How Isl Trunking Works; Routing Of Traffic; Distribution Of Traffic Over An Isl Trunking Group - HP StorageWorks MSA 2/8 - SAN Switch User Manual

How ISL Trunking Works

The ISL Trunking software identifies and constructs trunking groups as soon as
the ISL Trunking license is activated. The ISLs and ports that participate in
trunking groups are referred to as trunking ISLs and trunking ports.
ISL Trunking makes it possible to accomplish the same fabric performance with
fewer ISLs, resulting in simplified fabric design and management, lowered cost of
ownership, increased fabric performance, and increased data availability.
Figure 1
congestion. In this example, the data available for transmission is distributed over
the four ISLs with no congestion, as it is below the total 8 Gbit/sec capacity of the
combined ISLs. In a fabric that does not have trunking capability, some paths
would be congested and other paths under utilized.
Figure 1: Distribution of traffic over an ISL Trunking group

Routing of Traffic

The same routing protocol, Fabric Shortest Path First (FSPF), is used with and
without ISL Trunking. FSPF directs traffic along the shortest path between source
and destination, based on the link cost, and makes it possible to detect link
failures, determine the shortest route for traffic, update the routing table, provide
fixed routing paths within a fabric, and maintain correct ordering of frames.
ISL Trunking Version 3.1.x/4.1.x User Guide
illustrates how trunking can result in more throughput by avoiding
Introducing ISL Trunking
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