snubbing - why does it happen

[snu2149]

i used older microtorrent (1.6.x) and now latest version

and on some torrents i always get DS flag so even seeders

have 100% of torrent i am blocked by this S flag and unable to download nothing.

i did found older topic on this forum about this issue but nothing was

resolved in this matter.

so i ask is there a cure for this and why is it happening ?

[Switeck]

Do you have your upload speed set too high?

[snu2149]

not realy, i put on all my torrent uploads set to 5 k/s (per torrent)

because my max upload by ISP is ~16 k/s

[jewelisheaven]

Reading the glossary in the µManual (found below) and also the excellent http://dessent.net/btfaq

snubbed

If the client has not received anything after a certain period (default: 60 seconds), it marks a connection as snubbed, in that the peer on the other end has chosen not to send in a while. See the definition of choked for reasons why an uploader might mark a connection as choked. The real function of keeping track of this variable is to improve download speeds. Occasionally the client will find itself in a state where even though it is connected to many peers, it is choked by all of them. The client uses the snubbed flag in an attempt to prevent this situation. It notes that a peer with whom it would like to trade pieces with has not sent anything in a while, and rather than leaving it up to the optimistic choking to eventually select that peer, it instead reserves one of its upload slots for sending to that peer. (Reference)

As far as why it happens, the process is automatic and part of the protocol and cycle of rotating peer connections.

Edit: whoops Switeck to the rescue.

Also, be sure you are setting the Ctrl-G settings lower than your rated linespeed or you will be choking the connection.

It is best not to individually micro-manage torrent speeds unless you also use the bandwidth allocation (which doesn't always mean you will say be sending out a fixed 5 KiBps to a peer on HIGH when there is a faster peer on a LOW torrent)

[snu2149]

"Also, be sure you are setting the Ctrl-G settings lower than your rated linespeed or you will be choking the connection."

well my speed is 512/160 kbs

so i set global DL to 40 and UL to 10 k/s

"It is best not to individually micro-manage torrent speeds unless you also use the bandwidth allocation (which doesn't always mean you will say be sending out a fixed 5 KiBps to a peer on HIGH when there is a faster peer on a LOW torrent)"

this i dont understand

[jewelisheaven]

OK, you know how you can right click on a torrent, and go to bandwidth allocation?

Well say for instance you have two torrents, one with the best application ever and you want to share it forever (ratio -1). Also you set it to HIGH priority (utilization of your line if available).

Also you have the recent episode of some webcast you like alot and you don't want it to interfere with any peers on your application torrent so you set it to LOW.

Just because HIGH is more important than LOW does not mean peers on the LOW torrent will not take over unused bandwidth when the HIGH peers cannot accept as much traffic.

Does that make a little more sense?

Edit: double negatives suck.

[snu2149]

well i dont change anything in Bandwidth alocation options.

they are all by default normal.

i only limit speed per torrent

say if i download 2 at same time then i give each DL speed of 25 and UL speed of 5

so i dont get limited on speed below 30 k/s

other than that i dont change anything singificant in microtorrent.

i only also set in adv.options lazzy peer thing on true

coz someone on this board recommmended it in some thread regarding snubbing

[jewelisheaven]

Well that's one way of doing it, and if it works for you then I won't complain

If you check the peers flag column regularly, do you notice when the S goes away. I'm pretty sure the O (optimistic unchoke) happens every minute, taking one S peer and trying to get them to either U or D. (from u and d, the versions of the upload/download that means you two peers will be communicating)

[snu2149]

well its not so good situation

in my current situation, out of 12 100% seeders only 6-7 unfalg S from time to time

others constantly hold S

and then after like 2 minutes or so i get again snubbed by few that unsnubbed me

[jewelisheaven]

Well, as I said the process is automated... forgive me for asking, but have you tried the same peers/swarm in 1.7.5 ?

It sounded like you were having this problem with the deprecated 1.6 line.

[snu2149]

yes i had with 1.6 then i switched to 1.7.5 a week ago coz i thinked

maybe new version fixes this

but if its all automated then i guess theres nothing i can do

btw thanks for patience and help

[jewelisheaven]

Also I guess I glossed over it. Have you tried decreasing total number of running torrents and increasing upload slots... This allows more peers to get the U from you which may in turn keep them from S on you.

[snu2149]

hmm well i set now max number of torrents for DL an UL on 4

and 4 for active torrents running, but dunnno how many slots should i have

for upload, it says 4 at this momment, but for my 160kbs upload i dunno how

much is recommended

[jewelisheaven]

Well as a preferential user I think anything < 10 KiBps is blasphemy.

However the protocol allows 16 KiB to be sent in any 5 minute period without dropping the connection.

[snu2149]

ehm now i dont understand what you wanted to tell

shud i set slots to 16 or ?

[jewelisheaven]

OK. Sorry I used the -bibyte notation most users are unfamiliar with.

What a hard drive manufacturer calls a megabyte is infact NOT a megabyte accordnig to anything which interprets data. This is due to their misguided belief that consumers are too stupid to know the difference between 10^3 and 2^10. In fact the difference is 2% for each order of magnitude involved. This means that for every gigabyte you are losing 6% of your hard drive. To be clearer the smart people.. I think they were at NIST decided that a hard drive manufacturer (and others which use base-10 notation are KB,MB,GB,TB,PB, etc) and the programs and people who use data in BINARY (which is what 1's and 0's are in-fact) use iB suffix. Therefire a kilobyte (KB) becomes a kibibyte (KiB). and there are 1024 KiB in one MiB whereas there are only 1000 KB in one MB.

What you set it to depends on your total upload and how generous you want to be to each of them. My main purpose for suggesting this is that on the rotating basis (every minute or so) you open up X slots to peers. Therefore each X peers will be U from you and if they are interested will get pieces faster.

[snu2149]

ehm... i just wanted to know because my upload speed is weak (160 kbs)

how much slots can i max open and not to choke other torrents that i seed

[Switeck]

You should not have total upload slots exceed your upload speed in KiloBYTES/sec ever.

So 160 kilobits/sec upload is about 18 KiloBYTES/sec upload speed...so no more than 18 total upload slots spread between however many torrents you have (such as 4 per torrent, 4 total torrents...or 3 and 6.)

But to get better results while downloading, each upload slot needs about 3-5 KiloBYTES/sec.

While seeding, upload slots can be set at 5-10 KiloBYTES/sec each...simply because peers have nothing to share till they get a complete piece which is often 1, 2, or even 4 MB in size!

[snu2149]

so are this settings ok then ?

[jewelisheaven]

err you are setup there for 4 torrents @ 10 slots per. Perhaps changing that to 4, and only running 4 torrents concurrently... that would fit within the bounds set above.

[snu2149]

well thats why i have ppl like you to tell me

thanks again