 1

Protocols and standards· 2

ANCP tasks at a glance· 2

Enabling the ANCP server 3

Configuring the adjacency timer 3

Configuring the maximum number of retransmission attempts· 3

Creating an ANCP neighbor 4

Configuring an ANCP neighbor ID·· 4

Configuring a source interface for a neighbor 4

About the sources interface for a neighbor 4

Restrictions and guidelines for the source interface of a neighbor 5

Configuring the global source interface in system view· 5

Configuring a source interface for a neighbor in neighbor view· 5

Configuring the DSL entry aging time· 5

Configuring ANCP OAM·· 6

Assigning a service profile to a DSL· 6

Display and maintenance commands for ANCP· 6

ANCP configuration examples· 7

Example: Configuring ANCP· 7

 

 

Configuring ANCP

About ANCP

Access Node Control Protocol (ANCP) is an extension of the General Switch Management Protocol version 3 (GSMPv3). It exchanges control messages between a Broadband Remote Access Server (BRAS) and an Access Node (AN).

ANCP is a TCP-based client/server protocol. Comware only supports the ANCP server.

How ANCP works

As shown in Figure 1, the ANCP client runs on a DSLAM (an AN), and the ANCP server runs on a BRAS (an H3C device). Access loops are digital subscriber lines (DSLs).

Figure 1 ANCP network diagram

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ANCP works between the DSLAM and the BRAS as follows:

1.     The ANCP client establishes a TCP connection to the ANCP server on port 6068.

2.     The client and server establish an ANCP adjacency and complete ANCP negotiation:

a.     The client and the server send each other a SYN message.

The SYN message contains the version number, adjacency timer, sender MAC address, and the capabilities that the sender supports.

The BRAS can only use its bridge MAC as the sender MAC address. By default, the DSLAM uses its bridge MAC as the sender MAC address. Its sender MAC address is configurable.

ANCP retransmits the SYN message if it does not receive the SYN message from its peer before the proposed adjacency timer expires. If SYN retransmission attempts exceed the limit, ANCP terminates the TCP connection.

b.     The client and the server send each other a SYNACK message that contains negotiated values.

The negotiated values include the longer adjacency timer and the capabilities supported by both ends.

The capabilities supported by the ANCP server include dynamic topology discovery, DSL service profile assignment, and DSL OAM.

The two ends cannot establish an adjacency if they use different version numbers.

ANCP retransmits the SYNACK message if it does not receive the SYNACK message from its peer before the negotiated adjacency timer expires. If SYNACK retransmission attempts exceed the limit, ANCP terminates the TCP connection.

c.     The server and the client send each other an ACK message to establish an ANCP adjacency.

ANCP retransmits the ACK message if it does not receive the ACK message from its peer before the negotiated adjacency timer expires. If one end does not receive an ACK message from its peer within three intervals, it sends a RSTACK message to terminate the TCP connection.

3.     ANCP performs the following functions:

¡     ANCP adjacency maintenance

The client and the server periodically send ACK messages at the interval set by the negotiated adjacency timer. If one end does not receive an ACK message from its peer within three intervals, it sends a RSTACK message to terminate the TCP connection.

¡     Dynamic topology discovery

The client sends information about active DSLs to the BRAS. The information includes DSL status, and the actual and maximum uplink and downlink rates. When an active DSL has a state or parameter change, the client notifies the server about the change.

The server uses the DSL information to avoid congestion on the access network.

¡     Service profile assignment

The RADIUS server assigns a service profile to the ANCP server when a user accesses the network or customizes services through a DSL. The ANCP server sends the service profile to the ANCP client. The ANCP client applies the service profile to the DSL.

The ANCP server uses a DSL ID in the DHCP Option 82 or PPPoE+ message from the ANCP client to identify a DSL.

¡     DSL OAM

The ANCP server sends a message to the ANCP client for DSL OAM. The ANCP client performs loopback detection on the specified DSL and sends the result to the ANCP server.

Protocols and standards

·     RFC 3292: GSMPv3

·     RFC 6320: Protocol for Access Node Control Mechanism in Broadband Networks

ANCP tasks at a glance

To configure ANCP, perform the following tasks:

1.     Enabling the ANCP server

2.     (Optional.) Configuring the adjacency timer

3.     (Optional.) Configuring the maximum number of retransmission attempts

4.     Creating an ANCP neighbor

5.     Configuring an ANCP neighbor ID

6.     Configuring a source interface for a neighbor

7.     (Optional.) Configuring the DSL entry aging time

8.     (Optional.) Configuring ANCP OAM

9.     (Optional.) Assigning a service profile to a DSL

Enabling the ANCP server

About this task

You must enable the ANCP server. If the ANCP server is disabled, the system terminates all ANCP adjacencies and closes TCP port 6068.

