Introduction
This document describes the steps required to perform a switchover of Synchronous Transport Module (STM)/OC3 card on Cisco ASR5000.
Background Information
The STM1/OC3 cards on ASR5000 provide STM-1 ports and therefore require to be handled with special care.
The STM-1 (level-1) is the Synchronous Digital Hierarchy (SDH) ITU-T fiber optic network transmission standard. It has a bit rate of 155.52 Mbit/s.
SDH is different from Ethernet and has some specifics that must be taken into consideration.
Problem
The setup has a pair of STM1/OC3 cards configured with Automatic Protection Switching (APS) mode redundancy - card 21 and card 37. The card 37 is active and card 21 is standby. The ports 21/1 and 21/2 are Down and APS working. The 37/1 and 37/2 ports are up and APS protected.
card 21
redundancy aps-mode
aps 1+1 uni-directional non-revertive
framing sdh e1
initial-e1-framing crc4
service-type frame-relay
#exit
******** show card table all *******
Slot Card Type Oper State SPOF Attach
----------- -------------------------------------- ------------- ---- ------
21: LC 4 PORT STM1/OC3 Channelized Card Standby - 5
37: LC 4 PORT STM1/OC3 Channelized Card Active No 5
[local]gre2mme01# show aps info 37/1
Port :37/1
Role : Protected
Mode : 1+1
Revertive : No
State : Active
Direction : Uni
Wait To Restore(sec) : 0
Redundant Port : 21/1
Lockout : No
[local]gre2mme01# show aps info 21/1
Port :21/1
Role : Working
Mode : 1+1
Revertive : No
State : Standby
Direction : Uni
Wait To Restore(sec) : 0
Redundant Port : 37/1
Lockout : No
[local]mme01# show port table
Thursday March 08 11:20:20 CET 2018
Port Role Type Admin Oper Link State Pair Redundant
----- ---- ------------------------ -------- ---- ---- ------- ----- ---------
21/1 Srvc STM1/OC3 Channelized Enabled - Down Standby 37/1 APS Workn
21/2 Srvc STM1/OC3 Channelized Enabled - Down Standby 37/2 APS Workn
37/1 Srvc STM1/OC3 Channelized Enabled - Up Active 21/1 APS Protd
37/2 Srvc STM1/OC3 Channelized Enabled - Up Active 21/2 APS Protd
Tentatives of performing a switchover between cards 21 and 37 fail with "wrong redundancy mode" error.
[local]gre2mme01# card switch from 37 to 21
Friday March 09 00:28:10 CET 2018
Failure: wrong redundancy mode
Solution
The switchover with card switch from X to Y is not supported for STM1/OC3 cards with APS mode redundancy.
APS specific commands must be used instead.
aps { clear slot#/port# | exercise slot#/port# | lockout slot#/port# | switch { force | manual } slot#/port# }
switch { force | manual } slot#/port#
Switch to either the working port or the protection port:
force: Forces a switch of ports, even if there is an active alarm state.
manual: Implements a switch of ports if there are no active alarms.
slot#/port# is the CLC2/OLC2 slot number (valid range is 17 - 48) and appropriate port number (CLC2 valid range is 1 - 4; OLC2 valid value is 1)
In this case, the problem was solved with:
aps switch manual 37/1
aps switch manual 37/2
Note: If the manual switchover fails, it can be because of errors on the port. Verify the port status with "show aps port-status <card/slot>". The switchover can be still forced with the "force" option.
[local]gre2mme01# show aps port-status 21/1
Friday March 09 13:19:49 CET 2018
Port : 21/1
Role : Working
Lockout : No
APS Signal Failure : No
APS Signal Degrade : No
Switch Over : No
Far End Failiure : No
Remote Not Compatible : No
Current Command : No Request
Switch Status : No request
[local]gre2mme01#
[local]gre2mme01# show aps port-status 37/1
Friday March 09 13:20:07 CET 2018
Port : 37/1
Role : Protected
Lockout : No
APS Signal Failure : No
APS Signal Degrade : No
Switch Over : No
Far End Failiure : No
Remote Not Compatible : No
Current Command : No Request
Switch Status : No request
Invalid K1 K2 : No
Rx K1 : Reqest : 0x 0 (-- Channel - 0)
Rx K2 : Status : 0x 0 (-- Channel - 0)
Tx K1 : Reqest : 0x 0 (No Request Channel - 0)
Tx K2 : Status : 0x 4 (UNI,1+1 Channel - 0)
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