[BillyGates]

First of thanks to all the devs for releasing eMule 0.43a!

So after reading through:

http://www.joltid.co.../peercache/faq/

and

http://forum.emule-p...showtopic=46323

I can see the need for an eMule PeerCache FAQ soon.

So some questions I have:

1. Is there any way to tell if PeerCache is being used?

2. If it's really a transparent proxy, what had to be done in eMule to support it? i.e. Transparent http web caches don't require specific changes to the web browser.

3. I -assume- you need to be running on the standard eMule ports to support this?

4. If a change had to be made to the client to support PeerCache, is there (or will there be in the future) any way to 'opt out' of using it? I also have privacy/'logging all download request' concerns...

5. If a remote ISP is using PeerCache, can that benefit my client? i.e. If I try and connect to a client who is on a PeerCache ISP, will my client use his PeerCache? I assume not...


A quick search turned up some ISP's in Europe are using this, but not very many so far...

http://www.theregist...ing_your_kazaa/

http://networks.sili...com/broadband/0,39...10005229,00.htm

Good work guys!

This post has been edited by BillyGates: 03 July 2004 - 08:12 AM

[Some Support]

Quote

1. Is there any way to tell if PeerCache is being used?

Yes eMule will tell you if your ISP supports PeerCache when starting up and it is found. You can see when you upload to a client which is using PeerCache in your uploadwindow.

Quote

2. If it's really a transparent proxy, what had to be done in eMule to support it? i.e. Transparent http web caches don't require specific changes to the web browser.

eMule had to implement an according protocol to support PC.

Quote

3. I -assume- you need to be running on the standard eMule ports to support this?

No, you can use any port you want

Quote

4. If a change had to be made to the client to support PeerCache, is there (or will there be in the future) any way to 'opt out' of using it? I also have privacy/'logging all download request' concerns...

You can turn off downloading from the cache in the extended preferences. Uploading is always enabled - it is no difference then uploading to another client itself tho, except that you use another IP.

Quote

5. If a remote ISP is using PeerCache, can that benefit my client? i.e. If I try and connect to a client who is on a PeerCache ISP, will my client use his PeerCache? I assume not...

Yes your client will use his PeerCache to upload data to, which he downloads. Chances are, that you do not need to upload data at all because it is a cache-hit. You still get credits for data (not) transfered due to cache hit, so there is a small advantage for you.

[Superlexx]

Some Support, on Jul 3 2004, 10:27 AM, said:

You still get credits for data (not) transfered due to cache hit, so there is a small advantage for you.

Now how fair is that? You get credits without uploading a thing?

[slowsilver]

Superlexx, on Jul 3 2004, 02:07 PM, said:

Now how fair is that? You get credits without uploading a thing?

Why not? The request was directed at you, the upload started when the client reached a position in your queue, chances are it was specifically you who uploaded the chunk to start with and FWIW you may be the owner of the proxy that runs PeerCache.

For all purposes you are a valid (and hopefully) fast source for that chunk: more exactly those who request it from you will be served. And then, you deserve some credit for choosing an ISP that runs PeerCache.

=== edit ===

Damn typos.

This post has been edited by slowsilver: 03 July 2004 - 01:02 PM

[Superlexx]

slowsilver, on Jul 3 2004, 03:02 PM, said:

And then, you deserve some credit for choosing an ISP that runs PeerCache.

Uploaders ISP only matters if the outgoing traffic is cached too, which I am not sure of.

And, exploit nr. 1: deactivate download limit, set upload to 1kB/s, upload only 1 kB per session. People with PC-ISPs will download their stuff from the cache but will give you credits. You will earn much more credits than any 0.43a eMule because as far as I can see they don't give an immidiate slot to a client from PC-enabled ISP to check if the data is cached.

[JayC30]

I am ging to ask a basic question. Will this affect users of older versions of eMule adversely?

Quote

QUOTE 
4. If a change had to be made to the client to support PeerCache, is there (or will there be in the future) any way to 'opt out' of using it? I also have privacy/'logging all download request' concerns...


You can turn off downloading from the cache in the extended preferences. Uploading is always enabled - it is no difference then uploading to another client itself tho, except that you use another IP

What happens if PeerCache is not available through your ISP? Would standard upload protocols take over and direct transfer to another client?

It is a tad confusing to those of us that have no idea what this is, or don't understand it even after going to the website.

[BillyGates]

Thanks for the answers SomeSupport!

Unfortunately this opens up way more questions for me!

The facts that your eMule client knows it's talking to a PeerCache, and it supports any TCP port, means I wouldn't call this a 'transparent cache', as the client is aware of it. And is more like a 'Proxy Cache', if I was to relate it to Transparent and Proxy web caches. Where if you're running eMule and your eMule is aware of a local PeerCache, it will try and use the PeerCache first for uploading or downloading, then on a Cache miss it will connect directly to the end clients?

For remote ISP PeerCache's, I assume there's a new 'handshake' conversation with eMule peers in which you ask your peer if it has a PeerCache, and if so you will always try and contact the remote PeerCache first for any uploading or downloading with that peer.

If you have a local PeerCache, likewise I assume you'll contact your local PeerCache to see if you can download any chunks or if you need to upload any chunks that are already on the cache.

Also, since PeerCache supports any TCP ports, I have to believe there's a list of PeerCaches or something in eMule now to direct it find the PeerCaches. If I'm on a non-standard port, and the remote person I'm connecting to is on a non-standard port, there's no way a transparent cacheing system could know about us unless our eMules are trying to register with some sort of centralized PeerCache directory.

For those interested in how things work... if there's any link to the description of the communication that goes on with PeerCache it would be appreciated.

