Minimum Scr And Pcr - Cisco BPX-BXM-155-8DX Installation And Configuration Manual

BXM Capabilities
VBR Service:
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ABR Service:
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UBR Service:
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Minimum SCR and PCR

The minimum Sustainable Cell Rate (SCR) and Peak Cell Rate (PCR) of a connection supported by the
BXM and UXM cards, including enhanced modes, was 50 cells per second (cps) or 19.2 Kbps. These
values were set to maintain a policing accuracy with 1% when policing is performed on a BXM or UXM
card. Because of this limitation, it was impossible to offer and differentiate connection services on a
UXM or BXM at speeds less than 19.2 Kbps (50 cps).
In Release 9.3.0, the switch software supports connections with policing enabled and with SCR and
PCR values as low as 12 cps on the BPX switch, with certain card limitations.
Use the dspcd command to determine if this feature is supported on a given slot.
Use the addcon command to set the minimum SCR and PCR values.
Cisco BPX 8600 Series Installation and Configuration
5-6
– Peak Cell Rate (PCR)
– Cell Transfer Delay Variation (CTDV)
Usage Parameter Control (UPC) and Admission Control
UPC: Ingress rate monitoring and cell tagging per ITU-T I.371 for:
Sustained Cell Rate (SCR)
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Peak Cell Rate (PCR)
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– Burst Tolerance (BT)
CLP tagging, enabled or disabled on a per VC basis at the Ingress side
Based on Virtual Source Virtual Destination (VSVD) per ATM Forum TM4.0
VSVD
VSVDs provide Resource Management (RM) cell generation and termination to support
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congestion control loops
A virtual connection queue (VCQ) is assigned to a VC in the ingress direction
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VCQ configurable parameters
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– CLP Hi and Lo thresholds
Maximum queue depth
Reserved queue depth
Congestion threshold
ABR congestion control
Based on Explicit rate stamping/EFCI cell tagging and ingress rate monitoring per ITU-T I.371
ABR with Virtual Source Virtual Destination (VSVD)
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ABR with Explicit Rate (ER) stamping/EFCI tagging
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ABR with ForeSight
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B
ased on UPC and admission control including EPD
Based on Explicit Rate Marking/EFCI cell tagging and ingress rate monitoring per ITU-T I.371
Chapter 5 BXM Card Sets: T3/E3, 155, and 622
Release 9.3.0, Part Number 78-10674-01 Rev. D0, July 2001