Table Of Contents
Prerequisites for Access Node Control Protocol
Restrictions for Access Node Control Protocol
Information About Access Node Control Protocol
Noninteractive Operation, Administration, and Maintenance
General Switch Management Protocol and ANCP
How to Configure Access Node Control Protocol
Enabling ANCP on an Ethernet Interface
Enabling ANCP on an ATM Interface
Mapping DSLAM Ports to VLAN Interfaces on Broadband Remote Access Servers
Mapping DSLAM Ports to PVC Interfaces on Broadband Remote Access Servers
Configuration Examples for Access Node Control Protocol
Enabling Access Node Control Protocol on Ethernet Interfaces: Example
Enabling Access Node Control Protocol on ATM Interfaces: Example
Mapping DSLAM Ports to VLAN Interfaces on the BRAS: Example
Mapping DSLAM Ports to PVC Interfaces on the BRAS: Example
Feature Information for Access Node Control Protocol
Access Node Control Protocol
First Published: June 25, 2009Last Updated: June 25, 2009The Access Node Control Protocol (ANCP) feature enhances communication between Digital Subscriber Line Access Multiplexers (DSLAMs) and a broadband remote access server (BRAS), enabling the exchange of events, actions, and information requests between the multiplexer end and the server end. As a result, either end can implement appropriate actions.
Finding Feature Information
For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the "Feature Information for Access Node Control Protocol" section.
Use Cisco Feature Navigator to find information about platform support and Cisco IOS XE software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Contents
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Prerequisites for Access Node Control Protocol
•
Restrictions for Access Node Control Protocol
•
Information About Access Node Control Protocol
•
How to Configure Access Node Control Protocol
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Configuration Examples for Access Node Control Protocol
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Feature Information for Access Node Control Protocol
Prerequisites for Access Node Control Protocol
To run ANCP over Transmission Control Protocol (TCP), IP must be enabled on broadband remote access servers (BRAS). Interactions from RADIUS to the BRAS are not required for ANCP and are dependent on the RADIUS server.
For information about release and platform support, see the "Feature Information for Access Node Control Protocol" section.
Restrictions for Access Node Control Protocol
Cisco IOS XE Release 2.4 supports interactions with the RADIUS server from the broadband remote access server (BRAS). Interactions from RADIUS to the BRAS are not required for ANCP and are dependent on the RADIUS server.
Information About Access Node Control Protocol
ANCP is used to aggregate traffic from multiple subscribers and deliver information for any application, while remaining independent from the application. ANCP is currently used in the application between DSLAMs and the broadband remote access server in a digital subscriber line (DSL) broadband environment.
The ANCP feature enables close communication between DSL aggregation multiplexers (DSLAMs) and network edge devices. Using ANCP between DSLAMs and a BRAS enables exchange of events, actions, and information requests so that the appropriate actions occur at the DSLAM and BRAS.
The ANCP architecture supports the following uses of ANCP:
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Noninteractive Operation, Administration, and Maintenance
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General Switch Management Protocol and ANCP
Rate Adaptive Mode
Rate adaptive mode helps to maximize the line bit rate for a given line, and the rate is dependent on the quality of the signal achieved on the line. Rate adaptive mode conveys DSL modem line rate from a DSLAM to a broadband remote access server.
A BRAS running ANCP listens for TCP requests from its ANCP neighbors (DSLAMs).
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After a TCP session is established—ANCP begins exchanging messages to establish adjacency between the BRAS and its neighbors.
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After adjacency is established—ANCP event messages can be sent from the DSLAM to the BRAS.
Rate adaptive DSL uses signal quality to adjust line speeds. A BRAS typically sets the subscriber interfaces to the maximum bandwidth agreed to in the service license agreement (SLA).
When customer premises equipment (CPE) is synchronized to a data rate that is lower than the line speed, cell or packet loss occurs on the DSLAM. To prevent this, the DSLAM can use ANCP to notify the BRAS of newly adjusted circuit rates.
When a customer-facing port:
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Activates — The DSLAM sends a Port Up message to the BRAS. The appropriate quality of service (QoS) takes effect in accordance with the ANCP-delivered information.
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Deactivates — The DSLAM sends a Port Down message to the BRAS. ANCP reports the DSL state sent by the DSLAM, which is typically Silent or Idle. If the broadband remote access server receives another Port Up message, the subscriber sessions either time out or are renewed with a new shaping rate. The shaping rate on the interface does not change until the router receives a new Port Up message.
RADIUS Interaction
Interactions between the broadband remote access server and the RADIUS server are from the router to RADIUS.
