Open trunking, Enabling and configuring open trunking – HP StorageWorks 2.140 Director Switch User Manual
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Director Element Manager user guide 193
determine if disabling this option (and thereby enabling RSCN transmission) will cause problems
with your HBA or storage products.
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Insistent Domain Identification (ID)—This is a parameter in the Configure Switch
Parameters dialog box, available from the Configure menu in the Element Manager. Enabling
this option sets the domain ID configured in the Preferred Domain ID box of the Configure
Switch Parameters dialog box as the active domain identification when the fabric initializes. A
static and unique domain identification is required by the Fabric Binding feature because the
feature's Fabric Membership list identifies switches by WWN and Domain ID. If a duplicate
preferred domain ID is used, then set to insistent, warnings will occur when directors and
switches are added to a Fabric Membership List.
If Fabric Binding or Enterprise Fabric Mode is enabled, this option is automatically enabled and
cannot be disabled unless these options are disabled or the switch is off line. Disabling insistent
domain ID will disable Enterprise Fabric Mode and Fabric Binding.
Open Trunking
Interswitch links (ISLs) connect ports between E_Ports on Fibre Channel switches and link these
switches into a multiswitch fabric. Multiple ISLs may be connected between the switches in the
fabric. Data from an attached end device (server or storage) flows through these ISLs to a target
end-device connected to a switch somewhere in the fabric. A data flow is data received from a
specified receive port that is destined for a port in a specified target domain (switch). The list of ISLs
that are candidates for being rerouted (to or from) is derived from the fiber shortest path first (FSPF)
algorithm.
The Open Trunking feature monitors the average data rates of all traffic flows on ISLs (from a receive
port to a target domain), and periodically adjusts routing tables to reroute data flows from
congested links to lightly loaded links and optimize bandwidth use. The objective of Open Trunking
is to make the most efficient possible use of redundant ISLs between neighboring switches, even if
these ISLs have different bandwidths.
Load balancing among the ISLs does not require user configuration, other than enabling Open
Trunking. However, you can modify default settings for congestion thresholds (per port) and the Low
BB_Credit Threshold if desired.
In particular, you do not need to manually configure ISLs into trunk groups of redundant links where
data can be off-loaded. Candidate links for rerouting flow are identified and maintained
automatically. This means that flow may be rerouted onto a link that goes to a different adjacent
switch, as long as that link is on the least-cost or shortest path to the destination domain ID.
To install and enable this option, select Configure > Features. See ”
Enabling and configuring Open Trunking
To enable Open Trunking for a specific switch and configure threshold values and event notification
options: