Cisco BPX 8600 Series, Руководство по установке и настройке

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21-4
Cisco BPX 8600 Series Installation and Configuration
Release 9.3.0, Part Number 78-10674-01 Rev. D0, July 2001
Chapter 21 Configuring ATM Connections
Traffic Management Overview
Traffic parameters are defined as:
•
Peak Cell Rate(PCR) in cells per sec
The maximum rate at which a connection can transmit.
• Cell Delay Variation Tolerance (CDVT) in usec
Establishes the time scale over which the PCR is policed. This is set to allow for jitter (CDV) that
is introduced for example, by upstream nodes.
• Maximum Burst Size in cells (MBS)
Tthe maximum number of cells that may burst at the PCR but still be compliant. This is used to
determine the Burst Tolerance (BT) which controls the time scale over which the Sustained Cell
Rate (SCR) is policed.
•
Minimum Cell Rate(MCR) in cells per second
The minimum cell rated contracted for delivery by the network.
QoS (Quality of Service) parameters are defined as:
• Cell Delay Variation (CDV)
A measure of the cell jitter introduced by network elements.
•
Maximum Cell Transfer Delay (Max CTD)
The maximum delay incurred by a cell (including propagation and buffering delays.
• Cell Loss Ratio (CLR)
The percentage of transmitted cells that are lost.
Congestion Control Feedback:
•
With ABR, provides a means to control flow based on congestion measurement.
MCR x
QoS Parameters
Pk-to-Pk CDV x x
Max CTD x x
CLR x x x nw specific
Other Attributes
Congestion Control
Feedback x
Table 21-1 Standard ATM Traffic Classes (continued)
Attribute CBR rt-VBR nrt-VBR UBR ABR