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Cisco WAN Manager User’s Guide
Version 10.5, Part Number 78-12945-01 Rev. D0, August 2003
Chapter7 Service Class Template Manager
Functional Interaction
•Minimum Priority: The priority at which this C OSB will be serviced to g uarantee its minimum an d
maximum bandwidth requirements. Highest priority = 0; Lowest priority = 15. Range and units:
0-15.
•Excess Priority: The priority at which this COSB will be given acce ss to excess bandwidth. Highes t
priority = 0; Lowest priority = 15. Range and units: 0-15.
In the Threshold ca t e go ry, the following parameters can be modified:
•Maximum: Maximum Threshold.
•CLP High: Cell Loss Priority High Threshold (% of VC QMax) is the highest threshold for the bit
in the header of an ATM cell that ident ifies the cell as eligible for discard within the network under
predefined congestion conditions. Most of te n s e t by the ingress polici ng f u nc tion.
•CLP Low: Cell Loss Priority Low Threshold (% of VC QMax) is the lowest threshold for the bit in
the header of an ATM cell that identifies th e c ell as eligible for discard w it hi n th e n et wo r k un de r
predefined congestion conditions.
•EPD0: Early Packet Discard Threshold. The maximum threshold for CLP (0+1) cells. This value is
a percentage of the MAX_CELL THRESH for the connection. 1000000 is equal to 100%. Range
and value: 0-1000000.
•EFCI Threshold: Ex pl ic i t F or w ar d Congestion Indic ati on. The VC EFCI di s car d threshold. This
value is a percentage of MAX_CELL THRESH. 1000000 is equal to m100%. Range and values:
0-1000000.
•RED: Random Early Discard. The threshold at which the COSB Random Early Discard (RED) is
activated. This thr eshold is a percentage of the MAX_CELL THRESH for the connection. 1000000
is equal to 100%. Range and units: 0-1000000.
•Dscd Alm Th: Indicates the Discar d A larm T hr esh o ld.
In the Miscellaneous cat eg or y, the following parameters can be modified:
•RED Pro Factor: Random Early Discard Probability Factor. The mantissa value of probability for
maximum discard when RED is act ivated. D ete r min ed as 1/ 2^ <valu e> .
•RED Selection: Random Early Discard will drop pa cke ts fro m queu es on a rand om basi s in orde r to
avoid buffer overflow. RED is accomplished by dropping packets on a random basis, which is
determined statistically, when the m ean q u eu e d ep th exc eed s a threshold over a period of tim e,
effectively advising the packet source rou ter t o de creas e it s p ack et ra te.
•WFQ: Weighted Fair Queuing is an a pproximation of the G en er ali zed Processor Sharing (GPS )
scheduling. WFQ can be generally used to give performance guarantees to connections carrying
best-effort packet traffic, where each connection can be guaranteed bandwidth in proportion to its
weight and in a fair manner.
•ERS: Explicit Rate Stamping. Indicates whether Explicit Rate Stamping (ERS) is enabled or
disabled. Range and units: 1=enabled; 2=disabled.
•Best Effort: A Quality of Servic e Class in which no specific t r affic par am eters and no absolute
guarantees are provided. Best Effort in cl ud es UB R an d A BR S er v ic e Types.
•Dscrd Alarm: Enable/disable D isc ard Alarm per VC: Indicates wh et he r D isca rd Alarm has been
enabled or disabled. Range and units: 1=enabled; 2=disabled.
•CLR- Cell Loss Ratio. CLR is a n egoti ated QoS (Quality of Service ) parameter and acceptable
values are network specific. Th e o b je ctive is to minimize CLR provided t he en d- sy stem adapts the
traffic to the changing ATM layer transfer charact eristics. The CLR is defined for a co nn ec tion as
Lost Cells/Total Transmitted Cells.