Madge Networks Token Ring Switch - Manual (Page 53)

53
Smart DeskStream Technical Presentation 53
Use BRF to set one of the ports to a different ring
number
This is a legal configuration - both uplinks will be
active
n Load sharing, resilient connectivity
Source Route Switching
Introducing multiple uplinks - 3
101
BRF
Ring Number 102
Active
Active
A
Dual uplinks to the same backbone switch
This is an illegal configuration - two ports on the
same switch cannot connect to the same ring
If middle DeskStream fails, both DeskStreams
retain backbone connectivity
What do we need the BRF for?
One use is in resilient networks. The DeskStream replaces the
shared medium hubs which are often connected to two backbone
switches to ensure a connection.
As we have seen, connecting two CRF ports to one Ringswitch is an
illegal configuration and will fail. If we need to connect this way -
perhaps to ensure maximum connectivity for a DeskStream stack if
one fails catastrophically - then the BRF with a different ring number
makes this an allowable configuration.
We will need to manage the path costs to ensure that standby (SR)
or blocking (Transparent) ports are in the Ringswitch.