If must say I'm very happy this is not a transparent cache and is disableable ... but as a whole, it sounds like it could really improve speeds for everyone on the eMule/eDK network!

Thanks!

This post has been edited by BillyGates: 03 July 2004 - 08:22 PM

[donq]

About transparency - in current context this means the following:

PeerCache (PC) doesn't act as active ed2k network client/server. PC caches parts of files, which could be obtained from same clients without using PC. PC doesn't store any data to make it accessible for more clients, neither doesn't PC allow downloading data, not present on uploading side. Shortly - PC does not share files.

PC transparency doesn't mean silently intercepting ed2k connections - due to ed2k protocol statefulness this would be almost impossible.

Like BillyGates said, this behavior is not similar to HTTP cache transparency, where connections are intercepted on-the-fly without direct connecting to cache.

[leexgx]

this is probly why edonkey has been going fast with been able to download of peercache and able to download from an http link (+horda)

the only thing we need now is the upload slots sorting out and SUWQT then emule be king

[Sliderwkw]

Guys how do you know if the peercache works on emule v4.3a?

[prototyp]

Quote

Guys how do you know if the peercache works on emule v4.3a?

by the start, in the log (or verbose)

[Sliderwkw]

MIne doesn't say anything abount peercache at the start. I checked the verbose, it has last failed search is too near. Does that mean mine isp doesn't support it?

This post has been edited by Sliderwkw: 04 July 2004 - 10:40 AM

[BigRedBrent]

slowsilver, on Jul 3 2004, 01:02 PM, said:

the upload started when the client reached a position in your queue

Why would they need to wait in que to start downloading the part that is cached if you are not going to directly upload it to them and they can just start downloading it from the peer cache?

Wouldn't it be better if you received the peer cache info when you first connect to the source so you can just go ahead and start downloading it.

I could be wrong about how this peer cache worked but I would assume that it does not require you to directly send the data to users once you have already cached it and they are able to download directly from the cache. I would also assume that more than one person at a time can download from the same cached source at the same time. This would allow anyone who can access the peer cache where you cached the file part to start downloading that part without waiting in the que.

I would also like to know if you have downloaded a cached file part if you then will start sharing the address to the cache to users who connect to you.

[Sliderwkw]

waz the point of discussing the protocol if it does not work

[Superlexx]

lol can you prove that the protocol does not work? I am currently working on a diagram that illustrates the PC protocol.

As far as I can see, there is no active PC source distribution. This would need a lot of connections when PC becomes common. I have an idea how to dramatically reduce this number for WebCache sources (it would work for the PC sources too).

[BigRedBrent]

Well I hear it works on a few European ISP's and I guess they are hoping the ability to save money will motivate the rest.

[Sliderwkw]

Superlexx, on Jul 4 2004, 11:22 AM, said:

lol can you prove that the protocol does not work? I am currently working on a diagram that illustrates the PC protocol.

As far as I can see, there is no active PC source distribution. This would need a lot of connections when PC becomes common. I have an idea how to dramatically reduce this number for WebCache sources (it would work for the PC sources too).

sorry , I meant that peercache doesn't work on my isp relax brother

[aelfwyne]

I'm pretty sure my ISP (big national telco here in the US, SBC/Yahoo) won't use anything like peercache until if/when it becomes accepted and pretty standard, and then they probably still won't .... And no, peercache is not enabled for me..

But... just trying to decipher the logs here:

7/6/2004 12:01:11 AM: My public IP Address is: 70.240.xxx.xxx
7/6/2004 12:01:11 AM: PeerCache: Found my Hostname: adsl-70-240-xxx-xxx.dsl.hstntx.swbell.net, continue search
7/6/2004 12:01:11 AM: DNS Lookup for PC, state 3, failed - PC not found yet
7/6/2004 12:01:11 AM: DNS Lookup for PC, state 3, failed - PC not found yet
7/6/2004 12:01:11 AM: DNS Lookup for PC, state 3, failed - PC not found yet
7/6/2004 12:01:12 AM: Found PeerCache IP: 204.251.10.205
7/6/2004 12:01:14 AM: PeerCache: Failed to retrieve .p2pinfo file on Port 4662
7/6/2004 12:01:15 AM: PeerCache: Failed to retrieve .p2pinfo file on Port 1214
7/6/2004 12:01:15 AM: PeerCache: Unused content tag for validity check:  <META http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
7/6/2004 12:01:15 AM: PeerCache: Unused content tag for validity check:  <META http-equiv="Refresh" content="0;url=http://parked.directnic.com/">
7/6/2004 12:01:15 AM: PeerCache: Unused content tag for validity check:  <!-- tigershark/3.0.113 at <A href="http://www.directnic.com/">dn5.directnic.com</A> -->
7/6/2004 12:01:15 AM: PeerCache: CacheIP check failed.
7/6/2004 12:01:15 AM: PeerCache: ClientIPRange check failed. my IP: 70.240.xxx.xxx

I've blotted my own IP address, but you can see that it does seem to have found an address for peercache, or so it seems. Then it shows that there's no response, and basically apparently that address is a "parked domain"... in fact, directnic.com is nowhere near my ISP on a traceroute - it goes through numerous other links outside of swbell and sbcglobal's domains.

So why is it picking up what appears to be pretty much some random IP address and looking for peercache there?

[Some Support]

This is a bug, it shouldn't look up this domain. You ISP doesn't supports PC. Will be fixed in the next version.

[BigRedBrent]

Some Support, on Jul 6 2004, 05:53 AM, said:

This is a bug, it shouldn't look up this domain. You ISP doesn't supports PC. Will be fixed in the next version.

As far as I know the hot fix for this is out now in 0.43b.