Filter
Top Products
7-16
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 COSB will be serviced to guarantee its minimum and
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 access to excess bandwidth. Highest
priority = 0; Lowest priority = 15. Range and units: 0-15.
In the Threshold category, 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 identifies the cell as eligible for discard within the network under
predefined congestion conditions. Most often set by the ingress policing function.
• 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 the cell as eligible for discard within the network under
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: Explicit Forward Congestion Indication. The VC EFCI discard 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 threshold 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 Discard Alarm Threshold.
In the Miscellaneous category, 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 activated. Determined as 1/2^<value>.
• RED Selection: Random Early Discard will drop packets from queues on a random basis in order to
avoid buffer overflow. RED is accomplished by dropping packets on a random basis, which is
determined statistically, when the mean queue depth exceeds a threshold over a period of time,
effectively advising the packet source router to decrease its packet rate.
• WFQ: Weighted Fair Queuing is an approximation of the Generalized 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 Service Class in which no specific traffic parameters and no absolute
guarantees are provided. Best Effort includes UBR and ABR Service Types.
• Dscrd Alarm: Enable/disable Discard Alarm per VC: Indicates whether Discard Alarm has been
enabled or disabled. Range and units: 1=enabled; 2=disabled.
• CLR- Cell Loss Ratio. CLR is a negotiated QoS (Quality of Service) parameter and acceptable
values are network specific. The objective is to minimize CLR provided the end-system adapts the
traffic to the changing ATM layer transfer characteristics. The CLR is defined for a connection as
Lost Cells/Total Transmitted Cells.