Configuring Source Route to Transparent Bridging
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Configuring Source Route to Transparent Bridging

In order to provide switching between source-routed token ring networks supporting the IBM
Spanning Tree, and transparently bridged networks (primarily Ethernet supporting 802.1d
Spanning Tree), commands have been provided in the bridging menu to enable Source Route
to Transparent Bridging (SRTB) on a configured group basis.
It is important not to confuse SRTB with source-route transparent (SRT) bridging. SRT bridg-
ing is the defined method for bridging on source-routed networks. In SRT bridging, all
bridges run the 802.1d Spanning Tree. SRT bridges have the ability to forward a frame based
on source-routing information if a Routing Information Field (RIF) is present. Frames without
a RIF are bridged transparently. SRT does not provide the ability to switch between a pure
source-routed network and a transparent network.
SRTB allows source-routed token ring networks and transparently bridged networks to exist
in the same group, and supports connectivity between end systems on the token ring
network and the end systems on the transparently bridged network.
The SRTB functions in the following network environments:
• Between token ring and Ethernet networks.
• Between token ring networks and Ethernet LAN emulation (LANE).
• Between token ring LAN emulation and Ethernet networks.
♦ Note ♦
Ethernet networks include 10Mbit, 10/100 MB, and
Gigabit networks.