HP 600 Series, Services And Applications

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Bridging Service
The HP router can operate as a multiport bridge. The bridging service may
be enabled independently of any of the routing services; if not enabled, then
the router will discard packets with protocol types not enabled or supported
(such as IBM SNA or DEC LAT). It is possible to use the HP router solely as
a bridge by not enabling any of the routing services.
This bridging service operates at the media access control (MAC) sublayer
of the data-link layer of the OSI reference model.
As an Ethernet/IEEE 802.3 transparent bridge (or learning bridge), an HP
router supports a variety of filtering options at the MAC layer, such as
source and destination address and protocol type. The IEEE Spanning Tree
Protocol (STP) is available for management of bridged networks with mesh
topologies. STP allows a bridged network to have redundant paths. In the
event of a primary link failure, a backup link takes over, thereby ensuring
continued data transmission between all reachable network segments.
Translational bridging is used between FDDI and either Ethernet or IEEE
802.3 networks. Source-route translational bridging is used for bridging
between token ring (IEEE 802.5) and Ethernet or IEEE 802.3 networks.
These addressing schemes differ at the data-link layer, specifically at the
MAC layer.
Source-routing bridging is used to connect token rings that contain systems
communicating with non-routable protocols such as IBM SNA or NetBIOS.
Thus, when an HP router is configured for source-routing bridging, it can be
used in any application that would otherwise be performed by an IBM
Source Route Bridge. Transparent (also known as learning) bridging is
always enabled with the bridging software, so that when source-routing
bridging is performed concurrently, the HP router is known as a source-
routing/transparent (SRT) bridge.
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