ATM Attachment Circuit: VC Signaling and Provisioning

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Updated:August 2, 2010

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ATM Attachment Circuit—VC Signaling and Provisioning

Table Of Contents

ATM Attachment Circuit—VC Signaling and Provisioning

Finding Feature Information

Contents

Prerequisites for ATM Attachment Circuit—VC Signaling and Provisioning

Restrictions for ATM Attachment Circuit—VC Signaling and Provisioning

Information About ATM Attachment Circuit—VC Signaling and Provisioning

How to Configure ATM Attachment Circuit—VC Signaling and Provisioning

Configuring ATM Attachment Circuit—VC Signaling and Provisioning

Configuration Examples for ATM Attachment Circuit—VC Signaling and Provisioning

Example: Configuring ATM Attachment Circuit—VC Signaling and Provisioning Feature

Example: Verifying the VP States

Example: Verifying the VC States

Additional References

Related Documents

Standards

MIBs

RFCs

Technical Assistance

Feature Information for ATM Attachment Circuit—VC Signaling and Provisioning

ATM Attachment Circuit—VC Signaling and Provisioning

First Published: July 23, 2010

Last Updated: July 30, 2010

Bidirectional Forwarding Detection (BFD) is a generic protocol that detects faults in the bidirectional path between two forwarding engines. Virtual Circuit Connectivity Verification (VCCV), as applied to a pseudowire (PW), is a protocol that addresses the end-to-end fault detection and diagnostics for a pseudowire, for health monitoring purposes.

In the event of a fault in the local attachment circuit (AC), the ATM asynchronous feature supports keeping the virtual circuits (VC) or path provisioned on the data plane. The data plane remains continuously active so that the BFD VCCV packets are passed on to the peer within the Multiprotocol Label Switching (MPLS) core. When the interface goes down, the PVC is disabled in the line card; when the interface is up or enabled, the PVC is enabled once again.

Finding Feature Information

Your software release may not support all the features documented in this module. 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 ATM Attachment Circuit—VC Signaling and Provisioning" section.

Use Cisco Feature Navigator to find information about platform support and Cisco 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

•Prerequisites for ATM Attachment Circuit—VC Signaling and Provisioning

•Restrictions for ATM Attachment Circuit—VC Signaling and Provisioning

•Information About ATM Attachment Circuit—VC Signaling and Provisioning

•How to Configure ATM Attachment Circuit—VC Signaling and Provisioning

•Configuration Examples for ATM Attachment Circuit—VC Signaling and Provisioning

•Additional References

•Feature Information for ATM Attachment Circuit—VC Signaling and Provisioning

Prerequisites for ATM Attachment Circuit—VC Signaling and Provisioning

You need to configure the atm asynchronous command under the main ATM interface.

Cisco IOS Release 12.2(33)SRE and later support the ATM Attachment Circuit—VC Signaling and Provisioning feature only on Cisco 7600 series routers and the SIP-400 line card with Warlord Shared Port Adapter (SPA)(SPA-2XOC3-ATM) and Circuit Emulation over Packet (CEoP) SPAs and Black Russian SPAs (SPA-1CHOC3-CE-ATM).

Restrictions for ATM Attachment Circuit—VC Signaling and Provisioning

•Local switching is not supported.

•PW redundancy is not supported.

•A maximum of 2000 VCs are supported with or without OAM emulation.

•Configuring the ATM asynchronous feature is only allowed under the main interface and not supported under the subinterface. The ATM interface with the ATM Asynchronous feature supports only L2transport virtual path (VP) and L2transport VC. All the other features such as bridging, VC bundle, and IP are not supported.

•Any change to the ATM VC parameters results in the disconnection of the PW.

•Enabling or disabling the ATM Asynchronous feature on a VC causes malfunction of ATM and BFD VCCV. Once the ATM Asynchronous feature is enabled, changing the interface configuration is not recommended.

•Service Policy installation on ATM VP or L2transport VP is not supported.

