Configuring a Multichannel STM-1 on a Cisco router

When you have numerous E1 customers (> 8), you could terminate them on dedicated E1 ports of a router, e.g. with one or more  PA-MC-8E1/120 (EoL since 2003).
A more efficient way is to terminate them on a STM-1 port-adapter (e.g. a PA-MC-STM1), where you can aggregate up to 63 customers with one single fiber connection to the transport network (SDH).

When the port-adapter is inserted and recognized by the running IOS, you have to configure the “controller SONET“, before you can access the serial interfaces.

My example uses a Cisco 7206VXR (with NPE-G2) running c7200p-spservicesk9-mz.124-11.T1.bin.
Remark: This software is old, buggy and deprecated. If you want to run it in production, please choose a newer IOS.
The port-adapter used in Slot2/0 is a PA-MC-STM1-SMI (single mode flavor), which is connected to a SDH multiplexer (Marconi MS1/4).
There are no special SDH parameters (such as path-label and so on) configured.

Controller configuration

A minimum configuration for a SONET controller can look as shown in the following template.
In Germany, we have to configure “framing sdh”. In North America, you can omit the framing-statement.
The values for tug-3, tug-2 and e1 refers to the KLM values which describes the SDH multiplex structure according to ITU-T G.707.
For STM-1, you have only one au-4, a channelized STM-4 would give you four au-4.

controller SONET 2/0
 framing sdh
 !
 au-4 1 tug-3 1
  tug-2 1 e1 1 channel-group 0 timeslots 1-31
  tug-2 1 e1 2 channel-group 0 timeslots 1-31
  tug-2 1 e1 3 channel-group 0 timeslots 1-31
  tug-2 2 e1 1 channel-group 0 timeslots 1-31
  tug-2 2 e1 2 channel-group 0 timeslots 1-31
  tug-2 2 e1 3 channel-group 0 timeslots 1-31
  tug-2 3 e1 1 channel-group 0 timeslots 1-31
  tug-2 3 e1 2 channel-group 0 timeslots 1-31
  tug-2 3 e1 3 channel-group 0 timeslots 1-31
  tug-2 4 e1 1 channel-group 0 timeslots 1-31
  tug-2 4 e1 2 channel-group 0 timeslots 1-31
  tug-2 4 e1 3 channel-group 0 timeslots 1-31
  tug-2 5 e1 1 channel-group 0 timeslots 1-31
  tug-2 5 e1 2 channel-group 0 timeslots 1-31
  tug-2 5 e1 3 channel-group 0 timeslots 1-31
  tug-2 6 e1 1 channel-group 0 timeslots 1-31
  tug-2 6 e1 2 channel-group 0 timeslots 1-31
  tug-2 6 e1 3 channel-group 0 timeslots 1-31
  tug-2 7 e1 1 channel-group 0 timeslots 1-31
  tug-2 7 e1 2 channel-group 0 timeslots 1-31
  tug-2 7 e1 3 channel-group 0 timeslots 1-31
 !
 au-4 1 tug-3 2
  tug-2 1 e1 1 channel-group 0 timeslots 1-31
  tug-2 1 e1 2 channel-group 0 timeslots 1-31
  tug-2 1 e1 3 channel-group 0 timeslots 1-31
  tug-2 2 e1 1 channel-group 0 timeslots 1-31
  tug-2 2 e1 2 channel-group 0 timeslots 1-31
  tug-2 2 e1 3 channel-group 0 timeslots 1-31
  tug-2 3 e1 1 channel-group 0 timeslots 1-31
  tug-2 3 e1 2 channel-group 0 timeslots 1-31
  tug-2 3 e1 3 channel-group 0 timeslots 1-31
  tug-2 4 e1 1 channel-group 0 timeslots 1-31
  tug-2 4 e1 2 channel-group 0 timeslots 1-31
  tug-2 4 e1 3 channel-group 0 timeslots 1-31
  tug-2 5 e1 1 channel-group 0 timeslots 1-31
  tug-2 5 e1 2 unframed
  tug-2 5 e1 3 channel-group 0 timeslots 1-31
  tug-2 6 e1 1 channel-group 0 timeslots 1-31
  tug-2 6 e1 2 channel-group 0 timeslots 1-31
  tug-2 6 e1 3 channel-group 0 timeslots 1-31
  tug-2 7 e1 1 channel-group 0 timeslots 1-31
  tug-2 7 e1 2 channel-group 0 timeslots 1-31
  tug-2 7 e1 3 channel-group 0 timeslots 1-31
 !
 au-4 1 tug-3 3
  tug-2 1 e1 1 channel-group 0 timeslots 1-31
  tug-2 1 e1 2 channel-group 0 timeslots 1-31
  tug-2 1 e1 3 channel-group 0 timeslots 1-31
  tug-2 2 e1 1 channel-group 0 timeslots 1-31
  tug-2 2 e1 2 channel-group 0 timeslots 1-31
  tug-2 2 e1 3 channel-group 0 timeslots 1-31
  tug-2 3 e1 1 channel-group 0 timeslots 1-31
  tug-2 3 e1 2 channel-group 0 timeslots 1-31
  tug-2 3 e1 3 channel-group 0 timeslots 1-31
  tug-2 4 e1 1 channel-group 0 timeslots 1-31
  tug-2 4 e1 2 channel-group 0 timeslots 1-31
  tug-2 4 e1 3 channel-group 0 timeslots 1-31
  tug-2 5 e1 1 channel-group 0 timeslots 1-31
  tug-2 5 e1 2 channel-group 0 timeslots 1-31
  tug-2 5 e1 3 channel-group 0 timeslots 1-31
  tug-2 6 e1 1 channel-group 0 timeslots 1-31
  tug-2 6 e1 2 channel-group 0 timeslots 1-31
  tug-2 6 e1 3 channel-group 0 timeslots 1-31
  tug-2 7 e1 1 channel-group 0 timeslots 1-31
  tug-2 7 e1 2 channel-group 0 timeslots 1-31
  tug-2 7 e1 3 channel-group 0 timeslots 1-31
 description STM1 to SDH mux
!