The BRAS sends the following attributes and attribute-value pairs (AVPs) to the RADIUS server:
The BRAS uses Point-to-Point Protocol (PPPoE) to interact with the authentication, authorization, and accounting (AAA) module. RADIUS processes the information and then takes appropriate action.
Port Mapping
Port mapping associates customer premises equipment (CPE) clients of a DSLAM with VLAN subinterfaces on the BRAS. The VLANs include 802.1Q or queue-in-queue (Q-in-Q) hierarchical VLANs. Port mapping is configured in global configuration mode on the BRAS by grouping CPE client IDs with a specific DSLAM neighbor.
There are two methods you can use to map ports: configure all VLAN subinterfaces first, and the ANCP neighbor mappings next. Or, you can configure the mappings directly under the interface.
For example, the following commands configure port mapping for Q-in-Q VLAN subinterfaces:
ancp neighbor name dslam-name id dslam-iddot1q outer-vlanid second-dot1q inner-vlanid [interface type number] client-id "client-id"or
ancp neighbor name dslam-name id dslam-iddot1q outer-vlanid client-id "client-id"The client-id is a unique access-loop-circuit-id that the DSLAM sends to the BRAS for each unique port. The DSLAM sends this ID in the ANCP Port Up event message. The access-loop-circuit-id uses a defined format consisting of an access node identifier and digital subscriber line (DSL) information as mentioned below:
ATM/DSL
"access-node-identifier atm slot/module/port.subinterface:vpi.vci"
Ethernet/DSL
"access-node-identifier ethernet slot/module/port.subinterface[:vlan-id]"
The BRAS sets the default state as Down, on all ports of the router, until the DSLAM sends a Port Up message.
Noninteractive Operation, Administration, and Maintenance
ANCP provides an out-of-band control channel for performing noninteractive operation, administration, and maintenance (OAM) operations from the broadband remote access server. This channel enables router operators to view the ANCP port state of specific DSLAM ports. ANCP port state information is stored in the ANCP dynamic database on the BRAS.
Interactive OAM
The Interactive OAM and Scaling Improvements feature adds on-demand ping capability to ANCP for operations and troubleshooting.
Note
This feature is enabled by default and requires no configuration.
General Switch Management Protocol and ANCP
ANCP is an extension of the General Switch Management Protocol (GSMP). GSMP defines a master-slave neighbor relationship in which the master initiates a connection to a slave. In ANCP, this master-slave relationship is reversed—the BRAS (master) listens and accepts incoming ANCP connections from the DSLAM (slave). The DSLAM uses event messages to communicate asynchronous events to the BRAS, such as topology changes and Port Down or Port Up events.
GSMP connectivity between the BRAS and the DSLAM occurs over TCP/IP (RFC 3293). The DSLAM initiates the connection to the router and the router accepts the connection if the appropriate interface is ANCP enabled.
The GSMP Adjacency Protocol establishes GSMP neighbor relationships.
1.
During the adjacency-building:
a.
The DSLAM and router negotiate their capabilities and determine the synchronization state between the two ends.
b.
GSMP detects whether the router and the DSLAM have retained a local information database state in case of a transport failure, or whether both devices require a state update.
c.
If GSMP determines that it must resynchronize the adjacency, it restarts the adjacency synchronization process, which includes the capability negotiation defined in the ANCP extension draft available at:
http://tools.ietf.org/id/draft-wadhwa-gsmp-l2control-configuration-02.txt
2.
In an ANCP, if a neighbor (neighbor1) contains capabilities that its neighbor (neighbor2) does not support, neighbor1 turns off the capabilities and recommunicates the packets to neighbor2 with the same set of capabilities as neighbor2.
3.
After both the neighbors agree to the same set of capabilities, adjacency is established.
How to Configure Access Node Control Protocol
To configure ANCP, perform the following global or interface configuration tasks:
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Enabling ANCP on an Ethernet Interface
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Enabling ANCP on an ATM Interface
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Mapping DSLAM Ports to VLAN Interfaces on Broadband Remote Access Servers
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Mapping DSLAM Ports to PVC Interfaces on Broadband Remote Access Servers
Enabling ANCP on an Ethernet Interface
Use the following procedure to enable ANCP on an Ethernet interface.
SUMMARY STEPS
1.
enable
2.
configure terminal
3.
ancp adjacency timer interval
4.
interface type number
5.
ip address address mask
6.
ancp enable
7.
interface type number.subinterface
8.
encapsulation dot1q vlanid [second-dot1q second-vlanid]
9.
exit
DETAILED STEPS
Enabling ANCP on an ATM Interface
The ancp enable command should be configured only for the control VCs on which the ANCP message is sent from the DSLAM. Use the following procedure to enable ANCP on ATM interfaces.
