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The method for cascading ServSwitch CX units is straightforward
and requires no hardware settings or lengthy configuration process.
This is due to the Port Direct communication system that allows
them to locate each other and share information.
The method of linking ServSwitch CX units is the same regardless
of the cascade level, or number of devices attached. Put simply:
• A single cascade link is made by connecting a COMPUTER
COnnECTiOns socket of one unit to a CATx UsER PORTs
socket of the unit below it.
Such a single link would allow just one user from the higher
ServSwitch CX unit to access any of the server systems attached
to the lower one. However, a single link can cause a bottleneck
for multi-user systems and cause port numbering problems, so the
minimum permissible group link between ServSwitch CX units is
a triple (quad cascade links are recommended). These allow three
or four users to simultaneously access server systems situated
anywhere within the cascade tree.
When triple or quad cascade links are made between units, each
ServSwitch CX will automatically recognise the links and treat
them accordingly. The links within a triple or quad group will then
be allocated to users according to their general availability in that
group, not as specific individual lines. To do this, each link group
has an access number, which is determined by the ports to which
they are connected on the switch.
For instance, a quad group connected to server ports 1, 2, 3 and
4 of a ServSwitch CX unit would always be known as 41, the next
quad group connected to ports 5 to 8 would always carry the
number 42, and so on. The diagram here summarises the ports to
which triple and quad groups must be connected and the resulting
group numbers attained in the positions here
The central purpose of the link group system is that each user can
use a unique address to locate a particular server. However, as with
the Internet, the route to get there could be slightly different each
time. This avoids any route blocking that could easily be caused by
other users occupying any specific link lines.
Note: Triple and quad link groups may be mixed on one unit
providing the differing link groups lie within appropriate port
boundaries shown opposite - see Tips for successful cascading
for more details.
Port boundaries and numbering for triple link groups
(sixteen port models use groups 31 to 35 only)
Port boundaries and numbering for quad link groups
(sixteen port models use groups 41 to 44 only)
See also
• Addressing servers in a cascade
• Connecting ServSwitch CX units in cascade
• Testing specific links to cascaded servers