Table of Contents
Advertisement
11.18.3 Link Capacity Adjustment
Table 11-16
Type of circuit
CCAT
HO VCAT
HO LCAS
LO VCAT
LO LCAS
1. The calculated number for HO LCAS includes all the inherent delays of the protocol. Also the CE-100-T numbers are for a
Note
11.18.3 Link Capacity Adjustment
The CE-100T-8 card supports the link capacity adjustment scheme (LCAS), which is a signaling
protocol that allows dynamic bandwidth adjustment of VCAT circuits. When a member fails, a brief
traffic hit occurs. LCAS temporarily removes the failed member from the VCAT circuit for the duration
of the failure, leaving the remaining members to carry the traffic. When the failure clears, the member
circuit is automatically added back into the VCAT circuit without affecting traffic. You can select LCAS
during VCAT circuit creation.
Although LCAS operations are errorless, a SONET error can affect one or more VCAT members. If this
Note
occurs, the VCAT Group Degraded (VCG-DEG) alarm is raised. For information on clearing this alarm,
refer to the Cisco ONS 15454 Troubleshooting Guide.
Instead of LCAS, the FC_MR-4 (enhanced mode), CE-1000-4 card, and ML-Series cards support
software LCAS (SW-LCAS). SW-LCAS is a limited form of LCAS that allows the VCAT circuit to adapt
to member failures and keep traffic flowing at a reduced bandwidth. SW-LCAS uses legacy SONET
failure indicators like AIS-P and remote defect indication, path (RDI-P) to detect member failure.
SW-LCAS removes the failed member from the VCAT circuit, leaving the remaining members to carry
the traffic. When the failure clears, the member circuit is automatically added back into the VCAT
circuit. For ML-Series cards, SW-LCAS allows circuit pairing over two-fiber BLSRs. With circuit
pairing, a VCAT circuit is set up between two ML-Series cards: one is a protected circuit (line
protection) and the other is a PCA circuit. For four-fiber BLSRs, member protection cannot be mixed.
You select SW-LCAS during VCAT circuit creation. The FC_MR-4 (line rate mode) does not support
SW-LCAS.
In addition, you can create non-LCAS VCAT circuits, which do not use LCAS or SW-LCAS. While
LCAS and SW-LCAS member cross-connects can be in different service states, all In Group non-LCAS
members must have cross-connects in the same service state. A non-LCAS circuit can mix Out of Group
and In Group members, as long as the In Group members are in the same service state. Non-LCAS
members do not support the OOS-MA,OOG service state; to put a non-LCAS member in the Out
of Group VCAT state, use the OOS-MA,DSBLD administrative state.
Cisco ONS 15454 Reference Manual, R8.5
11-36
Switch Times
1
group size of only three members.
The switch time values shown in
differential delay for CE100T-8 is 122ms. This differential delay is added to the switch time to
get the maximum time.
For CE100T-8 in ms
60
90
90
202
202
Table 11-16
does not include differential delay. The maximum
Chapter 11
Circuits and Tunnels
78-18106-01
Advertisement
Table of Contents
