Cisco Systems 15454 11.11 BLSR STS and VT Squelch Tables

11-22

Cisco ONS 15454 Reference Manual, R7.0

78-17191-01

Chapter 11 Circuits and Tunnels

11.11 11.11 BLSR STS and VT Squelch Tables

11.11 BLSR STS and VT Squelch Tables

ONS 15454 nodes display STS and VT squelch tables depending on the type of circuits created. For

example, if a fiber cut occurs, the BLSR squelch tables show STSs or VTs that will be squelched for

every isolated node. Squelching replaces traffic by inserting the appropriate alarm indication signal path

(AIS-P) and prevents traffic misconnections. For an STS with a VT-access check mark, the AIS-P will

be removed after 100 ms. To view the squelch tables, refer to the “Manage Circuits” chapter in the

Cisco ONS 15454 Procedure Guide for detailed instructions. For more information about BLSR

squelching, refer to Telcordia GR-1230.

BLSR STS squelch tables show STSs that will be squelched for every isolated node.

The BLSR Squelch Table window displays the following information:

• STS Number—Shows the BLSR STS numbers. For two-fiber BLSRs, the number of STSs is half

the BLSR OC-N, for example, an OC-48 BLSR squelch table will show 24 STSs. For four-fiber

BLSRs, the number of STSs in the table is the same as the BLSR OC-N.

• West Source—If traffic is received by the node on its west span, the BLSR node ID of the source

appears. (To view the BLSR node IDs for all nodes in the ring, click the Ring Map button.)

• West VT (from the West Source) — A check mark indicates that the STS carries incoming VT

traffic. The traffic source is coming from the west side.

• West VT (from the West Destination) — A check mark indicates that the STS carries outgoing VT

traffic. The traffic is dropped on the west side.

• West Dest—If traffic is sent on the node’s west span, the BLSR node ID of the destination appears.

• East Source—If traffic is received by the node on its east span, the BLSR node ID of the source

appears.

• East VT — (from the East Source) - A check mark indicates that the STS carries incoming VT

traffic. The traffic source is coming from the east side.

• East VT — (from the East Destination) - A check mark indicate that the STS carries outgoing VT

traffic. The traffic is dropped on the east side.

• East Dest—If traffic is sent on the node’s east span, the BLSR node ID of the destination appears.

Note BLSR squelching is performed on STSs that carry STS circuits only. Squelch table entries will not

appear for STSs carrying VT circuits or Ethernet circuits to or from E-Series Ethernet cards provisioned

in a multicard Ethergroup.

BLSR VT squelch tables only appear on the node dropping VTs from a BLSR and are used to perform

VT-level squelching when a node is isolated. VT squelching is supported on the ONS 15454 and the

ONS 15327 platforms. The ONS 15600 platform does not support VT squelching; however, when an

ONS 15454 and an ONS 15600 are in the same network, the ONS 15600 node allows the ONS 15454

node to carry VT circuits in a VT tunnel. The ONS 15600 performs 100-ms STS-level squelching for

each VT-access STS at the switching node in case of a node failure.