Administrator Guide

426 Fabric OS Administrator’s Guide
53-1001763-02
Trunking overview
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Re-initializing ports for trunking is required after you install the license so that the ports know that
trunking is enabled. You can enable or disable trunking for a single port or for an entire switch. For
trunking to work, individual ports or the entire switch must be set at the same speed and at the
same mode, for example, 2 Gbps, 4 Gbps, 8 Gbps, or autonegotiate. For more information on
setting port speeds, see “Trunking over long distance fabrics” on page 430.
Figure 64 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.
FIGURE 64 Distribution of traffic over ISL Trunking groups
Criteria for managing trunking connections
Following is the criteria for managing trunking connections:
• You can have up to eight ports in one trunk group to create high performance 32 Gbps ISL
trunks between switches and up to 64 Gbps if there are eight ISLs with 8 Gbps each if 8 Gbps
is supported.
• Trunk links can be 2 Gbps, 4 Gbps, or 8 Gbps depending on the Brocade platform.
• The maximum number of ports per trunk and trunks per switch depends on the Brocade
platform.
• There must be a direct connection between participating switches.
• In Fabric OS v6.1.0 and later, you can configure EX_Ports to use frame-based trunking just like
regular E_Ports. The EX_Port restrictions are the same as E_Ports. An E_Port or EX_Port trunk
can be up to eight ports wide. All the ports must be adjacent to each other using the clearly
marked groups on the front of the product See “EX_Port frame trunking configuration” on
page 474 for additional information about EX_Port trunking.
• The switch must be set to interopMode 0 for Brocade Native mode, which supports all
stand-alone Brocade switches, but provides no interoperability support. See “Interoperability
for Merged SANs” on page 297 for information and procedures related to interoperability.
• The port ISL R_RDY mode must be disabled (using the portCfgIslMode command).
Trunks operate best when the cable length of each trunked link is roughly equal to the others in the
trunk. For optimal performance, no more than 30 meters difference is recommended. Trunks are
compatible with both short wavelength (SWL) and long wavelength (LWL) fiber optic cables and
transceivers.