Configuring Operation, Administration, and Maintenance

OAM Overview

Configuring OAM Functions

Configure OAM for the Entire Switch

Configure the Interface-Level OAM

Checking the ATM Connection

Displaying the OAM Configuration

Configuring Operation, Administration, and Maintenance

This chapter describes the Operation, Administration, and Maintenance (OAM) implementation on Cisco DSLAMs, and includes these sections:

OAM Overview

OAM performs fault management and performance management functions at the ATM management (M)-plane layer. The hardware provides both OAM cell filtering and OAM cell insertion support. The filtering and insertion capability is available on each configured circuit.

OAM cell processing is compliant with I.610; however, only fault management and loopback capabilities are available.

Note Current OAM implementation supports only the fault management function, which includes connectivity verification and alarm surveillance.

The DSLAM supports these ATM OAM cell flows:

F4 flows—OAM information flows between network elements (NEs) used within virtual paths to report an unavailable path or a virtual path (VP) that cannot be guaranteed. Segment flows are processed, as well as end-to-end flows that terminate in the management processor.
F5 flows—OAM information flows between network elements (NEs) used within virtual connections to report degraded virtual channel (VC) performance such as late arriving cells, lost cells, and cell insertion problems. Segment flows are processed, as well as end-to-end flows that terminate in the management processor.

Both F4 and F5 flows can be configured as either end-to-end or segment-loopback and used with alarm indication signal (AIS) and remote defect indication (RDI) functions.

Note Cells can be sent either on demand or periodically to verify link and connection integrity.

In addition to the standard OAM functions, the DSLAM can also send OAM pings. OAM cells containing the ATM node addresses or IP addresses of intermediate switches allow network administrators to determine the integrity of a chosen connection at any intermediate point along the connection, allowing for network connection debugging and troubleshooting.

OAM software implements ATM Layer F4 and F5 OAM fault management functions. OAM performs standard loopback (end-to-end or segment) and fault detection and notification (AIS and RDI) for each connection. It also maintains a group of timers for the OAM functions. When there is an OAM state change such as loopback failure, OAM software notifies the connection management software. The network operator can enable or disable OAM operation for these switch components:

The entire switch
A specific ATM interface
Each ATM connection

If OAM operation is disabled, outgoing OAM cells are not generated, and all incoming OAM cells are discarded.

To support various OAM operations, the DSLAM hardware provides OAM cell routing functions on a per-connection basis for each direction. These sections describe the OAM tasks:

Configuring OAM Functions

This section describes OAM commands in EXEC, global, and interface configuration mode.

Configure OAM for the Entire Switch

To enable OAM operations for the entire switch, use the global configuration command atm oam.

Note These configuration commands are not stored in the nonvolatile RAM (NVRAM).

Command
Task

atm oam [ais] [end-loopback] [intercept end-to-end] [max-limit number] [rdi] [seg-loopback]

OAM operations are enabled or disabled with respect to entire switch. Note: End-to-end is not supported in this release. Using it has no effect.

Command	Task
atm oam [ais] [end-loopback] [intercept end-to-end] [max-limit number] [rdi] [seg-loopback]	OAM operations are enabled or disabled with respect to entire switch. Note: End-to-end is not supported in this release. Using it has no effect.

Note The number of maximum OAM configured connections allowed ranges from 1 to 3200; the default is 3200.

Examples

This example shows how to enable AIS and segment loopback for the entire switch:

DSLAM(config)# atm oam ais seg-loopback
% OAM: Switch level seg loopback is enabled
 
% OAM: Switch level ais is enabled

This example shows how to configure the ATM OAM connection maximum to 1600:

DSLAM(config)# atm oam max-limit 1600

Configure the Interface-Level OAM

To enable OAM operations an interface, perform these steps, beginning in global configuration mode:

Step
Command
Task

1
interface atm slot/port[.vpt#]

Select the interface to be configured.