Information About ATM Attachment Circuit—VC Signaling and Provisioning

When an ATM interface is shut down (Customer Edge or Provider Edge, or the ATM link is down), all the VCs and VPs configured on the interface are removed from the driver. As a result, all types of traffic including VCCV and data traffic are blocked.

When there is a fault in the access side of the ATM network, or if the ATM link facing the Customer Edge router is down on the Provider Edge (PE) router, the ATM Attachment Circuit—VC Signaling and Provisioning feature ensures that the data plane is active on the Provider Edge (PE) routers that the BFD VCCV control packets are passed on to the Route Processor from the line card for BFD VCCV processing. The ATM VCs and VPs remain provisioned in the forwarding table entries on the Network Processor and line card. As a result, when the access side network is down, the health of the MPLS core can still be monitored and there is less programming required when the fault is removed from the access side network. Additionally, the Route Processor bundles a number of requests and sends a single message to the line cards for performing different operations on the VP or VCs that contribute to better performance under scale situations.

In addition, for the ATM Attachment Circuit—VC Signaling and Provisioning feature, the following criteria apply:

•AAL5 and AAL0 encapsulation with cell packing is supported.

•The Packet Switched Network is based on a transport technology such as MPLS or Layer 2 Tunnel Protocol Version 3 (L2TPv3).

•BFD provides a generalized Hello protocol for fast failure detection of network resources such as when the interface is in a shut down state and link failures.

•VCCV provides a control channel and manages the ingress and egress points so that connectivity verification messages can be sent.

•BFD VCCV control channel mechanisms exchange connectivity packets between ingress and egress points over PW.

•When the ATM interface is shut down, all the VCs and VPs configured on the interface are disconnected from the driver, resulting in blocking of all traffic including VCCV and data traffic.

How to Configure ATM Attachment Circuit—VC Signaling and Provisioning

This section contains the following procedure:

•Configuring ATM Attachment Circuit—VC Signaling and Provisioning

Configuring ATM Attachment Circuit—VC Signaling and Provisioning

Perform this task to configure the ATM Attachment Circuit—VC Signaling and Provisioning feature.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface atm interface-number/slot/port

4. atm asynchronous

5. atm mcpt-timers timer1 timer2 timer3

6. cell-packing maxcells mcpt-timer timer-number

7. xconnect peer-ipaddress vc-id encapsulation mpls

8. xconnect peer-ipaddress vc-id pw-class pw-class-name

9. end

10. show atm [vc | vp]

11. show atm [vc | vp] detail

DETAILED STEPS

Command or Action

Purpose

Step 1

enable

Example:

Router> enable

Enables privileged EXEC mode.

•Enter your password if prompted.

Step 2

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3

interface atm interface-number/slot/port

Example:

Router(config)# interface atm 2/0/0

Enables the ATM interface. Enter the interface number, the slot number and port number.

Step 4

atm asynchronous

Example:

Router(config-if)# atm asynchronous

Enable the ATM Asynchronous feature.

Step 5

atm mcpt-timers timer1 timer2 timer3

Example:

Router(config-if)# atm mcpt-timers 100 1000 1000

(Only for AAL0 encapsulation) Sets Martini Cell Packing Timer (MCPT) values in microseconds. The range for timer1 and timer2 is 10 to 4095. The range for timer 3 is 20 to 4095.

MCPT timer sets the time that the router waits for the raw cells (AAL0 encapsulation) to be packed into a single packet for punting into the pseudowire.

Step 6

cell-packing maxcells mcpt-timer timer-number

Example:

Router(config-if)# cell-packing 20 mcpt-timer 2

Enables ATM over MPLS to pack multiple ATM cells into each MPLS packet within the MCPT timing.

Step 7

xconnect peer-ipaddress vc-id encapsulation mpls

Example:

Router(config-if)# xconnect 22.22.22.22 101 encapsulation mpls

Enables the attachment circuit. Specify the IP address of the peer, and a VC ID. The range of the VC ID is from 1 to 4294967295. You must also specify the data encapsulation method, in this case MPLS.

