3-6 CHAPTER 3: INSTALLING MODULES INTO THE MSH CHASSIS
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■Firstly, each frame is examined for the destination address, and
passed intact to the port associated with that address. For
10Base-T, fiber or AUI, this is equivalent to passing direct t o the
addressed device. Every other port transmits a frame of the
same length and network timing but with randomized bits:
this is undecipherable. No extra delays are introduced. The
frames are therefore sent securely on a need-to-know basis.
■Secondly, if an unauthorized station appears on a segment
attached to a port, the Network Manager will be informed.
You may choose what action is taken by the Network
Manager. It may just note the fact, or it may automatically
disconnect the unauthorized device by disabling the port to
which that device is attached.
■Resilience: This feature is available for use on point-to-point
media, for example twisted pair and optical fiber. You specify
resilient pairs of ports, each pair consisting of a main port and a
stand-by port. If the management module detects a signal loss in
data transmitting over the segment attached to a ma in port, this
port will be automatically disabled and the data re-routed over
the segment attached to the stand-by port.
■Ethernet Bus Selection: The MSH Ethernet backplane contains
three separate buses, E1, E2 and E3. A configurable jumper on
the module (or converter if you are using ECS modules) allows
you to determine to which bus that module is routed. This allows
you to set up separate networks within the one MSH chassis.
When using this feature you should be aware that:
■You will not be able to collect all statistics from LinkBuilder ECS
modules that are routed to Bus E2 or E3. If you require full
statistics gathering, you must connect ECS modules to Bus E1.
■To ensure that the remote Network Manager has initial access
to the MSH management module and to ensure full statistics
gathering for ECS modules, you are advised to also attach the
management module to bus E1.
■Internal Crossover: Configured via a jumper located on a 10
Base-T Repeater module, this feature allows you to determine
Chassis.bk : CHAPTER3 Page 6 Monday, February 10, 1997 1:11 PM