3Com OfficeConnect 3C840, User Manual

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A-8 A
PPENDIX
A: B
RIDGING AND
R
OUTING
are able to share the same Class B network address, regardless of their
location on the bridged network.
Figure A–4 Open Systems Interconnection Network Layer Model
Open Systems
Interconnection
Network Layer Model
A routing environment allows stations to communicate indirectly.
Following the example in under “Routing IP”, let us assume that a station
on LAN 1 wants to communicate with a network server on LAN 2. The
station on LAN 1, constructs a Layer 2 datalink header (see Figure directly
above), with the source station's hardware address, and also the
destination hardware address of the local router. To direct the packet to
its final network destination, the source station must complete the Layer
3 network header with the destination network address of LAN 2.
840ug.book Page 8 Friday, July 7, 2000 2:23 PM