Step 8

xconnect peer-ipaddress vc-id pw-class pw-class-name

Example:

Router(config-if)# xconnect 22.22.22.22 101 pw-class BFD_dyn

(Optional) Specifies the pseudowire class for advanced configuration. Enables the attachment circuit. Specify the IP address of the peer, and a VC ID. The range of the VC ID is from 1 to 4294967295.

Step 9

end

Example:

Router(config-if-xconn)# end

Exits Xconnect configuration mode and returns to global configuration mode.

Step 10

show atm [vc | vp]

Example:

Router# show atm vc

Displays ATM VC or VP information.

Step 11

show atm [vc | vp] detail

Example:

Router# show atm vc detail

Displays details of ATM VC or VP states.

Configuration Examples for ATM Attachment Circuit—VC Signaling and Provisioning

•Example: Configuring ATM Attachment Circuit—VC Signaling and Provisioning Feature

•Example: Verifying the VP States

•Example: Verifying the VC States

Example: Configuring ATM Attachment Circuit—VC Signaling and Provisioning Feature

This example shows the configuration on the PE router:
Router# interface ATM1/0/0
Router(config-if)# no ip address
Router(config-if)# no atm enable-ilmi-trap
Router(config-if)# pvc 2/210 l2transport
Router(config-if)# xconnect 3.1.1.3 1010 pw-class BFD_dyn
Router(config-if-xconn)# end
Example: Verifying the VP States
This example shows the output of the show atm vp command and lists the statistics for all VPs on an 
interface:
Router# show atm vp
                             Data  CES    Peak     CES Avg/Min Burst     MCR
Interface     VPI SC          VCs  VCs    Kbps    Kbps    Kbps Cells    Kbps    CDVT  
Status
1/1/0          29               0    0  149760       0     N/A   N/A     N/A     N/A  
ACTIVE  
1/1/0          40               0    0  149760       0     N/A   N/A     N/A     N/A  
ACTIVE  
1              90               0    0  149760       0     N/A   N/A     N/A     N/A  
INACTIVE
10             25               0    0  149760       0     N/A   N/A     N/A     N/A  
INACTIVE
10             30               0    0  149760       0     N/A   N/A     N/A     N/A  
INACTIVE
Example: Verifying the VC States
When the ATM interface is shut down, the VCs go into inactive state. This example shows the output 
of the show atm vc command that lists VC states:
Router# show atm vc
Codes: DN - DOWN, IN - INACTIVE 
           VCD /                                            Peak Av/Min Burst
Interface  Name         VPI   VCI Type    Encaps     SC     Kbps   Kbps Cells St
1/1/0      1              2   200 PVC     AAL5       UBR  149760              UP
1/1/0      2             29     3 PVC     F4-OAM     UBR  149760              UP
1/1/0      3             29     4 PVC     F4-OAM     UBR  149760              UP
1/1/0      4             40     3 PVC     F4-OAM     UBR  149760              UP
1/1/0      5             40     4 PVC     F4-OAM     UBR  149760              UP
3/1/0      1              1   200 PVC     AAL0       UBR  149760              UP
This example shows the output of the show atm vc detail command that lists the details of VC states:
Router# show atm vc detail
ATM4/0/0: VCD: 1, VPI: 2, VCI: 200
::
Status: INACTIVE
Async Status: SETUP_COMP, Admin Status: DISABLED, Flags: Setup 
	
ATM4/0/0: VCD: 1, VPI: 2, VCI: 200
::
Status: UP
Async Status: SETUP_COMP, Admin Status: ENABLED, Flags: Enable 
Additional References

Related Documents

Related Topic

Document Title

Cisco IOS commands

Cisco IOS Master Commands List, All Releases

ATM commands

Cisco IOS Asynchronous Transfer Mode Command Reference

Standards

Standard

Title

None

MIBs

MIB

MIBs Link

None

To locate and download MIBs for selected platforms, Cisco software releases, and feature sets, use Cisco MIB Locator found at the following URL:

http://www.cisco.com/go/mibs

RFCs

RFC

Title

None

Technical Assistance

Description

Link

The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

http://www.cisco.com/cisco/web/support/index.html

Feature Information for ATM Attachment Circuit—VC Signaling and Provisioning

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 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 software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Table 1 Feature Information for ATM Attachment Circuit—VC Signaling and Provisioning

Feature Name

Releases

Feature Information

ATM Attachment Circuit—VC Signaling and Provisioning

15.0(1)S

The ATM Attachment Circuit—VC Signaling and Provisioning feature ensures that the data plane is active on the PE box, the BFD VCCV or control packets are passed on to the peer within the MPLS core (PE to PE MPLS cloud), and the smooth flow of data traffic.

