What Is a Routing Bridge?

The source routing bridge was a proposal to the IEEE 802.1 committee to compete with transparent bridging technology in order to become the standard of the data link layer for LAN connection. When the 802.1 committee decided to adopt transparent bridging, the recommender of the source-route bridge submitted this concept to the 802.5 committee to standardize it, making it the 802.5 LAN interconnection method. .

Source routing bridge

Source routing bridge used to be

Transparent bridges are easy to install, but network resources are not fully utilized. The source route bridge places detailed routing information in the header of the frame when sending the frame. The source station broadcasts a discovery frame to the destination station that wants to communicate, and each discovery frame records the route it passed. When a frame arrives at the destination station, it returns to the source station along its own route. After the source station learns these routes, it selects an optimal route from all possible routes. The header of any frame sent from the source station to the destination station must carry this routing information determined by the source station.

For a period of time, transparent bridges and source-routed bridges developed independently. But the accompanying requirement is to design a way to satisfy the connection between the LANs interconnected by transparent bridges and the LANs interconnected by source-routed bridges. This kind of bridge is called SR-TB (source routed bridge-transparent bridge). This approach proved to be complete, especially when people tried to create a local area network that would use both types of bridges.

Ultimately, all standard bridges must support transparent bridges, and source routing is an optional additional feature.

A transparent bridge with active routing header information forwarding is called an SRT (source route transparent) bridge.

There are many reasons to tirelessly discuss source routing here. This technology has not been completely eliminated, and many people still have to understand and master it. The source routing header is included in the current standard, and the 802 standard still does not seem to intend to eliminate it. But the main thing is its educational significance, which allows us to learn a different method, no matter whether it is good or bad, it does give us an opportunity to gain insight into the inside of the agreement.

Advantages and disadvantages of source routing bridges: Source routing bridges are often used in token ring networks. Only those frames whose destination high order is 1 are concerned.