Note: In normal case, we use E1 interfaces with framing according to G.704. For special cases, interfaces can configured as unframed (also known as unstructured –> G.703). If you need it, you also could channel the E1 lines down to DS0/D64S or use as fractional or channelized E1.

After inserting the template, the router creates the associated serial interfaces following the structure Serial<sonet-controller>.<au-4>/<tug-3>/<tu-2>/<vc-12>.
You can configure the generated interfaces like normal serial E1/T1 interfaces.

agg-r1#sh interfaces description | i ^In|^Se2
Interface                      Status         Protocol Description
Se2/0.1/1/1/1:0                admin down     down     test
Se2/0.1/1/1/2:0                up             up       test
Se2/0.1/1/1/3:0                up             up       test
Se2/0.1/1/2/1:0                up             up       test
Se2/0.1/1/2/2:0                down           down     unused
Se2/0.1/1/2/3:0                up             up       test
Se2/0.1/1/3/1:0                up             up       test
Se2/0.1/1/3/2:0                up             up       test
Se2/0.1/1/3/3:0                up             up       test
Se2/0.1/1/4/1:0                up             up       test
Se2/0.1/1/4/2:0                up             up       test
Se2/0.1/1/4/3:0                up             up       test
Se2/0.1/1/5/1:0                up             up       test
Se2/0.1/1/5/2:0                up             up       test
Se2/0.1/1/5/3:0                up             up       test
Se2/0.1/1/6/1:0                up             up       test
Se2/0.1/1/6/2:0                up             up       test
Se2/0.1/1/6/3:0                up             up       test
Se2/0.1/1/7/1:0                up             up       test
Se2/0.1/1/7/2:0                up             up       test
Se2/0.1/1/7/3:0                down           down     unused
Se2/0.1/2/1/1:0                up             up       test
Se2/0.1/2/1/2:0                up             up       test
Se2/0.1/2/1/3:0                up             up       test
Se2/0.1/2/2/1:0                up             up       test
Se2/0.1/2/2/2:0                down           down     unused
Se2/0.1/2/2/3:0                up             up       test
Se2/0.1/2/3/1:0                up             up       test
Se2/0.1/2/3/2:0                up             up       test
Se2/0.1/2/3/3:0                up             up       test
Se2/0.1/2/4/1:0                up             up       test
Se2/0.1/2/4/2:0                up             up       test
Se2/0.1/2/4/3:0                admin down     down     unused
Se2/0.1/2/5/1:0                up             up       test
Se2/0.1/2/5/2:0                up             down     path not switched
Se2/0.1/2/5/3:0                up             up       test
Se2/0.1/2/6/1:0                up             up       test
Se2/0.1/2/6/2:0                up             up       test
Se2/0.1/2/6/3:0                up             up       test
Se2/0.1/2/7/1:0                up             up       test
Se2/0.1/2/7/2:0                up             up       test
Se2/0.1/2/7/3:0                up             up       test
Se2/0.1/3/1/1:0                up             up       test
Se2/0.1/3/1/2:0                up             up       test
Se2/0.1/3/1/3:0                admin down     down     unused
Se2/0.1/3/2/1:0                up             up       test
Se2/0.1/3/2/2:0                up             up       test
Se2/0.1/3/2/3:0                up             up       test
Se2/0.1/3/3/1:0                up             up       test
Se2/0.1/3/3/2:0                up             up       test
Se2/0.1/3/3/3:0                up             up       test
Se2/0.1/3/4/1:0                down           down     unused
Se2/0.1/3/4/2:0                down           down     unused
Se2/0.1/3/4/3:0                up             up       test
Se2/0.1/3/5/1:0                up             up       test
Se2/0.1/3/5/2:0                up             up       test
Se2/0.1/3/5/3:0                up             up       test
Se2/0.1/3/6/1:0                up             up       test
Se2/0.1/3/6/2:0                up             up       test
Se2/0.1/3/6/3:0                down           down     unused
Se2/0.1/3/7/1:0                up             up       test
Se2/0.1/3/7/2:0                admin down     down     unused
Se2/0.1/3/7/3:0                up             up       test

