Hitless bandwidth provisioning with LCAS

Overview

Link Capacity Adjustment Scheme (LCAS) enables in-service (or non-service affecting) bandwidth increases/decreases for Ethernet links. LCAS is a two-way protocol, to function it requires a return path for signaling. It works with two-way cross connects or pairs of one-way cross connects on the span.

Description

Alcatel-Lucent 1665 DMX supports standard LCAS per ITU G.7041. Bandwidth changes to Ethernet links are done one span at a time. Without LCAS, provisioning a bandwidth change on the first span of a packet ring takes down Ethernet service around the rest of the ring until the entire ring is set to operate at the same capacity.

With LCAS, planned increases and/or decreases of bandwidth are hitless (that is, they do not affect service). As the figure below illustrates, when capacity changes to each span around the packet ring are provisioned, service is not interrupted. While the span between nodes A&B is set to 15 STS-1s, the remaining spans continue to function at 10 STS-1s.

Figure 3-9: Hitless bandwidth provisioning: 1st span

Application advantages

As the global market for communication services is in continuous flux, both advances in technology and changes in state, regional, and national economies exert various pressures on your network. Accordingly, capacity changes to your network are necessary on a regular basis.

LCAS enables you to meet the challenges of today's market without affecting service. With LCAS, you are not in danger of violating stringent Enterprise customer SLAs. You can also deploy you SONET network according to long-term growth forecasts, and get the most out of the ability to adjust Private Line and packet ring capacity within your SONET lines.