Procedure

1.     Enter system view.

system-view

2.     Enable the ANCP server.

ancp enable

By default, the ANCP server is disabled.

Configuring the adjacency timer

About this task

The ANCP server and the ANCP client exchange SYN packets to negotiate adjacency timers. The two ends use the longer adjacency timer to send SYNACK and ACK packets.

Restrictions and guidelines

If you modify the adjacency timer after an ANCP adjacency is established, the change does not take effect immediately. The change takes effect after the ANCP adjacency is disconnected and adjacency timers are negotiated again.

Procedure

1.     Enter system view.

system-view

2.     Configure the adjacency timer.

ancp session interval interval

The default adjacency timer is 25 seconds.

Configuring the maximum number of retransmission attempts

About this task

The ANCP server retransmits a SYN or SYNACK message if it does not receive the message from its peer before the adjacency timer expires. If the peer does not respond after the retransmission attempts reach the maximum, the server closes the TCP connection.

Procedure

1.     Enter system view.

system-view

2.     Configure the maximum number of retransmission attempts.

ancp session retransmit retransmit-value

By default, the maximum number of retransmission attempts is 10.

Creating an ANCP neighbor

About this task

ANCP clients are the ANCP neighbors of the ANCP server. You can create multiple ANCP neighbors and configure parameters for each neighbor.

Procedure

1.     Enter system view.

system-view

2.     Create an ANCP neighbor and enter its view.

ancp neighbor neighbor-name

By default, no ANCP neighbor exists.

Configuring an ANCP neighbor ID

About this task

The ANCP server uses ANCP neighbor IDs to identify ANCP clients. If the MAC address of a client does not match any ANCP neighbor ID, the server closes the TCP connection to the client.

Restrictions and guidelines

A neighbor ID uniquely identifies an ANCP neighbor.

If you remove a neighbor ID, the server closes the TCP connection to the corresponding neighbor.

Procedure

1.     Enter system view.

system-view

2.     Enter ANCP neighbor view.

ancp neighbor neighbor-name

3.     Configure an ANCP neighbor ID.

peer-id peer-id

By default, no ANCP neighbor ID exists.

Configuring a source interface for a neighbor

About the sources interface for a neighbor

A neighbor-specific source interface must be a loopback interface. The ANCP server uses one of the following addresses as the source IP address for TCP packets sent to an ANCP neighbor:

·     The primary IPv4 address of the source interface.

·     The first IPv6 global unicast address of the source interface.

Restrictions and guidelines for the source interface of a neighbor

You must configure a global source interface or neighbor-specific source interface, or both. The ANCP server prefers the neighbor-specific source interface over the global source interface when it communicates with the neighbor.

If you delete a neighbor-specific source interface, and no global source interface exists, the device closes TCP port 6068 for the neighbor. If you change the source interface, the device uses the IP address of the new source interface. The delete or change operation does not affect existing TCP connections.

Configuring the global source interface in system view

1.     Enter system view.

system-view

2.     Configure the global source interface.

ancp source-interface loopback interface-number

By default, no global source interface exists.

Configuring a source interface for a neighbor in neighbor view

1.     Enter system view.

system-view

2.     Enter ANCP neighbor view.

ancp neighbor neighbor-name

3.     Configure a source interface for a neighbor.

source-interface loopback interface-number

By default, no source interface is configured for a neighbor.

Configuring the DSL entry aging time

About this task

The server records DSL information in DSL entries. If a user on a DSL goes offline, the server will remove the corresponding DSL entry when its aging timer expires.

Restrictions and guidelines

If an ANCP neighbor needs to reboot the DSL after receiving a service profile, the DSL entry aging time configured for the neighbor must be long enough for the neighbor to complete the reboot.

Procedure

1.     Enter system view.

system-view

2.     Enter ANCP neighbor view.

ancp neighbor neighbor-name

3.     Configure the DSL entry aging time.

aging-time value

The default aging time is 150 seconds.

Configuring ANCP OAM

About this task

You can start an OAM test for a DSL to monitor the status of the DSL. The BRAS sends a message to the DSLAM for DSL OAM. The DSLAM performs status detection on the specified DSL and sends the result to the BRAS.

Procedure

1.     Enter system view.

system-view

2.     Start an ANCP OAM test for a DSL.

ancp oam [ count test-counter | timeout time-value ] * access-loop circuit-id

Assigning a service profile to a DSL

About this task

The ANCP server can convey service profiles received from the RADIUS server to clients. You can also manually assign a service profile to a DSL from the server.

Restrictions and guidelines

The service profile must already exist on the DSLAM.

