User`s manual

Preliminary
Introduction
SANbox-16STD Fibre Channel Switch
5-2 Multi-Chassis Fabrics 59012-03 Rev. A Installer’s/User’s Manual
The term “cascade” indicates that chassis are connected in a row “one-to-the-
next”. You may optionally have chassis interconnections from the last chassis back
to the first chassis. Any port on a SANbox chassis that is placed in a cascade
topology can be either a user port (a port connected to users) or a T_Port
(connected to other Switch chassis). Connect any SANbox port to another Switch
and the port configures itself as a T_Port. All chassis in a cascade topology have a
Stage Type of Input-Output/Transfer (IO/T) or SL Private Loop.
The default is IO/T.
The term “mesh” indicates that each chassis has at least one T_Port directly
connected to each other chassis (each chassis connected to each other chassis).
Any port on a SANbox chassis that is placed in mesh topology can be either a user
port (connected to users) or a T_Port (connected to other Switch chassis). Connect
any SANbox port to another Switch and the port configures itself as a T_Port. All
chassis in a mesh topology have a Stage Type of Input-Output/Transfer (IO/T). The
default is IO/T.
A Multistage Switch consists of chassis configured in two different stage types, an
Input-Output/Transfer (IO/T) stage type, and a Cross-Connect (CC) stage type.
Two or more chassis with the IO/T stage type supply user ports to connect to the
users, and T_Ports that connect to one or more chassis with the CC stage type. The
chassis with the CC stage type supply interconnections for the T_Ports. Any
SANbox chassis can function as an IO/T stage type or as a CC stage type. Switch
management allows you to designate the stage type of any chassis as IO/T or CC.
The default stage type for any chassis is IO/T. Connect any port on a chassis with
an IO/T stage type to another chassis and the port configures itself as a T_Port. All
ports on a CC stage type are T_Ports
Choosing a Topology
The topology you choose depends on the following major fabric requirements:
• The size of the fabric (number of user ports required),
• The amount of latency the users can tolerate (number of chassis hops and
interconnection media delay between the source port and the destination
port),
• The bandwidth between chassis (the number of T_Port paths between inter-
connected chassis),
• The physical distances required between users in a “campus” distributed
fabric verses a centrally located fabric.
• MKII compatibility. SANbox switch fabrics support MKII switches as IO/T
chassis in mesh and Multistage topologies.
These topics are discussed for each topology later in this section.