Brocade Fabric OS Administrators Guide (Supporting Fabric OS v7.3.0) - Manual (Page 516)

ISL trunking over long-distance fabrics
In long-distance fabrics, if a port speed is set to autonegotiate, then the maximum speed, which is 16
Gbps, is assumed for reserving buffers for the port. If the port is running at only 2 Gbps, this wastes
buffers. For long-distance ports, you should specify the port speed instead of setting it to
autonegotiate.
In addition to the criteria listed in Supported configurations for trunking on page 511, observe the
following criteria for trunking over long-distance fabrics:
• Trunking over long-distance fabrics is supported only on switches running Fabric OS v6.1.0 and
later.
• Extended Fabrics and Trunking licenses are required on all participating switches.
• When configuring long distance, you must configure the portCfgLongDistance --
vc_translation_link_init parameter to be the same on all ports in a long-distance fabric.
For additional information on configuring long distance, refer to Configuring an extended ISL on page
529.
Table 90 summarizes support for trunking over long distance for the Brocade DCX and DCX 8510
Backbones and supported blades.
Trunking over long distance for the Brocade Backbones and blades TABLE 90
Long-distance mode Distance Number of 2-Gbps ports Number of 4-Gbps ports
LE 10 km 48 (six 8-port trunks) 48 (six 8-port trunks)
L0 Normal See note below 48 (six 8-port trunks)
LD 200 km 4 (one 2-port trunk per switch) 0
LD 250 km 4 (one 2-port trunk per switch) 0
LD 500 km 0 0
LS Static See note below
NOTE
The L0 mode supports up to 5 km at 2 Gbps, up to 2 km at 4 Gbps, and up to 1 km at 8 Gbps.The
distance for the LS mode is static. You can specify any distance greater than 10 km.
The distance supported depends on the available buffers, the number of back-end ports, and the
number of ports that are offline. For more information on setting port speeds, refer to
Performing
Advanced Configuration Tasks on page 65.
EX_Port trunking
You can configure EX_Ports to use trunking just as you do regular E_Ports. EX_Port trunking support
is designed to provide the best utilization and balance of frames transmitted on each link between the
FC router and the edge fabric. You should trunk all ports connected to the same edge fabrics.
ISL trunking over long-distance fabrics
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