Verifying controller configuration

You can get a comprehensive survey over the physical state of the controller, errors of SDH sections and performance counters of high- and low-order paths with the show controller sonet <brief | tabular> command.

agg-r1#sh controllers sonet 2/0 brief
SONET 2/0 is up.
  Hardware is single mode intermediate reach adapter
  H/W Version : 24.257.2.5, ROM Version : 1.2, F/W Version : 1.19.0
  FREEDM version: 2, reset 0
  Applique type is Channelized Sonet/SDH
  Description: STM1 to sdh mux
  Clock Source is Line, AUG mapping is AU4.

Medium info:
  Type: SDH, Line Coding: NRZ, Line Type: Short SM 

Regenerator Section Status:
  No alarms detected.

Multiplex Section Status:

  No alarms detected.
  No BER failure/degrade detected
  BER_SF threshold power : 3
  BER_SD threshold power : 6

Higher Order Path Status:
  Path# 1 has no defects

Lower Order Path Status:
  VC-12 1/1/1/1 has defects
    LP-UNEQ     LP-PLM
  VC-12 1/1/1/2 has no defects
  VC-12 1/1/1/3 has no defects
  VC-12 1/1/2/1 has defects
    LP-RFI
  VC-12 1/1/2/2 has no defects
  VC-12 1/1/2/3 has no defects
  .
  . (output shortened)
  .
SONET 2/0   E1   1/3/7/2 is down
  Transmitter is sending LOF Indication (RAI).
  Receiver has loss of frame.
  Framing is crc4, Clock Source is line, National bits are 0x1F.
SONET 2/0   E1   1/3/7/3 is up
  No alarms detected.
  Framing is crc4, Clock Source is line, National bits are 0x1F.

You can also examine the state of a single E1 with an extended show controller sonet command.
The syntax for the particular interface is sonet <controller>.<au-4>/<tug-3>/<tu-2>/<vc-12>

framed:
agg-r1#sh controllers sonet 2/0.1/2/5/1 brief
SONET 2/0 is up.
  Hardware is single mode intermediate reach adapter
  H/W Version : 24.257.2.5, ROM Version : 1.2, F/W Version : 1.19.0
  FREEDM version: 2, reset 0
SONET 2/0   E1   1/2/5/1 is up
  No alarms detected.
  Framing is crc4, Clock Source is line, National bits are 0x1F.
unframed:
agg-r1#sh controllers sonet 2/0.1/2/5/2 brief
SONET 2/0 is up.
  Hardware is single mode intermediate reach adapter
  H/W Version : 24.257.2.5, ROM Version : 1.2, F/W Version : 1.19.0
  FREEDM version: 2, reset 0
SONET 2/0   E1   1/2/5/2 is up
  Framing is none, Clock Source is line.

When you change the parameter brief to tabular you should see the performance data for the last 96 15min intervalls.
(This works only for framed signals)

agg-r1#sh controllers sonet 2/0.1/2/5/1 tabular
SONET 2/0 is up.
  Hardware is single mode intermediate reach adapter
  H/W Version : 24.257.2.5, ROM Version : 1.2, F/W Version : 1.19.0
  FREEDM version: 2, reset 0
SONET 2/0   E1   1/2/5/1 is up
  No alarms detected.
  Framing is crc4, Clock Source is line, National bits are 0x1F.
  INTERVAL      LCV   PCV   CSS  SEFS   LES    DM    ES   BES   SES   UAS    SS
  22:48-22:54     0     0     0     0     0     0     0     0     0     0     0
  22:33-22:48     0     0     0     0     0     0     0     0     0     0     0
  .
  . (output shortened)
  .
  02:03-02:18     0     0     0     0     0     0     0     0     0     0     0
  01:48-02:03     0     0     0     0     0     0     0     0     0     0     0
  01:33-01:48     0     0     0     0     0     0     0     0     0     0     0
  01:18-01:33     0     0     0     0     0     0     0     0     0     0     0

A nice guide for understanding SDH problems can be found here.

