RE: Peering point speed publicly available?

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1

Latency does have a impact on TCP transfers, now granted the difference between a oc-3 and oc-192 is negligible, but if you stack a lot of T1 connections back to back its going to be a factor in your max throughput across the path.

(Stats below might not exactly be accurate...snipped from another site)

DS3: (1500 bytes * 8 bits/byte) / 44040192 bits/sec = .27 ms (approx)
DS1: (1500 bytes * 8 bits/byte) / 1572864 bits/sec = 8 ms (approx)
DS0: (1500 bytes * 8 bits/byte) / 65536 bits/sec = 183 ms (approx)

If you don't think it does then run some ftp transfers end to end with 1ms of delay, and with 100ms, 200ms, 500ms, 1000 ms

I never said that .002 microseconds is going to have a noticeable difference, but those 10ms - 20ms hops starts to add up. As well as propagation delay as you stated.

-C

2

Lets not put words in anyone's mouth here. Latency does indeed have an
impact on TCP transfers (though it CAN be overcome with decent algorithms
and sufficiently large buffers to keep packets on the wire pending acks).
What I said was that serialization latency has no impact in TCP transfers,
and that the difference between 10Mbps ethernet and OC-192 is only barely
detectable.

(1500 bytes * 8 / 10000000) - (1500 bytes * 8 / 9952000000) = .0012 ms

If you have a DS0, serialization latency is not your limiting factor for
TCP speed. If you have a T-1's worth of data to pass, it doesn't matter if
you're routing it through an unused 10Mbps ethernet or unused OC-192.