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Cisco WAN Manager User’s Guide
Version 10.5, Part Number 78-12945-01 Rev. D0, August 2003
Chapter4 Connection Manager
PVC Connections Supported by Release 10 of CWM
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Time Between Fwd RM Cells
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Transient Buffer Exposure(TBE): The n umb er o f R M cel ls t h at can b e s e nt o ut by a v irt ua l
source before waiting for a BRM cell in return.
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Fixed Round Trip Time (in microseconds): The amount of delay expected for an RM cell to
travel through the network to the destination and back again.
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per-VC Weighted Fair Queuing (WFQ): Weighted Fair Queuing is an approximation of the
Generalized Processor Sharing (GPS) scheduling. WFQ can be generally used to give
performance guarantees to connec tions carrying best-effort packet traffic, w h er e e ach
connection can be guaranteed bandwidth in proportion to its weight and in a fair manner.
•SCT Cosb Parameters
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Cosb Number: Class of Servic e B u ffer Nu m b er. The nu m b er th at identifies one of the sixteen
Cosb buffers. A Cosb buffer is a b uffe r that services co nnection s with simil ar QoS requ irements.
Range and units:1-16.
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Cosb MinRate: This field is no longer used and is currently always set to its default value (0).
Range and units: 1- 1000000.
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Cosb MaxReservableRate: This field i s no longer used and is currently alway s set to its default
value (100). Range and units: 1- 1000000.
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Min Priority: The priority at which this COSB will be serviced to guarantee it minimum and
maximum bandwidth requirements. Highe st prior ity = 0; Lo west pr iorit y = 15. Range an d units:
0-15.
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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.
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Cosb Max Threshold: Class of Service Buffer Maximum Threshold. This val ue is a percentage
of MAX_CELL THRESH. 1000000 is equal to 100%. Range and values: 0-1000000.
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Cosb CLP (1) High Threshold: Class of Service Buffer Cell Loss Priority. This value is a
percentage of MAX_CELL THRESH. 1000000 is equal to 100%. Range an d values: 0-1000000.
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Cosb EPD (0) Threshold: Class of Service Buffer 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.
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EFCI Threshold: Explicit Forwa rd Cong esti on Indica tion. The VC EFCI d iscar d thres hold. T his
value is a percentage of MAX_CELL THRE SH. 100 0000 is eq ual to m1 00%. Ran ge and v alues :
0-1000000.
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Explicit Rate Stamping: Indi cates wh ether Exp lici t Rate Stampi ng (ERS) i s enab led or disable d.
Range and units: 1=enabled; 2=disabled.
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Random Early Discard Selection(RED): RED will drop pac k ets fr om queue s on a ra ndom basis
in order to avoid buffer o v er flo w. RED is accomplished by dropp in g pack ets on a ra ndom b asi s,
which is determined statist ically, when the mean queue depth exceeds a threshold over a period
of time, effectively advising the packe t so u rc e r o uter to d ecr ea s e i ts packet rate.
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Random Early Discard Threshold: The threshold at which the COSB Random Early Discard
(RED) is activated. This thres h ol d is a pe rcentage of the MAX_CELL THRESH for the
connection. 1000000 is equal to 100%. Range and units: 0-1000000.
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Random Early Discard Probability Factor: The mantissa value of probability for maximum
discard when RED is activated. Det er min ed as 1/2^<value>.