Configuring OAM

This section explains:

• Configuring F4 OAM
• Configuring F5 OAM
• Setting a Loopback Location ID
• Enabling OAM Flush
• Running ATM Ping

Configuring F4 OAM

The ATM interface does not support sending F4 segment loopback cells, but it does respond to F4 segment loopback cells that it receives.

F4 OAM flows need their own channel, and they are identified by the VCI on which they are sent or received. The following VCIs are reserved for F4 OAM flows for each virtual path, and you cannot open PVCs on them:

• VCI 3—For segment F4 flows
• VCI 4—For end-to-end F4 flows

  Note: You cannot enable both loopback cells and CC cells at the same time.

To set up F4 OAM:

1. Enable F4 OAM on an interface or VP. The router enables F4 OAM at the interface level unless you specify a VPI. This example opens both segment and end-to-end F4 OAM circuits on VPI 10.

   host1(config-if)#atm oam 10

2. (Optional) Enable only segment or end-to-end loopback.

   host1(config-if)#atm oam 10 seg-loopback

   host1(config-if)#atm oam 10 end-loopback

3. (Optional) To cause the interface to generate end-to-end loopback cells in addition to receiving and responding to them, set the loopback timer.

   host1(config-if)#atm oam 10 end-loopback loopback-timer 20

4. (Optional) Enable CC cell flows.

   host1(config-if)#atm oam 10 seg-loopback cc source

atm oam

• Use to configure F4 OAM on an interface or circuit. F4 OAM is configured at the interface level unless you specify a VPI.
• To open F4 OAM on either a segment or end-to-end basis, use the following keywords:
  • seg-loopback—Enables F4 segment OAM
  • end-loopback—Enables F4 end-to-end OAM

    Note: If you do not specify either segment or end-to-end loopback, the command applies to both end-to-end and segment F4 OAM circuits.

• To configure CC cell flow on the PVC, use the following keywords:
  • both—Enables the PVC as both the source and the sink endpoints.
  • sink—Enables the PVC as the sink endpoint.
  • source—Enables the PVC as the source endpoint.
  • loopback-timer—When F4 OAM is enabled, the interface or circuit accepts and responds to F4 OAM cells. However, to generate F4 loopback cells, you must configure the loopback timer in the range 1–600 seconds. This timer represents the frequency with which F4 loopback cells are transmitted. You can set the loopback timer only for end-to-end loopback.
• Example 1—Opens both F4 end-to-end and segment OAM circuits for VPI 8

  host1(config-if)#atm oam 8

• Example 2—Opens the F4 end-to-end OAM circuit for VPI 10 and enables sending F4 end-to-end loopback cells on the circuit at a frequency of 20 seconds

  host1(config-if)#atm oam 10 end-loopback loopback-timer 20

• Example 3—Opens both F4 end-to-end and segment OAM circuits on all VPs on this interface

  host1(config-if)#atm oam

• Example 4—Opens F4 segment OAM circuits on all VPs on this interface

  host1(config-if)#atm oam seg-loopback

• Example 5—Opens F4 end-to-end loopback on VPI 12

  host1(config-if)#atm oam 12 end-loopback

• Example 6—Opens an F4 segment OAM circuit for VPI 8 and enables CC cell generation on the segment

  host1(config-if)#atm oam 8 seg-loopback cc source

• Use the no version to delete F4 OAM circuits. Using the options, you can delete all F4 OAM circuits on the interface, segment or end-to-end F4 OAM circuits, or F4 OAM circuits on a specific VPI.
  • Example 1—Deletes all F4 OAM circuits on the interface

    host1(config-if)#no atm oam

  • Example 2—Deletes all F4 segment OAM circuits on the interface

    host1(config-if)#no atm oam segment

  • Example 3—Deletes the F4 end-to-end OAM circuit on VPI 8

    host1(config-if)#no atm oam 8 end-loopback

• See atm oam.

