“Do The Math”

• Calculate needed peak window in bytes. Note that is twice the window needed to fill just barely fill the link...

Wb = 2*RTT*Rb (Rb is the desired data rate in Bytes per second)

• Calculate needed window in packets....

Wp = Wb/MSS

• Calculate needed window scale....

Ws= ln2(Wb/64k) E.g. if Wb = 100kB, Ws=1

• Calculate needed packet rate....

Rp = Rb/MSS

• Calculate needed loss interval. This is the approximate number of bytes that must be sent between successive loss intervals to meet the target data rate....

Li = 3/8 Wb * Wp

testrig pages at NCNE/PSC

Rb = 11.25 MBps (90Mbps)

Rtt = 0.040 sec (40 msec)

MSS = 1440 Bytes

Wb = 900 KBytes

Wp = 625 packets

Ws = 4

Rp = 7813 pps

Li = 211 MBytes!

ploss = 5x10^-6! (0.0005%)

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