This invention gives the way and equipment for measuring the size of queue that intermediate router of WAN has. In general this parameter is not opened from WAN service providers, however, it is important for tuning burst size in LAN side.
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Buffer Size Measuring Equipment for WAN
This invention gives the way and equipment for measuring the size of queue that intermediate router of WAN has. In general this parameter is not opened from WAN service providers, however, it is important for tuning burst size in LAN side.
Network environment this invention applied
W A N
C ircuit
O ptical Fiber
This invention is to know how m any size is this queue?
D
Sender Receiver
Queue
Assuming the rate of pouring into the queue as Rin [packet / sec], the rate of emitting
from the queue as Rout [packet / sec]
Upper limit of Rin is determined by LAN bandw idth (e.g.1Gbps). Rout is determined by
W AN bandw idth (e.g. 150M bps).
The rate of increasing the packets of the queue is Rin - Rout.
Assuming the queue size as D [packet], the time until overflow of the queue as S [sec]
- S = D / (Rin - Rout)
Assuming successive received packets without drop as N,
- N = Rin x S
Delete S in the former tw o equations
- D = N x (Rin - Rout) / Rin
The measuing equipment
Term inal E dge R outer Term inal
E dge R outer
LA N
LA N
P acket
Q ueue
The principal of the measurment
Rate Rin
Rate Rout
Drop
N
1
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Terminal Edge Router Terminal
Edge Router
Client Server
WAN
LAN LAN
Control data
Measurement
Result
Controller
Controller
User I/F
Calc.
Judgment of Received
IP packet
IP Packet Sender
IP Packet Receiver
Flow of Procedure
M easuring R out (W A N bandw idth)
M easure the m axim um rate that...
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