HP A7533A - Brocade 4Gb SAN Switch Base Administrator's Manual page 437

distance_level
vc_translation_link_init
desired_distance
5. Repeat step 4 for the remote extended ISL port. Both the local and remote extended ISL ports must be
configured to the same distance level. When the connection is initiated, the fabric will reconfigure.
The following example configures slot 1, port 1 for the LD link distance mode, enables the extended link
initialization sequence, and sets the desired distance to 50 kilometers:
switch:admin> portcfglongdistance 1/1 LD 1 50
One of the following (the numerical value representing each distance_level
is shown in parentheses):
• L0 (0) Specify L0 to configure the port to be a regular (default)
switch port.
• LE (3) Specify LE mode for distances up to 10 km.
• LD (5) Specify LD for automatic long-distance configuration. The
buffer credits for the given E_Port are automatically configured,
based on the actual link distance measured during E_Port
initialization versus the user-desired distance.
• LS (6) Specify LS mode to configure a long-distance link with a
buffer allocation based on a fixed desired distance value.
Enables the long-distance link initialization sequence. This extended link
initialization sequence is an enhanced link reset protocol, and avoids
excessive resetting of ports.
By default, this option is set to 1 (enabled). It must be set to 1 (enabled)
when configuring a trunk over extended fabrics. It must be set to 1 for a
long-distance link not configured for ISL R_RDY mode; otherwise, it must be
reset to 0.
For an LD-mode link, desired_distance is a threshold limit for link distance
to ensure buffer availability for other ports in the same port group. If the
measured distance exceeds desired_distance, desired_distance is used;
otherwise, the measured distance is used.
For an LS-mode link, desired_distance is used to calculate the buffers
required for the port.
Fabric OS 6.2 administrator guide 433