2
atm oam [vpi [vci] | interface atm slot/port[.vpt#]] [ais] [end-loopback]
[rdi] [seg-loopback]

Configure interface OAM operations.

3
atm oam vpi [vci] loopback-timer tx-timer-value

Configure the OAM loopback transmit timer.

Step	Command	Task
1	interface atm slot/port[.vpt#]	Select the interface to be configured.
2	atm oam [vpi [vci] \| interface atm slot/port[.vpt#]] [ais] [end-loopback] [rdi] [seg-loopback]	Configure interface OAM operations.
3	atm oam vpi [vci] loopback-timer tx-timer-value	Configure the OAM loopback transmit timer.

Note The OAM loopback command is hierarchial. You must first enable OAM at the global level then at the interface level before you can enable it on specific VCs.

Examples

This example shows how to enable OAM AIS end loopback on interface 0/1:

DSLAM(config)# interface atm 0/1
DSLAM(config-if)# atm oam ais end-loopback
% OAM: Interface level end to end loopback is enabled
 
% OAM: Interface level ais is enabled

The next example shows how to enable interface 0/1, VPI = 50, VCI = 100 to allow OAM AIS at the end and loopback:

DSLAM(config)# interface atm 0/1
DSLAM(config-if)# atm oam 50 100 ais end-loopback
% OAM: Connection level end to end loopback is not enabled
 
% OAM: Connection level ais is not enabled

Enable or disable OAM AIS, RDI, and loopback operations respective to a specified connection.

Note You can use only VPI values to turn on OAM operations on VP connections.

In interface configuration command mode, you can enable or disable OAM operations on existing connections on different interfaces by specifying interface atm slot/port. The third example enables OAM AIS flows at interface 0/1 level:

DSLAM(config)# interface atm 0/1
DSLAM(config-if)# atm oam ais
% OAM: Interface level ais is enabled

To view the result of this action, use the show atm vc interface command. This example displays the output you get for the ATM VC interface a0/1, with VPI = 0 and VCI = 500:

DSLAM# show atm vc interface a0/1 0 500
 
Interface: ATM0/1, Type: suni_dual 
VPI = 0  VCI = 500
Status: UP
Time-since-last-status-change: 01:35:46
Connection-type: PVC 
Cast-type: point-to-point
Packet-discard-option: disabled
Usage-Parameter-Control (UPC): pass
Number of OAM-configured connections: 6
OAM-configuration: Seg-loopback-on End-to-end-loopback-on
OAM-states:  OAM-Up End-to-end-loopback-up
OAM-Loopback-Tx-Interval: 5
Cross-connect-interface: ATM0/0, Type: ATM Swi/Proc 
Cross-connect-VPI = 0 
Cross-connect-VCI = 500
Cross-connect-UPC: pass
Cross-connect OAM-configuration: disabled
Cross-connect OAM-state:  Not-applicable
Encapsulation: AAL5SNAP
Rx cells: 1220, Tx cells: 0
Rx connection-traffic-table-index: 1
Rx service-category: UBR (Unspecified Bit Rate)
Rx pcr-clp01: 7113539
Rx scr-clp01: none
Rx mcr-clp01: none
Rx      cdvt: 1024 (from default for interface)
Rx       mbs: none
Tx connection-traffic-table-index: 1
Tx service-category: UBR (Unspecified Bit Rate)
Tx pcr-clp01: 7113539
Tx scr-clp01: none
Tx mcr-clp01: none
Tx      cdvt: none
Tx       mbs: none

Checking the ATM Connection

To check ATM connection reachability and network connectivity, use the EXEC command:

Step
Command
Task

1
configure [terminal]

At the privileged EXEC prompt, enter configuration mode from the terminal.

2
interface atm slot/port[.vpt#]

Select the interface.

3
ping atm interface atm slot/port vpi vci [atm-prefix prefix] | [end-loopback] | [ip-address address] | [seg-loopback]

Check the connection.

