HP Brocade 4Gb SAN Switch for HP BladeSystem p-Class - Manual (Page 108)

108 Administering extended fabrics
Fabric considerations
Consider these items that affect the fabric when you configure extended ISLs:
• The extended link configuration mode, L2 can reach 100 km at a speed of 2Gbps between HP Fabric
OS v4.x switches. However, it only supports a distance of up to 60 km if the link is established
between HP Fabric OS v3.x and 4.x switches.
• The standard-distance and long-distance ISL modes cannot be enabled at the same time.
• Balance the number of long-distance ISL connections and core-to-edge ISL connections within a switch.
Configuring long-distance ISLs between core and edge switches is possible, but is not a practice
recommended by HP.
• Starting with Fabric OS v4.4.0, VC translation link initialization (an option of the
portcfglongdistance
command) is enabled by default for long-distance links. For previous
Fabric OS versions that support this option, it was disabled by default. To avoid inconsistency in the
fabric, make sure that this value is enabled on both ends of the link. To connect to switches running
Fabric OS versions earlier than v4.0.2 and v3.0.2c, make sure that VC translation link initialization is
disabled, because these versions do not support it.
Choosing an extended ISL mode
Table 15 lists the extended ISL modes, which you can configure with the
portcfglongdistance
command when the Extended Fabrics license is activated. For standard ISL modes that do not require
Extended Fabrics licensing, see Table 4 on page 31.
Table 15 Extended ISL modes
Mode Description Maximum ISL distance (km) Earliest Fabric OS
release
L0.5 Level 0.5 static mode
(designated LM when listed
with the
portcfgshow
command).
25 km at 1, 2, or 4 Gbps v3.1.0, v4.1.0
L1 Level 1 static mode. 50 km at 1, 2, or 4 Gbps All
L2 Level 2 static mode. 64 or 100 km at 1, 2, or 4
Gbps 1
All
LD Dynamic mode uses
automatic distance detection
for a user-specified distance.
• SAN Switch 4/32:
• 500 km at 1 Gbps
• 250 km at 2 Gbps
• 100 km at 4 Gbps
• Other supported models 1 :
• 100 or 200 km at 1
Gbps
• 64 or 100 km at 2
Gbps
1. The maximum ISL distance depends on the version of HP StorageWorks ASIC installed in the switch.
v3.1.0, v4.1.0, v 4.4.0
(depending on the
model)