Consider a deployment scenario with the TDM circuits from a base transceiver station is connected to an access router and must be transported to the base station controller through an aggregation router over an MPLS network through pseudowire.

During aggregation from transceiver to controller, the TDM circuits protect the data by using smart SFPs. For the E1 lines coming from transceiver, you must use TPoP SFPs and for the STM-1 lines coming from transceiver or controller, you must use CSoP SFPs.

You can monitor the alarms and performances on TPoP and CSoP smart SFPs.

Also consider a case, with Automatic Protection Switching (APS) protection being enabled on the controller, then the protect link coming from a single node or from multiple nodes with standby pseudowire is supported in the MPLS core.

enable
configure terminal 
    controller e1  0/0/0/7
    vlan 100 ecid 1
end

Router# show controller e1 0/0/0/7
Controller State: Up
Transport Admin State: In Service
Framing: Unframed
Linecoding: High Density Bipolar Order 3
Loopback: None
Clock: Adaptive Clock Recovery (ACR)
Clock State: Locked
VLAN ID: 100
ecid:1 

controller STM1 0/0/0/18
 aug-mapping au4 au-4 1
  mode tug3
   tug-3 1
    mode tug2
     tug-2 1 payload vc12
      vc12 1 mapping e1

/*Configure STM1-ch E1 */

Router# show controller STM1 0/0/0/18
Port STM 10/0/0/18

Status:
Primary State: Up
Configured Sec admin State: Normal
Inherited Sec admin State: Normal
Derived State: In Service
performance_monitoring_enabled
Loopback: None

Config terminal
    controller E1 0/0/0/18/1/1/1/1
    vlan 200 ecid 1

Router# show controller e1 0/0/0/18/1/1/1/1
Controller State: Up
Transport Admin State: In Service
Framing: Unframed
Linecoding: None
Loopback: None
Clock: Internal

VLAN ID: 200
ecid:1 

The TDM circuits flows through the VPWS with smart SFP packetizing the incoming TDM frames. Packetizing happens with the following process:

• All frames from the TDM lines are channelized until E1 and then packetized.

• The packetization is done by adding:

  • RTP header – For DCR clocking support

  • VLAN header – For uniquely identifying the E1 channel

  • ENET header – The Ethernet DMAC and SMAC

  • CW – control word for communicating the sequence number, faults in the access side

  • Payload – the incoming TDM frames are chopped into 193Bytes frames and added into the payload.

  • The packets mentioned previously sent to the NPU.

• The E1 channel is mapped into a sub-interface (with specific VLAN).

• The packets received into the NPU with that specific VLAN number go through the VPWS logic and gets pseudowired (xconnected) with the configuration in a specific sub-interface.

• QOS configured under the sub-interface gets applied to this PW.

The Multi Router Automatic Protection Switching (MR-APS) integration with hot standby pseudowire (HSPW) feature is a protection mechanism for SDH to switch to another circuit during failure.

Consider a deployment scenario with the MR-APS circuits from a base transceiver station is connected to access router and must be transported to the base station controller through an aggregation router over an MPLS network through pseudowire. When the pseudowire reaches the router with MR-APS, data is depacketized on the smart SFP and the raw TDM frames are sent towards the base station controller. The controller is connected to routers via two links, one as working link from router-A and other as protect link towards the router-B.

Configuring Xconnect on Sub-Interface

To configure E1 port based on the VLAN ID, create sub-interface Gigabit Ethernet port.

Note	The propagate-tdm-alarm command enables the forwarding of port level alarms to Gigabit Ethernet port in which Smart SFP resides.

Config terminal
controller STM1 0/0/0/0
   propagate-tdm-alarm
!
interface GigabitEthernet0/0/0/18.200 l2transport
 encapsulation dot1q 200
!

 
interface GigabitEthernet0/0/0/7.100 l2transport
 encapsulation dot1q 100

l2vpn
 pw-class tdm_pw
  encapsulation mpls
  !
 !
 xconnect group tdm_csop
  p2p pw200
   interface GigabitEthernet0/0/0/18.200
   neighbor ipv4 2.2.2.2 pw-id 200
    pw-class tdm_pw
   !
  !
 !
 xconnect group tdm_tpop
  p2p pw100
   interface GigabitEthernet0/0/0/7.100
   neighbor ipv4 2.2.2.2 pw-id 100
    pw-class tdm_pw
   !
  !
 !
!

For more information on the standby pseudowire, see Configure Pseudowire Redundancy in chapter Configure Point-to-Point Layer 2 Services of the L2VPN and Ethernet Services Configuration Guide.

Warning

If MR-APS is configured on the SFP, then remove MR-APS configuration before you remove the SFP from the port.

• CEM interface configuration isn’t supported.

• The following default attributes are available only under CEM interface configuration. But you can't configure these attributes, as the configuration CLIs aren’t supported.

  • dummy mode

  • dummy pattern

  • idle pattern

• E1 emulation is supported only on Ethernet pseudowire (VPWS).

• CSoP doesn’t support E1-AIS alarm.

• No support to Single Router–Automatic Protection Switching (SR-APS)

• CLI configuration for the E1 controller on a VLAN needs to be mapped to an Ethernet sub-interface (by configuring same VLAN dot1q under the sub-interface). Any xconnect, also must be configured with this ethernet sub-interface.

• Multi Router-Automatic Protection Switching (MR-APS) is supported only by using the VLAN PW.

• Ensure that you have more than one MPLS paths, in core to convergence during core failure scenario.

• Only 8 smart SFPs are supported per router.

• ACR clocking is not supported in TPoP and CSoP unframed SFPs. Only framed to framed connection is supported, so not supported on framed to unframed connections.

• STM1 CSoP:

  • E1 Level shutdown is not supported.

  • Controller shutdown won’t inject AIS but injects only LOS towards CE.

  • Bit error rate test (BERT) can be run only on one E1 channelized controller.

• CSoP and TPoP:

  • 25G ports are not supported.

  • Bit error rate is not supported.

• SF or SD threshold is not supported.

• Only 16-byte J0 is supported.

• BERT is not supported in unframed SFP.

• Loopback is supported only on, one of the 63 channels of CSoP SFP.

• Configuration with same ECID for CSoP E1s is not supported. ECID must be unique for each E1 under CSoP.

• The show alarm conditions command is not supported in Release 7.5.1.

• High convergence of 100ms is observed for MR-APS for LOS based switchover (for CSoP E1s).

• With smart SFP, high convergence of 4-6 minutes is observed in MR-APS for router reload based switchover.

• CSoP loopback on framed STM1-ch E1 doesn’t work over reload warm command with smart SFP. Applicable only in Release 7.5.1.

• FPD upgrade for smart SFP is supported only from Release 7.8.1.

• LCV counter updates are not supported for smart SFP.