BXM T3/E3, 155, and 622 6-19
BXM Functional Description
Egress
The egress flow of ATM cells out of the BXM when the card is configured for port (access) operation
is shown in Figure 6-10.
ATM cells are routed to the BXM-622 via the BPX Backplane/Stratabus from the BPX crosspoint
switch, applied to the DRSIU, then to an egress queue per class of service, and then served out to the
SUNI (OC3/OC12) or Mux/Demux (T3/E3) which processes the ATM cells into frames, processing
the cells from the ATM layer to the physical and on out to the CPE connected to the port(s) on the
BXM backcard. For ABR cells, additional functions are performed by the SABRE ABR connection
controller, including: VS/VD, Foresight, and virtual connection queueing.
Figure 6-10 BXM Port (Access, UNI) Egress Operation
S6168
SUNI
ACP
ASIC
SABRE
SIMBA
RCMP
DRSIU
Scheduling and ABR Engine
Serial I/F and Multicast Buffer ASIC
Routing Ctl, Monitoring, & Policing ASIC
Dual Receiver Serial I/F Unit
SONET/SDH UNI ASIC
Sub-system Processor
Application Specific Integrated Ckt
Control/Admin Processor
(ACP)
Cell Memory
Q-Database Stats Thresh
BPX
Backplane/
StrataBus
800 Mbps
Ingress
to BPX
Switching
Matrix
1.6 Gbps
Egress
from
BPX
Switching
Matrix
DRSIU
BPX
Fabric
Backplane
SIMBA
RCMP
Route
Control,
Monitoring,
Traffic
Policing
SUNI
for
OC3
or
OC12
or
Mux/
Demux
for
T3/E3
Back
Card
T3/E3
8 or 12 port
or
OC155.52
Mbps 4 or 8
port
or
OC12
622.08
Mpbs
1 or 2 port
To
UNI
CPE
ABR
Connection
Controller
SABRE
ABR
Connection
Controller
SABRE
Ingress
Queue
Engine
QE
Engress
Queue
Engine
QE
Cell Memory
Q-Database Stats Thresh
