HP StorageWorks 4000/6000/8000 - Enterprise Virtual Arrays Reference Manual page 120

Maximum number of total domains per backbone fabric
WWNs Maximum number of local WWNs per backbone fabric
Hop count Maximum number of hops between switches (including routers) in a Meta SAN
45)
400 MP Router and MP Router Blade hop count
The 400 MP Router and MP Router Blade are counted in the same way as a Fibre Channel switch
when determining the fabric hop count
through an MP Router must adhere to both the B-series 7-hop limit within an edge fabric and the MP
Router 12-hop limit .
400 MP Router and MP Router Blade usage
Use an MP Router Blade:
If you want to add multiple fabrics to a Meta SAN, and one of those fabrics contains a 4/256
SAN Director, DC SAN Backbone Director, or DC04 SAN Director with an available slot for an
MP Router Blade
NOTE:
All devices connected to the SAN Director Fibre Channel ports are part of a backbone fabric.
If you want to share up to 256 local devices in a backbone fabric with multiple edge fabrics
For FCIP, if there are 4/256 SAN Directors, DC SAN Backbone Directors, or DC04 SAN Directors
at both the local site and remote site
Use a 400 MP Router:
If you do not have a 4/256 SAN Director, DC SAN Backbone Director, or DC04 SAN Director,
and do not plan to use one
If you have a 4/256 SAN Director, DC SAN Backbone Director, or DC04 SAN Director, and do
not want to use it as a backbone fabric
For FCIP, if there are no 4/256 SAN Directors, DC SAN Backbone Directors, or DC04 SAN
Directors at the local site or remote site
For use-case configuration examples, see the 400 MP Router and MP Router Blade use-case white
papers at http://h18006.www1.hp.com/storage/sanwhitepapers.html?jumpid=reg_R1002_USEN.
120 B-series switches and fabric rules
Hop count scalability
(Figure 45 on page 126). Devices communicating across fabrics
42
512 (32 edge fabrics)
1,280 (1 edge fabric)
(Figure 12