Cbr Module - 3Com SuperStack II PathBuilder S330 Reference Manual

CBR Module

Each PVC represents the logical circuit being used to connect one PathBuilder
S330/S310 port to a remote PathBuilder S330/S310 port. Once you have entered
all PVCs, the bridge will learn the network addresses for the local and remote sites
and start bridging packets to the correct destination by segmenting the packets
into cells which are destined to a remote PathBuilder S330/S310 port. See
Figure 168. The ATM network will transport the cells according to the VPI/VCI
headers.
Figure 169 shows three PathBuilder S330s configured to provide LAN connectivity
between three different LAN segments. 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 above example, 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 associated 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 S330/S310 Ethernet
ports, the Bridging code will do the rest.
Figure 169 LAN Connectivity
Bridge
Forward Known
Table
DS3 UNI 1
LAN
1
Broadcast
Unknown
PathBuilder
S330/S310 #1
The optional T1-DSX/E1 CBR module provides three T1-DSX or E1 ports (one on
the PathBuilder S310) and one serial port. This module services traffic generated
by your existing PBXs, channels, T1/E1 multiplexers, CSU/DSUs, and video
conferencing devices. This service maps the T1-DSX/E1 service through the AAL1
adaptation layer over a CBR virtual channel connection (VCC). The VCC is
established as a permanent virtual circuit (PVC) and mapped from the PathBuilder
S330/S310's ATM port to another PathBuilder S330/S310 or an ATM Forum circuit
emulation compliant device.
ATM
Switched
Network
Port P1
Circuits Set Up by the Carrier
PVC END1 VPI/VCI1 End2
#1 P1 0/200 P2
#2 P1 0/250 P3
#3 P2 0/250 P3
CBR Module
PathBuilder
S330/S310 #2
DS3 UNI 2
Port P2
Port P3
DS3 UNI 3
VPI/VCI2
0/100
0/100
0/200
PathBuilder
S330/S310 #3
231
LAN
2
LAN
3