Filter
Top Products
6-22 Cisco BPX 8600 Series Reference
BXM Functional Description
Detailed Description, Port (UNI) and Trunk Modes
The following provides a summary of the principal functions performed by the major functional
circuits of the BXM.
DRSIU
The DRSIU provides a total egress capacity from the BPX switch fabric of 1.6 Gbps.
SONET/SDH UNI (SUNI)
The SUNI ASIC implements the BXM physical processing for OC3 and OC12 interfaces. The SUNI
provides SONET/SDH header processing, framing, ATM layer mapping and processing functions
for OC12/STM-4 (622.08 Mbps) or OC3/STM1 (155.52 Mbps).
For ingress traffic, the BXM physical interface receives incoming SONET/SDH frames, extracts
ATM cell payloads, and processes section, line, and path overhead. For egress traffic ATM cells are
processed into SONET/SDH frames.
Alarms and statistics are collected at each level: section, line, and path.
DeMux/Mux
The Demux/Mux and associated circuits implement the BXM physical layer processing for T3/E3
interfaces, providing header processing, framing, ATM layer mapping, and processing functions for
T3 at a 44.736 Mbps rate or E3 at a 34.368 rate.
RCMP
Usage Parameter Control (UPC) is provided by the RCMP. Each arriving ATM cell header is
processed and identified on a per VC basis. The policing function utilizes a leaky bucket algorithm.
In addition to UPC and traffic policing, the RCMP provides route monitoring and also terminates
OAM flows to provide performance monitoring on an end-to-end per VC/VP basis.
Traffic policing and UPC functionality is in accordance with the GCRA as specified by ATM
Forum’s UNI 3.1 using dual leaky buckets.
• Leaky Bucket 1 utilizes:
— Peak Cell Rate (PCR)
— Cell Delay Variation Tolerance: CDVT
• Leaky Bucket 2 utilizes:
— Sustainable Cell Rate (SCR)
— Maximum Burst Size (MBS)
In addition, two selective cell discard thresholds are supported for all queues for discard of CLP=1
cells should congestion occur.