.Part 1 Architecture HP SAN Design Reference Guide 785351-001

Simple fabric services
SNS provides a mapping between device names and their addresses in a fabric. To ensure that
the mapping is up-to-date, every switch in the fabric implements SNS.
Coordinating fabric services
Each fabric maintains a unique set of fabric services. When two fabrics are connected, their two
sets of services merge to form a single set.
As fabrics grow, coordinating the fabric services across switches, hosts, and storage devices
becomes more challenging. It is difficult to match the fabric service requirements for very small,
inexpensive switches with those for large, high-end switches. Without routing, fabric scaling is
limited by the ability of the smallest fabric switch to participate in the distributed fabric services
system.
Scaling by routing
Increasing fabric port count and switch count limits meets most customer scaling requirements.
Demand for higher port counts and connectivity between devices in different fabrics, Virtual Fabrics,
or VSANs requires Fibre Channel routing.
Routing improves scaling by connecting independent fabrics, Virtual Fabrics, or VSANs, each
potentially at its full capacity. Connectivity between fabrics, Virtual Fabrics, or VSANs allows
sharing of resources, reducing unnecessary redundancy in the routed network.
You can route between fabrics without affecting the total switch and port count limits. However,
the routed network is not the same as a single large fabric, Virtual Fabric, or VSAN. Only selected
devices in each fabric, specified by a routing table, can communicate with devices in other fabrics.
For example, using a router, you can connect three 1,200-port fabrics to construct a 3,600-port
Meta SAN. You determine which fabrics require connectivity, and then specify the devices allowed
to communicate across fabrics. The router does not provide 100% any-to-any connectivity between
fabrics, but it does meet most SAN requirements.
Fibre Channel routing implementations
With Fibre Channel routing, you can create a routed fabric by:
• Connecting several fabrics using a router or a switch with router functionality
• Partitioning a fabric into several Virtual Fabrics
• Dividing a single fabric into several smaller Virtual Fabrics or VSANs
Fibre Channel routing techniques
This section describes the following Fibre Channel routing techniques:
• B-series routing connects independent fabrics (SAN islands), as shown in Figure 14 (page
47). HP-supported B-series router products include:
◦ 8 Gb/s switch models with license enabled integrated Fibre Channel routing
◦ HP StorageWorks 1606 Extension SAN Switch (1606 Extension SAN Switch)
◦ HP StorageWorks DC SAN Director Multi-protocol Extension Blade (DC Dir Switch MP
Extension Blade)
◦ 400 Multi-protocol Router (400 MP Router)
46 Fibre Channel routing