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SYSTEM ADMINISTRATOR GUIDE 13/1543-CRA 119 1170/1-V1 Uen C | ![]() |
Copyright
© Ericsson AB 2009–2010. All rights reserved. No part of this document may be reproduced in any form without the written permission of the copyright owner.
Disclaimer
The contents of this document are subject to revision without notice due to continued progress in methodology, design and manufacturing. Ericsson shall have no liability for any error or damage of any kind resulting from the use of this document.
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SmartEdge | is a registered trademark of Telefonaktiebolaget LM Ericsson. | |
NetOp | is a trademark of Telefonaktiebolaget LM Ericsson. |
This document describes how to configure, monitor, and administer Automatic Protection Switching (APS) and multiplex section protection (MSP) on Packet over SONET/SDH (POS) and second-generation Asynchronous Transfer Mode (ATM) OC ports.
Besides providing facility protection for traffic on the optical fiber ports, APS and MSP on the SmartEdge router provide equipment protection for the traffic card hosting the working port. If the traffic card fails and the protect port is on another traffic card, the SmartEdge OS switches the affected traffic to the protect port and allows the failed card to be serviced. APS and MSP also provide protection against line faults or failures for ATM OC ports.
The SmartEdge OS supports a subset of Synchronous Optical Network/Synchronous Digital Hierarchy (SONET/SDH) APS that is described in the Telcordia publication GR-253-CORE, SONET Transport Systems, Common Criteria, Section 5.3 and the SDH specification described in ITU-T Recommendation G..783. MSP is described in ITU-T Recommendation G.841. Annex B of ITU-T G.841 is not supported.
The SmartEdge OS implementation of APS and MSP is linear 1+1 and has the following features and configuration requirements:
If you configured an APS/MSP group for revertive switching and the working port becomes available after a switch to the protect port, the working port enters the wait to restore (WTR) state. If the working port remains clear throughout the WTR interval, a switch back to the working port occurs when the WTR interval expires. Both POS and ATM ports support revertive and nonrevertive switching.
Caution! | ||
Risk of service disruption. When an APS or MSP working or protect
port is removed (unconfigured) from an APS/MSP group, all sessions
currently active on the ports are terminated. Only sessions configured
on the working port can be brought back up as normal. To reduce the
risk of service disruption beyond this temporary termination of sessions
when you unconfigure a working or protect port from an APS/MSP group,
do not remove either the working or protect port without first performing
an APS/MSP aps switch force command on
the active port to switch all sessions to the working port and locking
out the protect port.
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When the working and protect Automatic Protection Switching (APS) ATM ports are on different slots, and when traffic has to traverse the (Advanced Services Engine) ASE card for services such as Deep Packet Inspection (DPI), the ASE card replicates traffic going towards the ports in the APS/MSP group.
Use the show security asp command with the statistics keyword when examining the operating statistics of this feature.
The term APS configuration used in this document and other documents in the SmartEdge OS Library refers to the configuration of both APS and MSP groups.
The term traffic card refers to a SmartEdge 100 media interface card (MIC) or a SmartEdge 400 or SmartEdge 800 traffic card, unless otherwise noted.
To configure an APS/MSP group, perform the tasks described in Table 1; enter all commands in APS configuration mode, unless otherwise noted.
Step |
Task |
Root Command |
Notes |
---|---|---|---|
1. |
Create an APS/MSP group or select one for modification, and access APS configuration mode. |
Enter this command in global configuration mode. Specify either ATM or POS as the group type. The default type is POS. | |
2. |
Set the mode for the APS/MSP group |
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3. |
Associate a description with the group. |
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4. |
Optional. Specify the revertive switching algorithm and WTR interval. |
The default algorithm is nonrevertive. |
Before you can assign a port as a working port in an APS/MSP group, the group must first be created. After the APS/MSP group is created, assign the working and protect ports to it in any order.
The following requirements apply to the port configuration:
To assign a port to an APS/MSP group, enter the aps command with either the working or protect keyword. Table 2 summarizes the task. You can add ports in any order. Enter the aps command in port configuration mode.
Task |
Root Command |
Notes |
---|---|---|
Assign the port to the APS/MSP group. |
Use either the working or protect keyword. Ports must have the same type and framing. This command enables APS for SONET framed ports and MSP for SDH framed ports. |
To manage the ports in an APS group, perform one or more of the tasks described in Table 3. Enter all commands in port configuration mode unless otherwise noted.
Task |
Root Command |
Notes |
---|---|---|
Request a lockout of the protect port. |
Use the lockout keyword. | |
Request a high-priority (forced) switch of either the working or protect port. |
Use the forced keyword. | |
Request a low-priority (manual) switch of either the working or protect port. |
Use the manual keyword. | |
Remove a posted request. |
Use the no form to remove a posted request. | |
Remove (unconfigure) an ATM port from a group. |
See Section 3.4.3 |
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Remove (unconfigure) a POS port from a group. |
See Section 3.4.1 |
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Replace an ATM port in a group. |
See Section 3.4.4. |
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Replace a POS port in a group. |
See Section 3.4.2”. |
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Shut down an ATM port in a group. |
See Section 3.4.5 |
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Delete a group. |
Enter this command in global configuration mode. Use the no form to delete the group. |
Before you delete a POS port from an APS/MSP group (that is, before you change its configuration so that it no longer belongs to the group), enter the show aps command with the detail keyword (in any mode) to determine the status of the working and protect ports. To remove a POS port from an APS/MSP group, perform the tasks described in Table 4. Enter all commands in port configuration mode.
Caution! | ||
Risk of service disruption. When you delete a POS working or protect
port from an APS/MSP group, all sessions currently active on the port
are terminated. Only sessions on the working port can be brought back
up as normal. To reduce the risk of service disruption beyond this
temporary termination of sessions when deleting a POS working or protect
port from an APS/MSP group, perform one of the procedures provided
in Table 4. Otherwise, the system might enter an
undesirable state.
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Before you replace a POS port in an APS/MSP group, enter the show aps command with the detail keyword (in any mode) to determine the traffic status of the working and protect ports; perform the tasks in Table 5.
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To remove either the ATM working or protect port from an APS/MSP group (that is, to configure it so that it no longer belongs to the group), enter the no form of the aps command (in port configuration mode). When you delete an ATM working or protect port from an APS/MSP group, the system also removes the other port.
To replace either the ATM working or protect port from an APS/MSP group, first delete the port from the group (that is, configure it so that it no longer belongs to the group): enter the no form of the aps command (in port configuration mode).
Then, add the new ATM working and protect ports to the group: enter the aps command (in port configuration mode). Either of these ports can be one of the ports you previously deleted.
Finally, reconfigure the ATM working port that you have added to the APS/MSP group; the system automatically replicates its configuration for the protect port.
To shut down an ATM working or protect port, perform the tasks described in Table 6.
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(1) An LOS condition
detected on the working port has a lower priority than a lockout switch.
Therefore, if an LOS occurs on the working port during this procedure,
packets are lost.
(2) An LOS condition detected on the protect port
has a higher priority than a forced switch. Therefore, if an LOS occurs
on the protect port during this procedure, traffic is switched back
to the working port and packets are lost.
You can change the configuration of a working port while it is a member of an APS/MSP group, but you must ensure that the configuration of the protect port is identical to that of the working port:
If you must replace a POS or an ATM traffic card (remove it from the chassis and install a new traffic card) and that traffic card has one or more ports that are active in an APS/MSP group, perform the following procedure:
Caution! | ||
If the working and protect ports are both on the same traffic card, this procedure is immaterial; all sessions are lost when the traffic card is removed from the chassis. Ensure that you enter the commit command after each configuration command and display the port APS/MSP status with the show aps command after each command is committed. |
To display Automatic Protection Switching (APS) information for one or more APS groups, perform the tasks listed in Table 7. Enter the show command in any mode.
Task |
Root Command |
---|---|
Display the status of one or more APS groups and their working and protect ports. |
The following example shows how to create the APS/MSP group lab48 with revertive switching and a WTR of 10 minutes, configure the ports on two OC-48c/STM-16c cards for the group, and add them to the group:
[local]Redback(config)#aps group lab48 pos [local]Redback(config-aps)#architecture 1+1 bidirectional [local]Redback(config-aps)#revert 10 [local]Redback(config-aps)#exit [local]Redback(config)#port pos 1/1 [local]Redback(config-port)#encapsulation cisco-hdlc [local]Redback(config-port)#aps working lab48 [local]Redback(config-port)#bind interface if-lab48 local [local]Redback(config-port)#no shutdown [local]Redback(config-port)#exit [local]Redback(config)#port pos 2/1 [local]Redback(config-port)#encapsulation cisco-hdlc [local]Redback(config-port)#aps protect lab48 [local]Redback(config-port)#no shutdown [local]Redback(config-port)#exit
The following example shows how to temporarily disable APS/MSP switching on port 3/1 (the protect port) by requesting a lockout:
[local]Redback(config)#port pos 3/1 [local]Redback(config-port)#aps switch lockout
The following example shows how to re-enable switching by removing the lockout request:
[local]Redback(config)#port pos 3/1 [local]Redback(config-port)#no aps switch lockout
The following example shows how to post a high-priority request to switch the sessions on working port 2/1 to the protect port:
[local]Redback(config)#port pos 2/1 [local]Redback(config-port)#aps switch force
The following example shows how to remove the high-priority request. Because the switching algorithm for the APS/MSP group is revertive, port 2/1 becomes the working port for the APS/MSP group after the WTR interval expires and no alarms have been posted against it:
[local]Redback(config)#port pos 2/1 [local]Redback(config-port)#no aps switch force
The following example shows how to post a low-priority request to switch the sessions on working port 2/1 to the protect port:
[local]Redback(config)#port pos 2/1 [local]Redback(config-port)#aps switch manual
For the request to succeed, no higher-priority APS/MSP requests must be in effect.
The following example shows how to remove the low-priority request. Because the switching algorithm for the APS/MSP group is revertive, port 2/1 becomes the working port for the APS/MSP group after the WTR interval expires and no alarms have been posted against it:
[local]Redback(config)#port pos 2/1 [local]Redback(config-port)#no aps switch manual
The following example shows how to create an MSP group for CLIPS over ATM POS:
[local]Redback(config)#aps group atm-msp atm [local]Redback(config-aps)#revert 5 [local]Redback(config-aps)#architecture 1+1 bidirectional [local]Redback(config-aps)#end !... [local]Redback(config)#port atm 4/1 [local]Redback(config-atm-oc)#framing sdh [local]Redback(config-atm-oc)#no shutdown [local]Redback(config-atm-oc)#aps working atm-msp [local]Redback(config-atm-oc)#atm pvc 1 32 profile ubr encapsulation bridge1483 [local]Redback(config-atm-pvc)#service clips dhcp context local [local]Redback(config-atm-pvc)#end !... [local]Redback(config)#port atm 11/1 [local]Redback(config-atm-oc)#framing sdh [local]Redback(config-atm-oc)#no shutdown [local]Redback(config-atm-oc)#aps protect atm-msp [local]Redback(config-atm-oc)#end