Brocade Fabric OS Administrators Guide (Supporting Fabric OS v7.3.0) - Manual (Page 512)

High Availability support for trunking
Trunking is a High Availability (HA) supported feature. The HA protocol for trunking is as follows:
• If trunking is disabled prior to the HA failover, it remains disabled after the HA failover.
• If trunking is enabled prior to the HA failover, it remains enabled after the HA failover.
Requirements for trunk groups
The following requirements apply to all types of trunking:
• All of the ports in a trunk group must belong to the same port group.
• All of the ports in a trunk group must meet the following conditions:
‐ They must be running at the same speed.
‐ They must be configured for the same distance.
‐ They must have the same encryption, compression, QoS, and FEC settings.
• Trunk groups must be between Brocade switches (or Brocade adapters in the case of F_Port
trunking). Brocade trunking is proprietary and is not supported on M-EOS or third-party switches.
• There must be a direct connection between participating switches.
• Trunking cannot be done if ports are in ISL R_RDY mode. (You can disable this mode by using the
portCfgIslMode command.)
• Trunking is supported only on FC ports. Virtual FC ports (VE_Ports or VEX_Ports) do not support
trunking.
Recommendations for trunk groups
To identify the most useful trunk groups, consider the following recommendations along with the
standard guidelines for SAN design:
• Evaluate the traffic patterns within the fabric.
• Place trunking-capable switches adjacent to each other.
This maximizes the number of trunk groups that can form. If you are using a core and edge topology,
place trunking-capable switches at the core of the fabric and any switches that are not trunking-
capable at the edge of the fabric.
• When connecting two switches with two or more ISLs, ensure that all trunking requirements are met
to allow a trunk group to form.
• Determine the optimal number of trunk groups between each set of linked switches, depending on
traffic patterns and port availability.
The goal is to avoid traffic congestion without unnecessarily using ports that could be used to attach
other switches or devices. Consider these points:
• Each physical ISL uses two ports that could otherwise be used to attach node devices or other
switches.
• Trunk groups can be used to resolve ISL oversubscription if the total capability of the trunk group is
not exceeded.
• Consider how the addition of a new path will affect existing traffic patterns:
High Availability support for trunking
512 Fabric OS Administrators Guide
53-1003130-01