Intel ER8100STUS - Express 8100 Router, Справочное руководство

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Reference.bok : Chapter10 95 Wed Apr 22 10:58:08 1998
95
How Bridging Works
WAN Bridging Services
Bridging Services use the MAC addresses assigned to network devices, where
routing protocols usually require protocol-specific addresses to be assigned to
devices. This makes bridged networks much simpler to implement than routed
networks from the Network Managers point of view.
The use of Forwarding
Tables
Bridging Services use Forwarding Tables to decide where packets should be
bridged to.
■
If a packet received for bridging appears in one or more of the forwarding
tables, it is forwarded to one or more links or discarded as appropriate.
■
packets received for bridging which do not appear in the forwarding tables
are transmitted to all the network segments except the one from which it was
received. Alternatively, the bridge can be set up to discard packets which do
not appear in the forwarding tables.
A full description of bridging using the forwarding tables is given in “Operation
of the Bridge in the Intel Express 8100 Router”, p. 101 . Forwarding tables are de-
scribed in the “Forwarding Tables”, p. 95 .
Forwarding Tables
Forwarding tables
Forwarding Tables are used when deciding where incoming packets should be
bridged to. The following forwarding tables are implemented in the router:
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Destination Forwarding Tables for both Unicast and Multicast packet desti-
nations
■
a Source Forwarding Table for defining destinations for packets from source
MAC addresses
■
a Type Forwarding Table for defining destinations for Ethernet packet types