SUMMARY STEPS
1.
enable
2.
configure terminal
3.
ancp adjacency timer interval
4.
interface atm slot/subslot/port.subinterface
5.
ip address ip-address mask
6.
pvc vpi/vci
7.
ancp enable
8.
exit
DETAILED STEPS
Mapping DSLAM Ports to VLAN Interfaces on Broadband Remote Access Servers
Use the following procedure to map DSLAM ports to VLAN interfaces on the BRAS.
SUMMARY STEPS
1.
enable
2.
configure terminal
3.
ancp atm shaper percent-factor factor
4.
interface type number.subinterface
5.
encapsulation dot1q vlan-id
6.
ancp neighbor name dslam-name [id dslam-id] client-id client-id
7.
exit
DETAILED STEPSMapping DSLAM Ports to PVC Interfaces on Broadband Remote Access Servers
The ancp neighbor name command is available under pvc and pvc-in-range command modes. This command creates a one-to-one mapping between a PVC and a DSLAM port. Use the following procedure to map DSLAM ports to PVC interfaces on the BRAS.
SUMMARY STEPS
1.
enable
2.
configure terminal
3.
ancp atm shaper percent-factor factor
4.
interface atm slot/subslot/port.subinterface
5.
pvc vpi/vci
or
range pvc start-vpi/start-vci end-vpi/end-vci6.
pvc-in-range vpi/vci
7.
ancp neighbor name dslam-name [id dslam-id] client-id client-id
8.
end
DETAILED STEPSConfiguration Examples for Access Node Control Protocol
This section provides the following configuration examples:
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Enabling Access Node Control Protocol on Ethernet Interfaces: Example
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Enabling Access Node Control Protocol on ATM Interfaces: Example
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Mapping DSLAM Ports to VLAN Interfaces on the BRAS: Example
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Mapping DSLAM Ports to PVC Interfaces on the BRAS: Example
Enabling Access Node Control Protocol on Ethernet Interfaces: Example
The following example shows how to enable ANCP on Ethernet subinterface 2/0/1.
interface GigabitEthernet 2/0/1ip address 192.168.64.16 255.255.255.0ancp enable!interface GigabitEthernet 2/0/1.1encapsulation dot1q 100 second-dot1q 200!ancp adjacency timer 100Enabling Access Node Control Protocol on ATM Interfaces: Example
The following example shows how to enable ANCP on ATM subinterface 2/0/1.1.
interface ATM2/0/0.1 point-to-pointdescription ANCP Link to one DSLAMno ip mroute-cacheip address 192.168.0.2 255.255.255.252pvc 254/32protocol ip 192.168.0.1ancp enableno snmp trap link-statusMapping DSLAM Ports to VLAN Interfaces on the BRAS: Example
The following example shows how to map the CPE client ports of a DSLAM to Q-in-Q VLAN subinterfaces on the BRAS. In the example, the DSLAM neighbor named dslam1 with an IP address of 192.68.10.5 has a CPE client port mapped to Q-in-Q VLANs 100 and 200 configured on Ethernet interface 1/0/0.2. Another CPE client port is mapped to Q-in-Q VLANs 100 and 100 configured on Ethernet interface 1/0/0.1.
interface GigabitEthernet1/0/0.1encapsulation dot1q 100 second-dot1q 100ancp neighbor name dslam1 id 192.168.10.5 client-id "192.168.10.5 ethernet1/0/0.2"!interface GigabitEthernet1/0/0.2encapsulation dot1q 100 second-dot1q 200ancp neighbor name dslam1 id 192.168.10.5 client-id "192.168.10.5 ethernet1/0/0.1"!ancp atm shaper percent-factor 95!The example shown above maps the ports directly at the subinterface level. You can also configure all VLAN subinterfaces first, and perform the mappings under ANCP neighbor next, as shown in the following example:
interface GigabitEthernet1/0/0.1encapsulation dot1q 100 second-dot1q 100!interface GigabitEthernet1/0/0.2encapsulation dot1q 100 second-dot1q 200!ancp atm shaper percent-factor 95!ancp neighbor name dslam1 id 192.168.10.5dot1q 100 second-dot1q 100 interface GigabitEthernet1/0/0.1 client-id "192.168.10.5 ethernet1/0/0.2"!ancp neighbor name dslam1 id 192.168.10.5dot1q 100 second-dot1q 200 interface GigabitEthernet1/0/0.2 client-id "192.168.10.5 ethernet1/0/0.2"Mapping DSLAM Ports to PVC Interfaces on the BRAS: Example
The ancp neighbor name command maps the CPE client ports of a DSLAM to PVC interfaces on the BRAS. This command can be configured either globally or under PVC/PVC-in-Range mode.