Cisco and the Cisco Logo are trademarks of Cisco Systems, Inc. and/or its affiliates in the U.S. and other countries. A listing of Cisco's trademarks can be found at www.cisco.com/go/trademarks. Third party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1005R)

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.

© 2010 Cisco Systems, Inc. All rights reserved.

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. •Enter your password if prompted.
Step 2	configure terminal Example: Router# configure terminal	Enters global configuration mode.
Step 3	interface atm interface-number/slot/port Example: Router(config)# interface atm 2/0/0	Enables the ATM interface. Enter the interface number, the slot number and port number.
Step 4	atm asynchronous Example: Router(config-if)# atm asynchronous	Enable the ATM Asynchronous feature.
Step 5	atm mcpt-timers timer1 timer2 timer3 Example: Router(config-if)# atm mcpt-timers 100 1000 1000	(Only for AAL0 encapsulation) Sets Martini Cell Packing Timer (MCPT) values in microseconds. The range for timer1 and timer2 is 10 to 4095. The range for timer 3 is 20 to 4095. MCPT timer sets the time that the router waits for the raw cells (AAL0 encapsulation) to be packed into a single packet for punting into the pseudowire.
Step 6	cell-packing maxcells mcpt-timer timer-number Example: Router(config-if)# cell-packing 20 mcpt-timer 2	Enables ATM over MPLS to pack multiple ATM cells into each MPLS packet within the MCPT timing.
Step 7	xconnect peer-ipaddress vc-id encapsulation mpls Example: Router(config-if)# xconnect 22.22.22.22 101 encapsulation mpls	Enables the attachment circuit. Specify the IP address of the peer, and a VC ID. The range of the VC ID is from 1 to 4294967295. You must also specify the data encapsulation method, in this case MPLS.
Step 8	xconnect peer-ipaddress vc-id pw-class pw-class-name Example: Router(config-if)# xconnect 22.22.22.22 101 pw-class BFD_dyn	(Optional) Specifies the pseudowire class for advanced configuration. Enables the attachment circuit. Specify the IP address of the peer, and a VC ID. The range of the VC ID is from 1 to 4294967295.
Step 9	end Example: Router(config-if-xconn)# end	Exits Xconnect configuration mode and returns to global configuration mode.
Step 10	show atm [vc \| vp] Example: Router# show atm vc	Displays ATM VC or VP information.
Step 11	show atm [vc \| vp] detail Example: Router# show atm vc detail	Displays details of ATM VC or VP states.

Related Topic	Document Title
Cisco IOS commands	Cisco IOS Master Commands List, All Releases
ATM commands	Cisco IOS Asynchronous Transfer Mode Command Reference

Standard	Title
None

MIB	MIBs Link
None	To locate and download MIBs for selected platforms, Cisco software releases, and feature sets, use Cisco MIB Locator found at the following URL: http://www.cisco.com/go/mibs

RFC	Title
None

Description	Link
The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies. To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds. Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.	http://www.cisco.com/cisco/web/support/index.html

Table 1 Feature Information for ATM Attachment Circuit—VC Signaling and Provisioning
Feature Name	Releases	Feature Information
ATM Attachment Circuit—VC Signaling and Provisioning	15.0(1)S	The ATM Attachment Circuit—VC Signaling and Provisioning feature ensures that the data plane is active on the PE box, the BFD VCCV or control packets are passed on to the peer within the MPLS core (PE to PE MPLS cloud), and the smooth flow of data traffic.

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