HP StorageWorks Fabric OS 6.1.1 administrator guide (5697-0235, December 2009)

366 Administering extended fabrics
• desired_distance is, for an LD-mode link, 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.
For an LS-mode link, desired_distance is used to calculate the buffers required for the port.
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
Table 77 lists the extended ISL modes for switches with Bloom-based ASICs. You can configure extended
ISL modes with the portCfgLongDistance command when the Extended Fabrics license is activated.
Table 77 Extended ISL modes: B-Series 2Gb Switches (Bloom and Bloom II ASICs)
Mode Buffer allocation Distance @ 1
Gbps
Distance @ 2
Gbps
Earliest
Fabric OS
release
Extended
Fabrics
license
required?
1 Gbps 2 Gbps
L0 5 (26)
1
1. For each data channel (in this case, there are 4) there are 5 credits, plus 6 extra credits.
5 (26) 10 km 5 km All No
LE 13 19 n/a 10 km 3.x, 4.x No
LD
2
2. The dynamic long-distance mode (LD) automatically configures the number of buffer credits required,
based on the actual link distance.
Auto Auto Auto
Maximum is 200 km
Auto
Maximum is 100
km
3.1.0, 4.1.0,
4.4.0, 5.x
(depending on
the model)
Yes
LS
3
3. The static long-distance mode (LS) allocates the number of buffer credits based on the user-specified
distance.
Based on
user-spec
ified
distance
Based on
user-spec
ified
distance
Based on
user-specified
distance
Maximum is 200 km
Based on
user-specified
distance
Maximum is 100
km
5.1.0 Yes