Step	Command	Task
1	configure [terminal]	At the privileged EXEC prompt, enter configuration mode from the terminal.
2	interface atm slot/port[.vpt#]	Select the interface.
3	ping atm interface atm slot/port vpi vci [atm-prefix prefix] \| [end-loopback] \| [ip-address address] \| [seg-loopback]	Check the connection.

You can use either an IP address or an ATM address prefix as a ping destination. You can also ping a neighbor switch or DSLAM by selecting the segment loopback option. In privileged EXEC mode, you can select various other parameters such as repeat count and timeout values.

Examples

This example shows the ping command used in normal mode to check a VCC with a segment loopback signal:

DSLAM# ping atm interface atm 0/1 50 100 seg-loopback
 
Type escape sequence to abort.
Sending Seg-Loopback 5, 53-byte OAM Echoes to a neighbor, timeout is 5 seconds:
.....
Success rate is 0 percent (0/5)

This example shows the ping command used in extended mode to check a VCC with a segment loopback signal:

DSLAM# ping
Protocol [ip]: atm
Interface [card/sub-card/port]: 0/1
VPI [0]: 0
VCI [0]: 16
Send OAM-Segment-Loopback ? [no]:
Target IP address:
Target NSAP Prefix:
Repeat count [5]:
Timeout in seconds [5]:
Type escape sequence to abort.
Sending end-Loopback 5, 53-byte OAM Echoes to a connection end point, timeout is
 5 seconds:
.....
Success rate is 0 percent (0/5)

Note If you skip both destination IP address and the ATM prefix fields, then extended ping considers its neighbor switch as its destination and a segment loopback OAM cell.

To display ATM statistics for each active port on the DSLAM, use the command show atm vc . For example,

DSLAM> show atm vc int atm 13/2 11

For each VC/VP the following displays:

Total Received Cells
Total Dropped Cells

To display port-specific ATM statistics, use the command show atm interface. For example,

DSLAM> show atm int 13/2

For each port the following displays:

Total Tx and Rx Cells
Dropped cells due to HEC error
Output port queue level (watermark)
Aggregate Counters
Discards due to invalid address
Input and output queue overflow
Exceeded contract violations (policing violations)
ATM Diagnostics

Displaying the OAM Configuration

To display the OAM configuration, use the EXEC command:

Command
Task

show running-config

Display the OAM configuration.

Command	Task
show running-config	Display the OAM configuration.

Example

The OAM configuration is displayed in this example:

DSLAM# show running-config
Building configuration...
 
Current configuration:
!
version XX.X
no service pad
service udp-small-servers
service tcp-small-servers
!
hostname DSLAM
!
boot system flash slot0:rhino/6260-wi-m_1.083.bin.Z
!
ip rcmd remote-username doug
atm oam max-limit 1600
atm over-subscription-factor 16
atm service-category-limit cbr 3000
atm qos uni3-default  cbr max-cell-loss-ratio 12
atm lecs-address 47.0091.0000.0000.0000.0000.0000.0000.0000.0000.00
atm address 47.0091.8100.0000.0060.3e5a.db01.0060.3e5a.db01.00
!
interface ATM0/0
 no keepalive
 map-group atm-1
 no atm auto-configuration
 no atm address-registration
 no atm ilmi-enable
 no atm ilmi-lecs-implied
 atm iisp side user
 atm pvp 99
 atm oam 0 5 seg-loopback  end-loopback  rdi
 atm oam 0 16 seg-loopback  end-loopback  rdi
 atm oam 0 18 seg-loopback  end-loopback  rdi
!
interface ATM0/0.99 point-to-point
 no atm auto-configuration
 no atm address-registration
 no atm ilmi-enable
 no atm ilmi-lecs-implied
 atm maxvp-number 0
 atm oam 99 5 end-loopback  rdi
 atm oam 99 16 end-loopback  rdi
 atm oam 99 18 end-loopback  rdi
!
interface ATM0/1
 no keepalive
 --More--
 
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