Poplar Proxies don't reach 3 meg speed

[IanUK]

here is link

http://www.hostingfreak.net/50MB

That site appears to be in Germany, I too get 330k from it with my default Proxy, USA sites are still only 150k max - nothing has changed here

cheers

Ian

[Firetrap]

Just to let everyone know, NTL techs are looking into this problem! More news will follow once some testing has been carried out...

[Chrysalis]

IanUK - Yeah I know its in germany, but originally I was getting 150 KB from eu/uk and usa, now it seems to be somewhat improved so someone must have took notice of this thread

Firetrap - Thats good to hear.

[simbr]

Originally Posted by Ignition

No, the NetApps are meatier boxes. Load related perhaps.
That list is out of date. Swansea is definitely not Inktomi.

I've just checked Swansea's proxies and they are Inktomi's (Traffic-Server/5.2.4-59306)

I've added up-to-date details of which proxies are Inktomi's to my list

[IanUK]

Just to let everyone know, NTL techs are looking into this problem! More news will follow once some testing has been carried out...

Thats good news, I'm away now for a fortnight or so, so hopefully when I return some progress might have been made

cheers

Ian

[Chrysalis]

thanks, am I right in thiking the ones that have "traffic-Server/5.2.4-59306" are the faster ones? I am on 2mbit now so the problem wont be as bad for me now.

[Eusa]

Originally Posted by mr-b

Ping statistics for 216.168.3.20:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 175ms, Maximum = 269ms, Average = 203ms

I don't think I've ever seen such a detailed, or useful fault report.

200ms RTT is far too high to get 3Mbit/s with the tcp window the netcaches are advertising.

Tracing a single download ( at the origin server )...

Inktomi
max win adv: 63712 bytes
min win adv: 1448 bytes
avg win adv: 25236 bytes

NetCache
max win adv: 17520 bytes
min win adv: 144 bytes
avg win adv: 9810 bytes

BDP for Dummies:
http://www.speedguide.net/bdp.php

And if you really need to get to sleep...
http://www.tcpipguide.com/free/index.htm

The Inktomi caches probably just use the ( possibly tweaked ) underlying OS TCP behaviour, and happily ramp up from a small initial window to ~64K, which is good for 375Kbyte/s upto 175ms (didn't advertise window scaling).

The NetCaches are a bit different and with the window advertised above, they'll only be good for 375Kbyte/s if the orgin servers are under ~40-50 ms (rtt) from the cache. It's tweakable, I guess that's what the techs are looking at (either that or they are going to move the entire internet within 50ms!), but larger windows = fewer connections.

On a cache hit none of this matters.

[Chrysalis]

yeah so we found the problem thats a good thing

east usa is usually under 150ms, west usa is nearer 200ms so that is just out of range of a 65k rwin but I think if they can get it set at 65k then most of websites will be well covered.

[IanUK]

Hi Eusa,

I didn't think I'd see your nick again once I left Freeserve's support Newsgroups

Well, something has happened - Easynews now gives me 376k from a single thread using Default Poplar - as does the Supernews link I posted earlier.

Hooray ! - no more time to test - I'm off on Holiday - but thanks to whoever tweaked whatever !

[Eusa]

Originally Posted by IanUK

Hi Eusa,

I didn't think I'd see your nick again once I left Freeserve's support Newsgroups

Well, something has happened - Easynews now gives me 376k from a single thread using Default Poplar - as does the Supernews link I posted earlier.

Hooray ! - no more time to test - I'm off on Holiday - but thanks to whoever tweaked whatever !

LOL. Hello.

Came across this thread while googling for before/after upgrade reports regarding latency. Only use my NTL connection for gaming and couldn't for the life of me find my NTL details, so thought I'd see if it was worth the effort to search for details / call Support. Since it currently works, I have a faster connection I use for (rare) downloading, and will at some point be automagically upgraded I'll not bother.

It looks like Poplar (at least the 1st one I tried) is now advertising 70080, which has fixed the problem for you.

[downquark1]

Just a bump, there are still the manchester proxies and maybe many more that need investigating.

[Chrysalis]

is it only poplar proxies fixed or all of them now fixed?

[Eusa]

Originally Posted by Chrysalis

is it only poplar proxies fixed or all of them now fixed?

Only "winn" and "popl" (from some list of proxies posted elsewhere in forum) are advertising large windows to clients ( which was quicker to test that checking the origin side ).

Large windows to clients won't ( erm, well.. shouldn't ) be useful, as the client to cache rtt is so low.
Guess they've just upped it for 0.0.0.0/0, and are now comparing a few changed caches to unchanged ones.

[Chrysalis]

ok thanks Eusa, is there a easy way for me to check myself, and also are ntl planning on rolling this change out to all proxes nationwide?

[Eusa]

Originally Posted by Chrysalis

ok thanks Eusa, is there a easy way for me to check myself, and also are ntl planning on rolling this change out to all proxes nationwide?

If you have root access to a webserver, then you can easily tcpdump traffic from the proxy, and just look at the "win" value on the initial SYN from the proxy, and the last FIN.

tcpdump / ethereal or another packet dumping tool can also be used client side to do the same thing (which is what I did earlier), but they could well change the client facing window to be small ( it doesn't need to be big, but currently it is on the first cache in "winn" and "popl" ).

I would just wait for Firetrap or A N Other to say when they think they've got the problem licked. Until then multiple tcp connections will get around most problems for anything that doesn't require high bandwidth over a single connection.

If you want to have a play with tcpdump/ethereal and need any help drop me a PM, which I think I've enabled? If not pipe me :-)