SDH error and alarm signals

In SDH overhead, there are a lot of OAM functionalities inter alia used for signaling errors over the transport network.
Here’s an short overview for important signals supported by Cisco.

  • Regenerator Section Errors and Alarms
    LOS regenerator section alarm indication signal
    LOF regenerator section loss of frame
    RS-TIM regenerator section trace identifier mismatch
    RS-BIP regenerator section bit errors (BIP parity error)
  • Multiplex Section Errors and Alarms
    MS-AIS multiplex section alarm indication signal
    MS-REI multiplex section path remote error indicator
    MS-RDI multiplex section path remote defect indicator
    MS-BIP multiplex section bit errors (BIP parity error)
  • Higher-order Path Errors and Alarms
    HP-UNEQ higher-order path unequipped
    HP-TIM higher-order path trace identifier mismatch
    HP-BIP higher-order path bit errors
    HP-REI higher-order path remote error indicator
    HP-RDI higher-order path remote defect indicator
    HP-PLM higher-order path payload label mismatch
  • Lower-order Path Errors and Alarms
    TU-LOP tributary unit loss of pointer
    TU-NDP tributary unit new data flag in pointer
    TU-AIS tributary unit alarm indication signal
    TU-LOM tributary unit loss of multiframe
    BIP-2/B3 lower-order path bit errors (BIP parity error)
    LP-UNEQ lower-order path unequipped
    LP-RFI lower-order path remote failure indicator
    LP-REI lower-order path remote error indicator
    LP-RDI lower-order path remote defect indicator
    LP-TIM lower-order path trace identifier mismatch
    LP-PLM lower-order path payload label mismatch
  • Line Errors and Alarms
    AIS-L line alarm indication signal
    REI-L line remote error indicator
    RDI-L line remote defect indicator
    BIP-L line bit errors (BIP parity error)

Abbreviations for PMON

To work with performance monitoring counters (PMON), you have to know the abbreviations and the values available in the different hierarchical levels.

  • Regenerator section
  • CV Code Violations Number of BIP-n parity violations
    ES Errored seconds At least one second interval during which at least one error occurred.
    SES Severely Errored seconds A one-second interval during which the BER has exceeded 1 in 10 EE-3.
    SEFS Severely Errored Framing Seconds An Severely Errored Framing Second is a second with either one or more OOF defects or a detected AIS defect.
  • Multiplex section, higher-order and lower-order (tributary) path
    CV Code Violations Number of BIP-n parity violations
    ES Errored seconds At least one second interval during which at least one error occurred.
    SES Severely Errored seconds A one-second interval during which the BER has exceeded 1 in 10 EE-3.
    AUAS Unavailable seconds The number of seconds during which the signal is alarmed or experiencing an BER exceeding 1 in 10 EE-3 for 10 consecutive seconds
  • Line

    LCV Line Code Violation Indicates the occurrence of either a Bipolar Violation (BPV) or Excessive Zeros (EXZ) error event.
    PCV Path Code Violation Indicates a frame synchronization bit error in the D4 and E1-no CRC formats, or a CRC error in the Extended Superframe (ESF) and E1-CRC formats.
    CSS Controlled slip seconds A Controlled Slip Second is a one-second interval containing one or more controlled slips
    SEFS Severely Errored Framing Seconds An Severely Errored Framing Second is a second with either one or more OOF defects or a detected AIS defect.
    LES Line Errored Seconds Line Errored Seconds (LES) is a second in which one or more Line Code Violation errors are detected.
    DM Degraded minutes A degraded minute is one in which the estimated error rate exceeds 1E-6 but does not exceed 1E-3.
    ES Errored seconds An errored second is a second in which one ore more PCV, CSS or bipolar violation (non-CRC links) is detected
    BES Bursty errored seconds A second with more than one but fewer than 320 Path Coding Violation errors, no Severely Errored Frame defects and no detected incoming AIS defects. Controlled slips are not included in this parameter.
    UAS Unavailable seconds A count of the total number of seconds on the interface. This field is calculated by counting the number of seconds that the interface is unavailable.
    SS Slip seconds Indicates the replication or deletion of the payload bits of a domestic trunk interface (DS1) frame. A slip might happen when there is a difference between the timing of a synchronous receiving terminal and the received signal.

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