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

294 Optimizing fabric behavior
the TI zone. If failover is disabled, the TI zone traffic stops until the dedicated path is configured to be the
shortest path.
Figure 29 Dedicated path is not the shortest path
NOTE: For information about setting or displaying the FSPF cost of a path, see the linkCost and
topologyShow commands in the Fabric OS Command Reference.
Traffic Isolation over FC routers
This section describes how TI zones work with Fibre Channel routing (TI over FCR). See ”Using the FC-FC
routing service” on page 311 for information about FC routers, phantom switches, and the FC-FC Routing
Service.
Some VE_Port-based features, such as tape pipelining, require the request and corresponding response
traffic to traverse the same VE_Port tunnel across the metaSAN. To ensure that the request and response
traverse the same VE_Port tunnel, you must set up Traffic Isolation zones in the edge and backbone fabrics:
• Set up a TI zone in an edge fabric to guarantee that traffic from a specific device in that edge fabric is
routed through a particular EX_Port or VEX_Port.
• Set up a TI zone in the backbone fabric to guarantee that traffic between two devices in different fabrics
is routed through a particular ISL (VE_Ports or E_Ports) in the backbone.
This combination of TI zones in the backbone and edge fabrics ensures that the traffic between devices in
different fabrics traverses the same VE_Port tunnel in a backbone fabric. Figure 30 shows how three TI
zones form a dedicated path between devices in different edge fabrics. The backbone fabric can contain
one or more FC routers.
7
12
3
14
15
16
Domain 1 Domain 3
Domain 4
Domain 2
8
19
6
9
5
= Dedicated Path
= Ports in the TI zone