Specifications

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SERVSWITCH™ AFFINITY
3.4.3 T OPOLOGIES
NOTE
A standard Affinity system can support up to four, eight, or sixteen
independent users, but each of their user ports/KVM user stations has
to be numbered differently: either attached to a Port Card in a different-
numbered slot, or in chassis whose Expansion Cards are set for
different numbering. See Section 3.4.2. If you have users on same-
numbered ports/stations (both on KVM 1, for instance), the users will
share a video bus. Refer to Section 5.3.
The illustrations in this section show the three main topologies (patterns) in which
you can interconnect ServSwitch Affinity units: regular bus, split bus, and ring.
(The arrows in the illustrations indicate video-signal directions from output to
input.) Which of these topologies you use will depend on where your users are, as
explained in the following paragraphs.
NOTE
It is theoretically possible to create branching topologies with the 8- and
16-User ServSwitch Affinity models, but we recommend that you avoid
trying to do so. If you feel that such a topology is necessary for your
application, please call Black Box Technical Support to discuss it.
3.4.3.A Regular Bus
With daisychained 4-User models, use a regular bus arrangement (like the one
shown in Figure 3-5 on the next page) if all of your users are on an Affinity at the
end of the chain. In this topology, the outputs of all Affinity units except the first
unit attach to the input ports of the previous unit in the chain. (The first unit is the
end of the video-signal path.) This means that video is flowing in the same chassis-
to-chassis direction through all expansion ports.
The regular bus topology is also useful in a daisychain of 4-User models if your
users are on different Affinity units but you want to restrict users’ access to certain
CPUs. For example, if users were on Unit 2 in Figure 3-5, they would only be able
to switch to CPUs on Units 2 and 3; they would not be able to switch to CPUs on
Unit 1.
With 8-User or 16-User models daisychained in a regular bus (as shown in
Figure 3-6 on the next page and Figure 3-7 on the page that follows), as many as
four of your users can have access to all CPUs, and the rest of your users will have
access to some subset of the CPUs. In Figure 3-6, the four users on Unit 1 can
access all CPUs, and the four users on Unit 2 can access all CPUs except those on
the first chassis. In Figure 3-7, with sixteen users attached four apiece to Units 1
through 4, the four users on Unit 1 would have access to all CPUs, the users on
Unit 2 would have access to all CPUs but those on Unit 1, the users on Unit 3
would have access to all CPUs but those on Units 1 and 2, and so on.