Configuring F5 OAM

F5 OAM flows run over existing PVCs. The ATM interface does not support sending F5 segment loopback cells, but it does respond to F5 segment loopback cells that it receives.

Note: You cannot enable both loopback cells and CC cells at the same time.

To set up F5 OAM:

1. To enable VC integrity, which causes the ATM interface to periodically send F5 end-to-end loopback cells over a VC, use the oam keyword with the atm pvc command.

   You can include the frequency (in seconds) with which the router sends F5 end-to-end loopback cells.

   host1(config-if)#atm pvc 98 38 22 aal5snap oam 300

2. (Optional) To enable CC cell flows on a circuit, use the cc keyword with the atm pvc command. You can enable cell flows on a segment or end-to-end basis, and you can enable the PVC as a sink, source, or both a sink and a source.

   host1(config-if)#atm pvc 50 0 50 aal5snap oam cc end-to-end sink

When you issue the appropriate shutdown command to change the administrative status of the corresponding ATM interface, ATM AAL5 interface, or ATM 1483 subinterface from enabled to disabled, the router automatically disables all F5 OAM services configured on the associated VC. For more information, see Automatic Disabling of F5 OAM Services.

atm pvc

• Use the atm pvc command with the oam keyword to set up the PVC to periodically transmit F5 end-to-end loopback cells over a VC.
• You can use the oam keyword only if you specify one of the following encapsulation types:
  • aal5snap
  • aal5mux ip
  • aal5autoconfig
• The oam keyword is not available with the aal5all, aal0, or ilmi
• Optionally, you can configure the time interval in the range 1–600 seconds between transmissions of OAM F5 end-to-end loopback cells.
• Use the following keywords to enable and configure CC cell flows:
  • end-to-end—Opens an end-to-end CC cell flow
  • segment—Opens a segment CC cell flow
  • sink—Enables this VC as a sink point (cell receiver)
  • source—Enables this VC as the source point (cell generator)
  • both—Enables this VC as both a sink point and a source point
• Example 1—Enables F5 end-to-end loopback cells

  host1(config-if)#atm pvc 20 20 20 aal5snap oam

• Example 2—Enables end-to-end CC cell flow and enables the PVC as the sink

  host1(config-if)#atm pvc 5 0 5 aal5autoconfig oam cc end-to-end sink

• Use the no version of the atm pvc command without the oam keyword to disable F5 OAM on the PVC and without the cc keyword to disable CC cell flows on the PVC. For example, the following command disables CC cell flow configured in Example 2.

  host1(config-if)#no atm pvc 5 0 5 aal5autoconfig

• See atm pvc.

Setting a Loopback Location ID

To enable other nodes to specifically send OAM loopback cells to the ATM interface, set the location ID of the ATM interface or circuit.

Note: Because the router is a connection endpoint, the default loopback location ID is all 1s (ones). This command enables you to specify a nondefault value.

atm oam loopback-location

• Use to set the location ID of the ATM interface. The location ID is a 4-octet field, and the default value is all 1s (ones).
  • You can set a specific value to identify this ATM interface as the intended recipient of OAM loopback cells.
  • You can also set the location ID to all 0s (zeros).

  For information about how the router handles loopback cells based on location ID, see Table 6.

• Example

  host1(config-if)#atm oam loopback-location 01090708

• Use the no version to return the loopback location ID to the default value, all 1s (ones).
• See atm oam loopback-location.

Enabling OAM Flush

You can use the atm oam flush command to enable the OAM flush feature for an ATM interface. When OAM flush is enabled, the router ignores all OAM cells received on the interface, and stops sending OAM cells on this interface.

You can also issue the atm oam flush command with the optional alarm-cells keyword to cause the router to ignore only AIS and RDI cells and to accept all other OAM cells. This is useful in diagnostic situations when you might want to exclude alarm conditions.