In PVC or PVC-in-Range Configuration Mode
In this example, the router interfaces with one DSLAM which has two ports or clients.
interface ATM2/0/0.1 point-to-pointdescription ANCP Link to one DSLAMno ip mroute-cacheip address 192.168.0.2 255.255.255.252pvc 254/32protocol ip 192.168.0.1 255.255.255.252ancp neighbor name dslam1 id 192.168.10.5 client-id "dslam-port-x-identifier"no snmp trap link-status!interface ATM1/0/0.1 multipointdescription TDSL clients - default TDSL 1024class-int speed:ubr:1184:160:10range pvc 10/41 10/160service-policy input SET-PRECEDENCE-0service-policy output premium-plus:l2c:25088pvc-in-range 10/103description TDSL client 16 Mbps with ANCPclass-vc speed:ubr:17696:1184:05ancp neighbor name dslam1 id 192.168.10.5 client-id "dslam-port-x-identifier"!range pvc 11/41 11/160service-policy input SET-PRECEDENCE-0service-policy output premium-plus:l2c:25088pvc-in-range 11/108description TDSL client 16 Mbps with ANCPclass-vc speed:ubr:17696:1184:05ancp neighbor name dslam1 id 192.168.10.5 client-id "dslam-port-y-identifier"!In Global Configuration Mode
When the ancp neighbor command is configured globally, the PVC information for the ATM interface must also be specified, as shown in the following example:
interface ATM1/0/0.1 multipointdescription TDSL clients - default TDSL 1024class-int speed:ubr:1184:160:10range pvc 10/41 10/160service-policy input SET-PRECEDENCE-0service-policy output premium-plus:l2c:25088pvc-in-range 10/103description TDSL client 16 Mbps with ANCPclass-vc speed:ubr:17696:1184:05!range pvc 11/41 11/160service-policy input SET-PRECEDENCE-0service-policy output premium-plus:l2c:25088pvc-in-range 11/108description TDSL client 16 Mbps with ANCPclass-vc speed:ubr:17696:1184:05!ancp neighbor name dslam1 id 192.168.10.5atm 10/103 interface ATM1/0/0.1 client-id "dslam-port-x-identifier"atm 11/108 interface ATM1/0/0.1 client-id "dslam-port-y-identifier"Additional References
The following sections provide references related to the Access Node Control Protocol feature.
Related Documents
Related Topic Document TitleIEEE 802.1Q VLAN
Configuring Routing Between VLANs with IEEE 802.1Q Encapsulation
Queue-in-Queue VLAN Tags
ANCP Commands
RFCs
RFC TitleANCP extension draft
GSMP Extensions for Access Node Control Mechanism, Internet draft
RFC 3292
General Switch Management Protocol (GSMP) V3
RFC 3293
General Switch Management Protocol (GSMP), Packet Encapsulations for Asynchronous Transfer Mode (ATM), Ethernet and Transmission Control Protocol (TCP)
Technical Assistance
Feature Information for Access Node Control Protocol
Table 1 lists the features in this module and provides links to specific configuration information.
Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which Cisco IOS XE software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Note
Table 1 lists only the Cisco IOS XE software release that introduced support for a given feature in a given Cisco IOS XE software release train. Unless noted otherwise, subsequent releases of that Cisco IOS XE software release train also support that feature.
Table 1 Feature Information for Access Node Control Protocol
Feature Name Releases Feature InformationAccess Node Control Protocol
Cisco IOS XE Release 2.4
In Cisco IOS XE Release 2.4, this feature was introduced on the Cisco ASR 1000.
The following sections provide information about this feature:
•
Information About Access Node Control Protocol
•
How to Configure Access Node Control Protocol
The following command was introduced: ancp vdsl ethernet shaper.
Interactive OAM and Scaling Improvements
Cisco IOS XE Release 2.4
The Interactive OAM and Scaling Improvements feature adds on demand ping capability to ANCP for operations and troubleshooting.
In Cisco IOS XE Release 2.4, this feature was introduced on the Cisco ASR 1000.
The following commands were introduced or modified: ping ancp, show ancp neighbor port, show ancp port, show ancp session, show ancp session adjacency, show ancp session event, and show ancp statistics.
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Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.
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