Intel ER8100STUS - Express 8100 Router, Reference Manual

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Reference.bok : Chapter10 101 Wed Apr 22 10:58:08 1998
101
How Bridging Works
WAN Bridging Services
Forwarding tables used
Bridged packets are processed by all the Forwarding Tables before being for-
warded. A packet which is allowed to pass by one Forwarding Table can therefore
be rejected by another Forwarding Table.
Operation of the Bridge in the Intel Express 8100 Router
Loop-Back check
When a packet is received for bridging, a check is performed to determine if the
packet was bridged to the network segment by the router itself—this is called a
“loop-back” check. Packets are discarded if they are received on the same link
that they were transmitted.
Forwarding
A packet which is not discarded by the loop-back check is checked against the
Forwarding Tables (as described in the previous section) to find out which net-
work segment(s) it should be transmitted. The packet is forwarded on the link(s)
allowed by the Forwarding Tables except the link from which it was received.