Procedure

1.     Enter system view.

system-view

2.     Assign a service profile to a DSL.

ancp access-loop-configure circuit-id circuit-id service-profile profile-name [ timeout time-value ]

Display and maintenance commands for ANCP

Execute display commands in any view and reset command in user view.

 

Task	Command
Display information about ANCP neighbors.	display ancp neighbor [ neighbor-name ]
Display information about DSL entries.	display ancp access-loop [ circuit-id circuit-id | neighbor neighbor-name ]
Display ANCP neighbor statistics.	display ancp statistics [ neighbor neighbor-name ]
Clear ANCP neighbor information and close TCP connections.	reset ancp neighbor [ neighbor-name ]
Delete DSL entries.	reset ancp access-loop [ circuit-id circuit-id | neighbor neighbor-name ]
Clear ANCP neighbor statistics.	reset ancp statistics [ neighbor neighbor-name ]

 

ANCP configuration examples

Example: Configuring ANCP

Network configuration

As shown in Figure 2, users access the network through IPoE or PPPoE. The RADIUS server performs user authentication and accounting.

Configure ANCP to achieve the following purposes:

·     The BRAS can dynamically discover DSLs on the DSLAM.

·     The BRAS can configure DSLs.

·     The BRAS can perform OAM tests on DSLs.

Figure 2 Network diagram

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Prerequisites

1.     Configure the DSLAM so it can reach interface loopback 1 on the BRAS.

2.     Enable the ANCP client on the DSLAM.

3.     Configure BRAS access, including the authentication scheme, accounting scheme, RADIUS server, address pool, uplink interfaces, and so on. For more information, see related configuration guides.

Procedure

# Enable the ANCP server on the BRAS.

<BRAS> system-view

[BRAS] ancp enable

# Create an ANCP neighbor.

[BRAS] ancp neighbor test1

# Configure an ANCP neighbor ID.

[BRAS-ancp-neighbor-test1] peer-id 1-2-3

[BRAS-ancp-neighbor-test1] quit

# Configure the source interface for the ANCP neighbor.

[BRAS] interface loopback 1

[BRAS-LoopBack1] ip address 10.10.10.10

[BRAS-LoopBack1] quit

[BRAS] ancp neighbor test1

[BRAS-ancp-neighbor-test1] source-interface loopback 1

# Configure the DSL entry aging time as 100 seconds.

[BRAS-ancp-neighbor-test1] aging-time 100

[BRAS-ancp-neighbor-test1] quit

Verifying the configuration

# Verify that the BRAS and the DSLAM have established an ANCP adjacency.

[BRAS] display ancp neighbor test1

Neighbor name               : test1

Peer ID                     : 0001-0002-0003

Source interface            : LoopBack1

Session message interval    : 25 s

Session message retransmit  : 10

Aging time                  : 100 s

State                       : used

Peer IP                     : 10.1.1.2

Peer port                   : 510

Neighbor capacities         : discovery, line-cfg, oam

Negotiated interval         : 25.0 s

Access loop number          : 3

# Verify that the BRAS has created DSL entries.

[BRAS] display ancp access-loop

Total entries: 3

Neighbor name     Peer ID           Circuit ID         State

test1             0001-0002-0003    Access1            UP

test1             0001-0002-0003    Access2            UP

test1             0001-0002-0003    Access3            UP

[BRAS] display ancp access-loop circuit-id Access1

Neighbor name                       : test1

Circuit ID                          : Access1

Remote ID                           : remote3

Peer ID                             : 0001-0002-0003

DSL type                            : ADSL1

Actual data rate upstream           : 512 Kbps

Actual data rate downstream         : 1536 Kbps

Min data rate upstream              : 32 Kbps

Min data rate downstream            : 32 Kbps

Attainable data rate upstream       : 96 Kbps

Attainable data rate downstream     : 96 Kbps

Max data rate upstream              : 64 Kbps

Max data rate downstream            : 24544 Kbps

Min low power data rate upstream    : 0 Kbps

Min low power data rate downstream  : 0 Kbps

Max delay upstream                  : 6 s

Max delay downstream                : 16 s

Actual delay upstream               : 4 s

Actual delay downstream             : 16 s

Data link                           : ETHERNET

Encapsulation 1                     : Untagged Ethernet

Encapsulation 2                     : NA

# Verify that the BRAS can successfully assign a service profile.

[BRAS] ancp access-loop-configure circuit-id Access1 service-profile profile1 timeout 10

Issuing service profile name profile1 for Access1. Please wait…

Issued the service profile name successfully.

# Verify that the BRAS can successfully start an OAM test on a DSL.

[BRAS] ancp oam count 5 timeout 5 access-loop Access1

OAM testing Access1. Please wait…

OAM test succeeded.