Greetings all;
I am building a test rig for our p2p application and am trying to
simulate conditions on the public Internet, specifically latency and
packet loss. As such I need to create distribution graphs for both
these quantities between two arbitrary points of the network. Has
anyone done any work in this area, or have any pointers?
Apologies if this has been asked before. My Googling (hmm, do
initial caps stay after verbage?) led only to highly complex analyses
for the purposes of better TCP algorithms. While this is no doubt
worthy work, it is far too in-depth for my requirements. I only need
roughly correct distributions so that I can be confident that
successful network operation in the test rig is likely to mean
successful operation on the Public Net (at least regarding packet
loss and latency...)
Some playing around with Excel, with no more exact criteria than
'that looks about right' produced the following formulae:
Packet Loss (probability than on a given connection between two
arbitrary nodes, a particular packet will get lost)
P = (1.2^n)/800000000 for n = [1, ..., 100], n chosen randomly once
for each connection
When n=0, P=0; n=50, P=0; n=100, P=0.1
Latency (delay in packet reception on a given connection between two
arbitrary nodes)
L = (1.04^n')*20 ms for n' = [1, ..., 100], n' chosen randomly once
for each connection
When n'=0,L=21; n'=50, L=142; n'=100, L=1010
Does this sound believable? Of course this assumes constant latency
and packet loss for the life of the connection, which is a gross over-
simplification, but I don't have any feel for what would be 'about
right' for variance over time for the above figures. Additionally n
and n' are chosen independently; it seems likely they'd be correlated
to an extent, but to what extent I don't know. My plan is to build
data collection into our app so that I can create a more accurate
test rig for 1.1.
Any feedback, comments, flames etc welcomed, on-list or off
Cheers
Will
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