User Manual

OpenSM – Subnet ManagerRev 2.2-1.0.1
Mellanox Technologies
190
8.5.8 Routing Chains
As of today, as it is impossible to configure each part of the fabric to be routed using different
routing engines, a fabric can be routed using only one routing engine at a time. The routing
chains feature is offering a solution that enables one to configure different parts of the fabric and
define a different routing engine to route each of them. The routings are done in a sequence
(hence the name "chains") and any node in the fabric that is configured in more than one part is
left with the routing updated by the last routing engine it was a part of.
8.5.8.1 Configuring Routing Chains
The configuration for the routing chains feature consists of the following steps:
1. Define the port groups.
2. Define topologies based on previously defined port groups.
3. Define configuration files for each routing engine.
4. Define routing engine chains over previously defined topologies and configuration files.
8.5.8.1.1 Defining Port Groups
The basic idea behind the port groups is the ability to divide the fabric into sub-groups and give
each group an identifier that can be used to relate to all nodes in this group. The port groups is a
separate feature from the routing chains, but is a mandatory prerequisite for it. In addition, it is
used to define the participants in each of the routing algorithms.
Defining a Port Group Policy File
In order to define a port group policy file, set the parameter 'pgrp_policy_file' in the opensm con-
figuration file.
pgrp_policy_file /etc/opensm/conf/port_groups_policy_file
Configuring a Port Group Policy
The port groups policy file details the port groups in the fabric. The policy file should be com-
posed of one or more paragraphs that define a group. Each paragraph should begin with the line
'port-group' and end with the line 'end-port-group'.
For example:
port-group
…port group qualifiers…
end-port-group