Black Box KV162A Manual De Usuario

3. There are several independent data pathways available to carry transmissions through any ServSwitch

Multi: eight pathways for the SB model, four pathways for the EXP and Base Unit models, and only two for
the MX model. Each expansion-port link between two ServSwitch Multis through a pair of Transmit and
Receive Cards is going to require the use of one of these pathways through each of the two Switches every
time signals are transmitted across the link. Whenever all of the pathways in a given Switch are active
(carrying data) at the same time, any attempt by any other user in the system to independently select a
computer channel on that Switch will be ignored.

Refer to Figure 6-6; let’s examine what happens if all of these Switches are ServSwitch Multi EXPs. Say

the user on Switch 0 wants to access computer 1H. A Transmit Card on Switch 1 is connected to a Receive
Card on Switch 0, so this would work if there were fewer users on Switch 1. But because there are four
users on Switch 1, and all of them will be using at least one of Switch 1’s data pathways at all times, Switch 1
has no available pathways left. Therefore the user on Switch 0 can’t establish an independent connection
to computer 1H (although he or she can share access to that computer—see Section 8.3.) However, as
long as the user on Switch 2 has computer 2B selected, the user on Switch 0 can access computer 2K
independently, because the user on Switch 2 is only occupying one of the four pathways through Switch 2.

If all of the switches in Figure 6-6 are ServSwitch Multi SBs, the user on Switch 0 has no problem

independently accessing computer 1H. This connection would only be the fifth for Switch 1, which would
still have three free data pathways available.