3Com 3C63400-3AC-C - PathBuilder S700 Switch Reference Manual page 112

98 C 4: P B
HAPTER ATH UILDER
LAN
Circuits Set Up on PathBuilder S700 #1
PVC
#1
#2
Forward and Reverse VCCs Match in
this Example. VCCs are Unidirectional.
S700 M A
ODULE AND PPLICATION
Once you have entered all PVCs, the bridge learns the network addresses for the
local and remote sites and starts bridging packets to the correct destination by
segmenting the packets into cells which are destined to a remote PathBuilder
S700 port. See Figure 61. The ATM network will transport the cells according to
the VPI/VCI headers.
Figure 62 shows three PathBuilder S700s configured to provide LAN connectivity
between three different LAN segments. This example is a simple configuration
which only uses 1 port on 1 Ethernet port card in each PathBuilder S700.
Figure 62 LAN Connectivity
Circuits Set Up on PathBuilder S700 #2
PVC
#1
#2
Bridge
Forward Known
Table
DS3 UNI 1
1
Broadcast
Unknown
PathBuilder
S700 #1
END1 END2 VPI/VCI Conn To
LAN1 DS3 0/200
LAN1 DS3 0/300
Each Ethernet port will run Bridging (Learning) programs to determine if received
LAN packets should be passed to the WAN on a specific PVC. In the example
shown in Figure 62, multi-port bridging software will determine if packets will be
passed or dropped. When a packet comes in from LAN 1 port and the Bridge code
does not have the destination MAC address associated with one of its logical ports
(Ethernet, PVC #1, PVC #2), it will broadcast the packet on all PVCs attached with
this port. Once Packets are received from the WAN on specific PVC logical ports,
their source addresses will be learned and associated with the logical port. Once
you and your carrier have set up PVCs to all remote PathBuilder S700 Ethernet
ports, the Bridging code will do the rest. For further information on bridging, see
"Bridging" later in this chapter.
O
VERVIEW
END1 END2 VPI/VCI
LAN2 DS3 0/100
LAN2 DS3 0/300
ATM
Switched
Network
Port P1
Circuits Set Up by the Carrier
PVC END1 VPI/VCI1 End2
#1 P1 0/200
#2 P1 0/300
#3 P2 0/300
LAN2
LAN3
PathBuilder S700 #2
Conn To
LAN1
LAN3
DS3 UNI 2
Port P2
Port P3
VPI/VCI2
DS3 UNI 3
P2 0/100
P3 0/100
P3 0/200
PathBuilder S700 #3
Circuits Set Up on PathBuilder S700 #3
PVC END1 END2 VPI/VCI
#1 LAN3 DS3 0/100
#2 LAN3 DS3 0/200
LAN
2
LAN
3
Conn To
LAN1
LAN2