Multiple Bridging Modes; Figure 7. Typical Configuration With Switches Using Multiple Bridging Modes - Cabletron Systems SmartSTACK STS16-20RM Installation And User Manual

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Multiple Bridging Modes

The STS16-20RM and the STS16-20FRM each supports four different switching
modes to provide maximum flexibility in all installation environments. The
switching modes are source route switching (SRS), source route bridging (SRB),
source route transparent (SRT) and SRT/SRB. The switch operates on two levels
(BRF and CRF) as outlined in the following.
Figure 7. Typical Configuration with Switches
Using Multiple Bridging Modes
The switch bridging modes are founded on the concept of logical rings (LR) or
logical segments in Ethernet. The logical ring is represented on the switch by the
DTR (IEEE 802.5r) standard's concentrator relay function (CRF). A logical ring
may consist of interconnected CRFs on different switches.
Each port on the switch belongs to a CRF, which is a logical grouping of ports
within the switch. A CRF can consist of any number of ports within a switch or a
switch stack. The ports within a CRF do not have to be adjacent.
The logical rings and, subsequently, the CRFs, are assigned a unique ring number
each when the switch performs source routing functions. The bridging is performed
through the logical entity of the bridge relay function (BRF).
SmartStack STS16-20RM/STS16-20FRM Token Ring Switches, P/N: 9032957-01 Switch Overview