Overview

Synchronous Digital Hierarchy (SDH) is a CCITT standard for a hierarchy of optical transmission rates. Synchronous Optical Network (SONET) is an ANSI (American National Standards Institute) standard for North America, that is largely equivalent to SDH.

Both are widely spread technologies for very high speed transmission of voice and data signals across the numerous world-wide fiber-optic networks.
SDH and SONET are point-to-point synchronous networks that use TDM multiplexing across a ring or mesh physical topology.

The main difference between both standards are the some header/pointer informations and the transmission rates.
The base transport module of SDH is the synchronous transport module with a transmission rate of 155,52mbps (STM-1), SONET uses OC-1 (~51mbs) as base module.

SDH/SONET Transmission Rates

SDH Multiplex Structure

The SDH multiplex structure shown in the picture is defined in ITU-T G.707 and describes how low order signals are multiplexed into higher multiplex levels.

KLM Values

Imagine you have a large number of E1 customer aggregated on a single port STM1. 1 port STM1 can handle 63 E1 services which we can manage it via their KLM Values.

The low order signal is transported over an SDH network, through the númerous multiplex levels, and is terminated on your channelized STM-1 card.
For configuring the customers interface on the aggregation device, you need to know in which timeslot the customers E1 resides.

–> This position is specified by the KLM values.

Here’s an overview for the KLM values of a STM-1:

For easy configuration i was using same number CEM interface in cisco as timeslot.

SAToP and CESoPSN

CEoP or SAToP defines a means to provide TDM transport across a packet or label-switched network.

• SAToP enables you to encapsulate TDM bit-streams such as T1, E1, T3, and E3 as pseudowires over packet-switched networks (PSNs).
• CESoPSN enables you to encapsulate structured (NxDS0) TDM signals as pseudowires over packet-switching networks.

SAToP Configuration In Cisco ASR900

Controller Configuration

controller MediaType 0/3/16
mode sdh
!
controller SDH 0/3/16
rate STM1
alarm-report all
secondary-admin-state in-service
clock source internal
overhead s1s0 0
aug mapping au-4
au-4 1
clock source internal

mode tug-3
tug-3 1
mode vc1x
tug-2 1 payload vc12
e1 1 cem-group 1 unframed
vc 1 overhead v5 2
e1 1 framing unframed
e1 2 cem-group 2 unframed
vc 2 overhead v5 2
e1 2 framing unframed
e1 3 cem-group 3 unframed
vc 3 overhead v5 2
e1 3 framing unframed
tug-2 2 payload vc12
e1 1 cem-group 4 unframed
vc 1 overhead v5 2
e1 1 framing unframed
e1 2 cem-group 5 unframed
vc 2 overhead v5 2
e1 2 framing unframed
e1 3 cem-group 6 unframed
vc 3 overhead v5 2
e1 3 framing unframed

L2VPN Configuration

interface CEM0/3/16
no ip address
cem 1
xconnect ip_endpoint 1 encapsulation mpls
!
cem 2
xconnect ip_endpoint 2 encapsulation mpls
!
cem 3
xconnect ip_endpoint 3 encapsulation mpls
!
cem 4
xconnect ip_endpoint 4 encapsulation mpls
!
cem 5
xconnect ip_endpoint 5 encapsulation mpls
!
cem 6
xconnect ip_endpoint 6 encapsulation mpls
!
cem 7
xconnect ip_endpoint 7 encapsulation mpls
!
cem 8
xconnect ip_endpoint 8 encapsulation mpls
!
cem 9
xconnect ip_endpoint 9 encapsulation mpls
!
cem 10
xconnect ip_endpoint 10 encapsulation mpls

CESoPSN Configuration

Controller Configuration

controller SDH 0/7/16
rate STM1
no ais-shut
alarm-report all
secondary-admin-state in-service
clock source internal
overhead s1s0 0
aug mapping au-4
au-4 1
clock source internal

mode tug-3
tug-3 1
mode vc1x
tug-2 1 payload vc12
e1 1 cem-group 1 timeslots 1-31
vc 1 overhead v5 2
e1 2 cem-group 2 timeslots 1-31
vc 2 overhead v5 2
e1 3 cem-group 3 timeslots 1-31
vc 3 overhead v5 2
tug-2 2 payload vc12
e1 1 cem-group 4 timeslots 1-31
vc 1 overhead v5 2
e1 2 cem-group 5 timeslots 1-31
vc 2 overhead v5 2
e1 3 cem-group 6 timeslots 1-31
vc 3 overhead v5 2
tug-2 3 payload vc12
e1 1 cem-group 7 timeslots 1-31
vc 1 overhead v5 2
e1 2 cem-group 8 timeslots 1-31
vc 2 overhead v5 2
e1 3 cem-group 9 timeslots 1-31
vc 3 overhead v5 2
tug-2 4 payload vc12
e1 1 cem-group 10 timeslots 1-31
vc 1 overhead v5 2
e1 2 cem-group 11 timeslots 1-31
vc 2 overhead v5 2
e1 3 cem-group 12 timeslots 1-31
vc 3 overhead v5 2

L2VPN Configuration

interface CEM0/7/16
no ip address
cem 1
xconnect ip_endpoint 1 encapsulation mpls
!
cem 2
xconnect ip_endpoint 2 encapsulation mpls
!
cem 3
xconnect ip_endpoint 3 encapsulation mpls
!
cem 4
xconnect ip_endpoint 4 encapsulation mpls
!
cem 5
xconnect ip_endpoint 5 encapsulation mpls
!
cem 6
xconnect ip_endpoint 6 encapsulation mpls
!
cem 7
xconnect ip_endpoint 7 encapsulation mpls
!
cem 8
xconnect ip_endpoint 8 encapsulation mpls
!
cem 9
xconnect ip_endpoint 9 encapsulation mpls
!
cem 10
xconnect ip_endpoint 10 encapsulation mpls

Verify

 

• show controller SDH x/x/x — shows the status of the SDH controller facing endpoints
• show xconnect all — shows a summary of all pseudowire status
• show cem circuit — shows a summary of all CEM status
• show cem circuit detail — shows detailed information/statistics for all CEM groups
• show cem circuit interface CEM#/# — shows detailed info for CEM#/#
• show mpls l2transport vc [vcid] detail — shows detailed information regarding PW status

References :

• http://www.net-gyver.com/?p=809
• https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/cether/configuration/xe-3s/asr903/ce-xe-3s-asr903-book/ce-pse.html