System management buses, Smb-1 bus, Smb-10 bus – Cabletron Systems 9T428-16 User Manual
Page 29: System management buses -5, Smb-1 bus -5 smb-10 bus -5
3-5
Operation
Spanning Tree Algorithm is a hierarchy (or tree) of priorities that bridges establish
between themselves. This hierarchy guarantees that primary and redundant data
paths are clearly deÞned at all times, so that the network is continuously available
to users.
In a multiple bridge environment, one bridge in the network establishes itself as
the root bridge. As the root, this bridge has priority over all other bridges. In a
Spanning Tree, all of the bridges must determine which bridge is the root, and
then determine their own relative priority within the network.
System Management Buses
There are two management channels within the SmartSwitch 9000 system: the
SMB-1 and the SMB-10. These buses provide out-of-band management and
inter-module management communication.
SMB-1 Bus
The SMB-1 is a 1Mbs management bus located within the SmartSwitch 9000. This
bus is utilized by all diagnostic controllers in the system including connectivity
modules, power supply modules, and the environmental module. The SMB-1
transports inter-chassis information between system components, such as power
and environmental information, as well as diagnostic messages. Periodic
loop-back tests are performed by all modules which share this bus to ensure the
validity of SMB-1. In the event a failure is detected on SMB-1, the SMB-10 may be
used as an alternate communication channel.
SMB-10 Bus
The SMB-10 is a 10Mbs management bus located within the SmartSwitch 9000
which is also used for inter-chassis communication of modules as well as serving
as an out-of-band management channel into the SmartSwitch 9000. The SMB-10 is
externalized from the chassis via an optional Ethernet Port Interface Module
(EPIM) located on the front of the Environmental Module. Through an EPIM
connection, full SNMP management of the SmartSwitch 9000 is available out-of-
band from user data. Modules which share the SMB-10 bus periodically send out
loop-back packets to ensure the validity of SMB-10. In the event a fault is detected
on the SMB-10, the SMB-1 can be used as an alternate communication channel by
the modules.