Technical data

Fabric OS Administrator’s Guide 12-1
Publication Number: 53-0000518-09
Chapter
12
Administering ISL Trunking
This chapter contains procedures for using the Brocade ISL Trunking licensed feature, which optimizes
the use of bandwidth by allowing a group of interswitch links to merge into a single logical link.
Overview
Brocade ISL Trunking reduces or eliminates situations that require static traffic routes and individual
ISL management to achieve optimal performance. Trunking optimizes fabric performance by
distributing traffic across the shared bandwidth of all the interswitch links in a trunking group, allowing
traffic to flow through any available link in a group rather than restricting it to a specific, potentially
congested link. The use of trunking results in simplified fabric design and management, lowered cost of
ownership, and increased data availability.
To use trunking, you must first install the Brocade ISL Trunking license. For details on obtaining and
installing licensed features, refer to “Maintaining Licensed Features” on page 2-8. Trunking is enabled
automatically when the ISL Trunking license is activated and ports are reinitialized (after installing the
license, you enter the switchDisable and switchEnable commands), and trunks are easily managed
using either Fabric OS CLI commands or Web Tools. You can enable and disable trunking and set trunk
port speeds (for example, 2 Gig/sec, 4 Gig/sec, or autonegotiate) for entire switches or for individual
ports.
Trunks distribute traffic dynamically and in order at the frame level, achieving greater performance with
fewer interswitch links.
Trunks are compatible with both short wavelength (SWL) and long wavelength (LWL) fiber optic
cables and transceivers.
Figure 12-1 illustrates how trunking can result in more throughput by distributing data over four ISLs
with no congestion. In a fabric that does not have trunking capability, some paths would be congested
and other paths underutilized.