Note: The OAM flush feature is supported on all E-series ATM module combinations.

atm oam flush

• Use to configure the router to ignore all OAM cells received on an ATM interface, and to stop sending OAM cells on this interface.
• To cause the router to ignore only AIS and RDI cells and to accept all other OAM cells, use the alarm-cells keyword.
• Example

  host1(config-if)#atm oam flush

• Use the no version to disable OAM flush on the interface.
• See atm oam flush.

Running ATM Ping

Keep in mind the following when you use ATM ping:

• Before you can run ATM ping, you need to add a PVC for the VPI and VCI over which you run the ping.
• Because ATM ping requires the receipt of OAM cells, make sure that the receipt and transmission of OAM cells is not disabled (using atm oam flush ). To reenable the receipt and transmission of OAM cells, enter no atm oam flush.
• Disabling receipt of OAM cells during a ping operation stops all outstanding ping operations. You need to manually restart the ping operation after receipt of OAM cells for the interface is enabled.
• Because ATM ping is a dynamic (on-demand) operation, none of the configuration related to ATM ping is saved. To avoid acquiring excessive bandwidth for OAM, the number of outstanding ping operations on each interface is limited to 12.

ping atm interface atm

• Use to send loopback cells from an ATM interface or circuit.
• The VPI and VCI fields determine the type of loopback cells used for the ping operation. By default F5 end-to-end loopback OAM cells are used.
  • To send F4 segment loopback cells, set the VCI to 3.
  • To send F4 end-to-end loopback cells, set the VCI to 4.
• Use the end-loopback keyword to send the ping to the connection endpoint.
• Use the seg-loopback keyword to send the ping to the first segment point (for example, the next neighbor switch).
• Use the destination option to specify the value of the location ID included in the loopback cell. The location ID is a 16-octet field, and the destination portion is 4 octets. You can set the location ID to a specific destination or to 0s (zeros) or 1s (ones).
  • If you set the destination to 0, the loopback location ID in the loopback cell is initialized to all 0s, and each segment point in the network responds to the ping.
  • If you set the destination to 1s, the loopback location ID in the loopback cell is initialized to all 1s, and only the connection endpoint responds to the ping.
  • If you use the default value of 0xFFFFFFFF, the loopback location ID in the loopback cell is initialized to all 1s.

  For information about how the router handles loopback cells based on location ID, see Table 6.

• The count keyword sets the number of OAM loopback cells to send to the destination. The default value is 5. The maximum is 32.
• The timeout keyword sets the amount of time to wait for a response to the sent OAM loopback cell. The default value is 5 seconds.
• The following characters can appear in the display after the ping command has been issued:
  • !—Each exclamation point indicates that a reply was received
  • .—Each period indicates that the ping timed out while waiting for a reply
• Example 1—This example generates end-to-end loopback cells for VPI=0 and VCI=105 on ATM interface 2/0. The count value is 5 OAM loopback cells, and the timeout value is 2 seconds.

  host1#ping atm interface atm 2/0 0 105 end-loopback count 5 timeout 2

  Sending 5 53-byte OAM end-to-end loopback Echoes timeout is 2 secs

  Press Ctrl+c to stop

  !!!!!

  Success rate = 100% (5/5), round-trip min/avg/max = 0/4/10 ms

• Example 2—This example generates segment loopback cells for VPI=0 and VCI=105 on ATM interface 2/0. The destination is set to 0xFFFFFFFF, the count value is 3 OAM loopback cells, and the timeout value is 1 second.

  host1#ping atm interface atm 2/0 0 105 seg-loopback 0xFFFFFFFF count 3 timeout 1

  Sending 3 53-byte OAM segment loopback Echoes timeout is 1 secs

  Press Ctrl+c to stop

  !!!

  Success rate = 100% (3/3), round-trip min/avg/max = 0/3/10 ms

• There is no no version.
• See ping atm interface atm.

Copyright © 2009, Juniper Networks, Inc. All rights reserved. Trademark Notice.