Standard Trunking Criteria; Fabric Considerations For Isl Trunking - HP A7533A - Brocade 4Gb SAN Switch Base Administrator's Manual

B-Series Multi-Protocol Router Blade, and the HP StorageWorks DC04 SAN Director Switch using HP
StorageWorks SAN Director 16 Port 8Gb FC blade, HP StorageWorks SAN Director 32 Port 8Gb FC
blade, HP StorageWorks SAN Director 48 Port 8Gb FC blade, and the B-Series Multi-Protocol Router Blade
support these advanced features:
• Up to eight ports in one trunk group to create high performance 32 Gb/s ISL trunks between switches
and up to 64 Gb/s if there are eight ISLs with 8 Gb/s each, and 8 Gb/s is supported.
• ISL Trunking over longer distances than other platforms
• Dynamic trunk master reassignment if a trunk master is disabled (on other platforms, all ports on a trunk
must be disabled temporarily to reassign a master)
• 4 Gb/s trunk links
• 8 Gb/s trunk links where supported
The maximum number of ports per trunk and trunks per switch depends on the HP StorageWorks platform.
NOTE: The HP StorageWorks SAN Director 6 Port 10Gb FC blade does not support trunking.

Standard trunking criteria

Observe the following criteria for standard distance trunking:
• There must be a direct connection between participating switches.
• Trunk ports must reside in the same port group.
• Trunk ports must run at the same speed (either 2 Gb/s, 4 Gb/s, or 8 Gb/s).
• Trunk ports must be set to the same ISL mode (L0 is the default). For details on extended ISL modes, see
Chapter 19,
• If the switch is in Access Gateway mode, the trunk ports must be F_Ports.
In Fabric OS 5.2.0 and later, you can configure EX_Ports to use frame-based trunking just like regular
E_Ports. EX_Port frame-based trunking has a master trunk link. If the master link goes down, the entire
trunk re-forms and is taken offline for a short period of time. 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.
• The switch must be set to interopMode 0 for Brocade Native mode, which supports all stand-alone
B-Series fabrics, but provides no interoperability support. See Chapter 12,
SANs" on page 291 for information and procedures related to interoperability modes.
• The port ISL mode must be disabled (using the portCfgIslMode command).

Fabric considerations for ISL trunking

To identify the most useful trunking 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 trunking 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 trunking group to form.
• Determine the optimal number of trunking 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.
436 Administering ISL trunking
"Administering extended fabrics" on page 423.
"Interoperability for merged