Provision LCAS, add/enable/remove tributaries

Procedure 11-4: Provision LCAS, add/enable/remove tributaries

Overview

Use this procedure to enable/disable LCAS or add/enable/remove tributaries to LCAS-enabled VCGs.

LCAS allows for in-service hitless addition or removal of tributary members of a Virtual Concatenation Group (VCG) to vary its bandwidth. It also allows for automatic removal and restoration of failed members.

Tributary members may be any supported tributary rate (VT1.5/VC12, STS-1/VC3, STS3c/VC4), but not a mix of rates. When a trib is added which is tardier than current members, the entire VCG is retarded to allow it to join. This is accomplished by a temporary decrease in the output payload rate, while the current members are buffered for time-alignment.

The LCAS protocol is unidirectional in that the source side controls the hitless operations. The sink side only assists by indicating whether it is ready and acknowledging completion. This means that LCAS requires a return path for signaling from the sink back to the source. Single one-way cross-connections will not provide a return path. Therefore, for each span, two-way cross-connections must be established. Then, in order to be hitless, removal operations must be sequenced between the two ends, always starting at the source side of each unidirectional link.

Important!

If only one end has LCAS enabled or the far end does not support LCAS, transmission operates normally in the non-LCAS mode. The standing condition NOTLCAS is generated when LCAS is enabled but the far end is detected as not supporting LCAS. It is cleared either when LCAS is disabled locally or the far end is detected to support LCAS.

Privilege level

You must login at least as a Privileged or General user to complete this procedure.

Before you begin

Prior to performing this procedure, refer to Before you begin and Required equipment in this chapter and you must have complete work instructions for this procedure that detail:

The shelf slots, circuit packs, ports, being provisioned.
The network configuration and termination points.
The number of tributaries being added or removed and related aids.

Steps

Determine the VCGs at each terminating end (source and sink) of the circuit being provisioned.

Adding tributaries requires that LCAS be Enabled, cross-connections established, and VCG membership enabled for each of the tributaries at the sources and sinks.

Removing tributaries requires a distinct order of removal: Disable local source tributary, disable remote source and sink tributaries, disable local sink tributary. Cross-connections for the disabled tributaries may then be removed as required.

If ...	Then ...
you are disabling LCAS, or enabling LCAS for the first time,	continue with Step 3.
you are adding tributaries to an LCAS Enabled VCG,	proceed to Step 8.
you are enabling tributaries previously added to an LCAS Enabled VCG,	proceed to Step 10.
you are removing tributaries from an LCAS Enabled VCG,	proceed to Step 14.

ENABLE/DISABLE LCAS FOR SELECTED VCGs

Determine the VCGs at each end (source and sink) of the circuit being provisioned.

Use the WaveStar^® CIT to log in to the Alcatel-Lucent 1850 TSS-5 shelves.

Reference:

Procedure 14-2: Connect personal computer (PC) and establish WaveStar^® CIT session

Select Configuration → Equipment from the System View menu, select the VCG port. Click Select.

Important!

Changing between LCAS-Enabled to LCAS-Disabled on an in-service VCG may not be hitless.

Click on the LCAS tab. Provision the LCAS parameters, as required. Or, use the ed-vcg TL1 command to provision the LCAS parameters.

LCAS parameters:

LCAS Mode: ENABLE or DISABLE (default) LCAS on the specified VCG.
Hold-Off Timer (in milliseconds): Specifies the delay time between when a tributary is detected faulty and when it is automatically removed from the VCG.
Wait-To-Restore (in seconds): Specifies the delay time between when a previously removed tributary is detected to be normal and when it is automatically returned to the VCG.

LCAS and non-LCAS interworking is supported but the change between LCAS enabled/disabled and LCAS disabled/enabled may not be hitless.

Reference:

Procedure 11-2: Provision VCG parameters

Repeat from Step 4 for each VCG port being provisioned.

END OF STEPS TO ENABLE OR DISABLE LCAS.

ADDING TRIBUTARIES

Use the WaveStar^® CIT to log in to the Alcatel-Lucent 1850 TSS-5 shelf, as required.

Reference:

Procedure 14-2: Connect personal computer (PC) and establish WaveStar^® CIT session

Make all required pass-through and add/drop cross-connections, if not already performed.

The cross-connections providing transmission between the Source and Sink VCG’s can occur at any time. Similarly the Source and Sink can be activated in any order. Only when all components are in place and enabled does the tributary member get added. Tributaries may be enabled (default) when the cross-connections are established using the WaveStar^® CIT or disabled and then enabled at a later time.

Procedure 11-3: Make cross-connections for Ethernet service

END OF STEPS FOR ADDING TRIBUTARIES.

ENABLING TRIBUTARIES

Use the WaveStar^® CIT to log in to the Alcatel-Lucent 1850 TSS-5 shelf, as required.

Select Configuration → Equipment from the System View menu, select the VCG port, then select the tributary (Trib) being provisioned. Click Select.

Or, use the ed-vcgtrib TL1 command to provision parameters.

In the Tributary provisioning screen, select Enabled for the VCG Membership for both the Input (Source) and Output Direction (sink).

When Input VCG Membership (source) (inmbs) is enabled, the VCG tributary is a member of the VCG in the source direction (towards the SONET network). When Output VCG Membership (sink) (outmbs) is enabled, the VCG tributary is a member of the VCG in the sink direction (away from the SONET network).

Repeat from Step 10 to Enable Membership for each Tributary at each VCG in each add/drop node in the configuration.

END OF STEPS FOR ENABLING TRIBUTARIES.

NOTICE

Service-disruption hazard

Service hits may occur if the proper sequence is not followed when removing tributaries from an LCAS enabled system.

REMOVING TRIBUTARIES

Use the WaveStar^® CIT to log in to the near-end Alcatel-Lucent 1850 TSS-5 shelf, as required.

Reference:

Procedure 14-2: Connect personal computer (PC) and establish WaveStar^® CIT session

Select Configuration → Equipment from the System View menu, select the VCG port, then select the tributary (Trib) being removed. Click Select.

Or, use the ed-vcgtrib TL1 command to provision parameters.

In the Tributary provisioning screen, select Disabled for the VCG Membership for the Input Direction (Source).

Use the WaveStar^® CIT to log in to the far-end Alcatel-Lucent 1850 TSS-5 shelf terminating the link.

Select Configuration → Equipment from the System View menu, select the VCG port, then select the tributary (Trib) being removed. Click Select.

Or, use the ed-vcgtrib TL1 command to provision parameters.

In the Tributary provisioning screen, select Disabled for the VCG Membership for both the Output Direction (Sink) and Input Direction (source).

Use the WaveStar^® CIT to log back in to the near-end Alcatel-Lucent 1850 TSS-5 shelf in which you started.

Select Configuration → Equipment from the System View menu, select the VCG port, then select the tributary (Trib) being removed. Click Select.

Or, use the ed-vcgtrib TL1 command to provision parameters.

In the Tributary provisioning screen, select Disabled for the VCG Membership for the Output Direction (Sink).

If required, remove all pass-through and terminating cross-connections relating to the removed tributaries.

End of steps