Brocade Access Gateway Admin Guide v6.1.0 (53-1000605-02, June 2008)

22 Access Gateway Administrator’s Guide

53-1000605-02

Access Gateway N_Port trunking

On switches running in Access Gateway mode, the masterless trunking feature trunks N_Ports

because only the external port or the N_Port can connect to a switch in AG mode. After you map or

assign F_Ports to an N_Port, the N_Port distributes frames across a set of available path links on

the switch in AG mode to an adjacent edge switch. To use Access Gateway masterless trunking, all

trunking must be configured on the edge switch. Following are the advantages of Access Gateway

N_Port trunking:

• When one or more N_Ports in a trunk group goes offline, there is no change in the PID for the

F_Port(s) that were mapped to the N_Port(s) as long as at least one N_Port in the trunk group

is active. This provides for a transparent failover and failback within the trunk group.

• N_Port links are more efficient because of the trunking algorithm implemented in the

switching ASICs that distributes the I/O more evenly across the N_Ports.

• Trunk groups cannot span across multiple N_Port groups within a switch in AG mode.

• Multiple trunk groups are allowed within the same N_Port group.

NOTE

On the edge switch, this feature is called F_Port trunking or masterless F_Port trunking.

Because you must configure the trunking on the edge switch, F_Port trunking, provides a Trunk

group between a switch (N_Port) in Access Gateway (AG) mode and Condor-based platforms. This

feature keeps F_Port(s) from becoming disabled in the case where they are mapped to an N_Port

on a switch in Access Gateway mode. With F_Port trunking, any link within a trunk can go off line or

become disabled, but the trunk remains fully functional and there are no re-configuration

requirements.

F_Port trunking prevents reassignments of the Port ID (also referred to as the Address Identifier as

described in Table 5 on page 25) when F_Ports go offline and it increases F_Port bandwidth.

Access Gateway N_Port trunking interoperates between Access Gateway (AG), 2 Gbps, 4 Gbps, and

8 Gbps-based platforms. This feature does not work on M-EOS or third party switches.

You must install the Brocade ISL license on the switch, which must be running Fabric OS 6.1.0 or

later. All switches that you connect to AG must be included in a port group; otherwise, switches

outside of a port group cannot connect to AG. For more information on Port Groups, see “Port

Grouping policy” on page 17.

NOTE

If a switch already has an ISL Trunking license, no new licenses is required to use it on AG N_Port

masterless trunking; Also, after a trunking license is installed on a switch in AG mode and you

change the switch to standard mode, you can keep the same license.

To implement N_Port masterless trunking, you must first configure an F_Port Trunk group and

statically assign an Area_ID within the trunk group. Assigning a Trunk Area (TA) to a port or trunk

group enables F_Port masterless trunking on that port or trunk group. When a TA is assigned to a

port or trunk group, the ports will immediately acquire the TA as the area of its process IDs (PID).

And when a TA is removed from a port or trunk group, the ports reverts to the default area as its

PID.