A Bridge is deemed to connect 2 different LAN segment
LAN -------MAC Bridge MAC -------- LAN
Source-Route Bridging is designed for interconnecting token ring segments into a bigger LAN.
Originally, Source-Route Bridging was deemed as a universal method for creating large-scale networks. However in actual world, source-route can not meet client's requirement.
Non-Transparent
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The headers of token ring frames that must travers source-route bridge (the frame contains routing information that is used by the bridges to forward the frame thru source-route bridged LAN from src to des), the routing info describes precisely which bridges and segments the frame must traverse to arrive at the des.
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The Source Node is responsible for inserting the routing information into the headers of the token ring frames that must be delivered thru Source-Rout Bridge.
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Source-Route Bridge requires each node to be able to discover and memorize routing information to DES accessible thru Source-Route Bridge.
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Each Ring shall be assigned a unique number.
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Each bridge shall be assigned a unique number with each ring to which the bridge is connected.
Like a transparently bridged LAN, source-route allows redundant paths to exist with a single source-route bridged route LAN. This redundant path helps to be utilized to recover from network component failure.
As designed spec, the source-route bridging got only 2 ports, in order to be bypassed this weired obstacle, can require a significant amount of additional equipment.
A neat solution was devised, it allows multiport source-route bridges to be created, so an abstraction called 'virtual ring'. The operation of such a bridge counts that virtual ring as a regular ring and inserts an extra route designator into all routes and spanning explorers crossing the bridge.
- DLSw, Data Link SW
- RSRB