Tracker request fields information

[krosswindz]

I am trying to write a bittorrent tracker as part of my project. I am using utorrent to test the tracker I am writing. I am using the details of Tracker request posted here

GET /announce?info_hash=%f66%ba%d5W%b4%df%85%b1%7d%be%efP%8ae%da%00%be%9c%3c&peer_id=-UT1820-%fd%3bqz%83f%12%db%5eK%8f9&port=42823&uploaded=0&downloaded=0&left=104857600&corrupt=0&key=1230F1E5&event=started&numwant=200&compact=1&no_peer_id=1

I have the following questions about the request which I couldnt understand from the wiki post.

1) What does "corrupt" parameter mean?

2) What is the length for the "key" parameter. Does it have a fixed length like hash_info and peer_id which is 20 bytes.

3) What is the length of "trackerid" parameter. Does it have a fixed length like hash_info and peer_id.

Any help on this is really appreciated.

[DreadWingKnight]

1> Corrupt is the amount of data rejected as corrupted.

2> Non-fixed, usually only 6 bytes

3> Determined by the tracker. Non-fixed.

[krosswindz]

Thanks DreadWingKnight really appreciate your answer.

which of this would be accurate interpretation of corrupt

valid download = downloaded - corrupt

or

actual download = downloaded + corrupt

[DreadWingKnight]

the "downloaded" value sent in the announce request is the validated download amount, not including corrupted pieces.

[krosswindz]

thanks dreadwingknight that has been really helpful. will post other queries here as when.

edit:

Another question on the spec is that are the fields "key" and "trackerid" urlencoded like peer_id and hash_info or are they in hex?