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

Fabric OS 6.1.x administrator guide 317
Fibre Channel fabrics require that all ports be identified by a unique PID. In a single fabric, FC protocol
guarantees that Domain IDs are unique, and so a PID formed by a Domain ID and area ID is unique within
a fabric. However, the Domain IDs and PIDs in one fabric may be duplicated within another fabric, just as
IP addresses are unique to one private network are likely to be duplicated within another private network.
In an IP network, a network router can maintain network address translation (NAT) tables to replace private
network addresses with public addresses when a packet is routed out of the private network, and to
replace public addresses with private addresses when a packet is routed from the public network to the
private network. The Fibre Channel routing equivalent to this IP-NAT is the Fibre Channel network address
translation (FC-NAT). Using FC-NAT, the proxy devices in a fabric can have different PIDs than the real
devices that they represent, allowing the proxy devices to have appropriate PIDs for the address space of
their corresponding fabric.
All EX_Ports connected to the same edge fabric from one physical FC router present a single front phantom
domain and one additional translate (xlate) phantom domain for each edge fabric accessed through it. All
EX_Ports and VEX_Ports connected to an edge fabric use the same xlate Domain ID number for an
imported edge fabric; this value persists across switch reboots and fabric reconfigurations. Xlate domains
are presented as being connected topologically behind one or more front domains; each FC-Router
presents one front domain to the edge fabric. This allows redundant paths in remote fabrics to present
themselves as redundant paths to proxy devices in an edge fabric.
Phantom domains are like logical switches that appear to be connected to an edge fabric through the front
domains that are presented by EX_Ports and VEX_Ports. The combination of front domains and xlate
domains allows routing around path failures, including path failures through the routers. The multiple paths
to a xlate domain provide additional bandwidth and redundancy.
There are some differences in how the xlate domain is presented in the BB. The BB xlate domains are
topologically connected to FC routers and participate in FC-Protocol in the BB. Front domains are not
needed in the BB. As in the case of a xlate domain in edge fabric, BB xlate domains provide additional
bandwidth and redundancy by being able to present themselves as being connected to single or multiple
FC routers with each FC router capable of connecting multiple IFLs to edge fabrics.
Setting up the FC-FC routing service
To set up the FC-FC Routing Service, perform the following tasks:
1. Verify that you have the proper setup for FC-FC routing (see ”Verifying the setup for FC-FC routing” on
page 317).
2. Assign backbone fabric IDs (see ”Assigning backbone fabric IDs” on page 319).
3. Configure FCIP tunnels, if you are connecting Fibre Channel SANs over IP-based networks (see
”Configuring FCIP tunnels” on page 320).
4. Configure IFLs for edge and backbone fabric connection (see ”Configuring an interfabric link” on
page 320) (see ”Configuring an interfabric link” on page 320).
5. Modify port cost for EX_Ports, if you want to change from the default settings (see ”Configuring the FC
router port cost” on page 324).
6. Configure trunking on EX_Ports that are connected to the same edge fabric (see ”Configuring EX_Port
frame trunking (optional)” on page 327).
7. Configure LSAN zones to enable communication between devices in different fabrics (see ”Configuring
LSANs and zoning” on page 329).
See ”Configuring Directors” on page 225 for more information about configuration options for Directors.
Verifying the setup for FC-FC routing
Before configuring a fabric to connect to another fabric, you must perform the following verification checks
on the FC router: