Slashdot Mirror
Enhancement To P2P Cuts Network Costs
psycho12345 sends in an article in News.com on a study, sponsored by Verizon and Yale, finding that if P2P software is written more 'intelligently' (by localizing requests), the effect of bandwidth hogging is vastly reduced. According to the study, redoing the P2P into what they call P4P can reduce the number of 'hops' by an average of 400%. With localized P4P, less of the sharing occurs over large distances, instead making requests of nearby clients (geographically). The NYTimes covers the development from the practical standpoint of Verizon's agreement with P2P company Pando Networks, which will be involved in distributing NBC television shows next month. So the network efficiencies will accrue to legal P2P content, not to downloads from The Pirate Bay.
How do you reduce the number of 'hops' by an average of 400%? Negative number of hops? Also, FP.
God, root, what is difference ?
Network topology isn't & can't be a secret...
[Fuck Beta]
o0t!
Well, strictly speaking, incrementing the number would result in P3P, not P4P. Just as P2P means "Peer to Peer", P4P could be interpreted as "Peer for Peer", justifying the numeral.
____
~ |rip/\/\aster /\/\onkey
... or is it encouraging to see network providers taking a stance other than p2p is bad? This looks good - kind of like "p2p isn't going away, so as long as we have to live with it, let's try to make the best of it"
I'm a student. I write iPhone apps.
Reducing hops by 400%, eh? That's a nice trick. Can we reduce bandwidth usage by the same amount? I wouldn't mind some free bandwidth.
I honestly can't figure out where "reduce by 400%" came from. They say the average hops were reduced from 5.5 hops to 0.89 hops, which is either 84% if you're not an idiot or 616% if you are. So I'm really quite confused here. Go figure.
Breaking Into the Industry - A development log about starting a game studio.
While I understand what they're saying here, and I understand the surface intent of the message, I get this feeling that there is some sort of devious underlying motive here. Or it could just be that I have my Slashd^H^H^H^Htinfoil hat on a bit too tight.
That works out to an average 84% reduction.
Personally I'm waiting for the next binary progression, Peer Ate Peer, or P8P. I'm not sure what it will do, but I'll bring popcorn to watch...
You are in a maze of twisted little posts, all alike.
http://hosted.ap.org/dynamic/stories/P/P2P_VERIZON?SITE=MITRA&SECTION=HOME&TEMPLATE=DEFAULT
For this reason, Verizon doesn't suck for broadband uses. In my area, I have Verizon DSL (they haven't given us Fios yet, but they ran the fiber cables a few years back) and I don't have any port blocking (that's right folks, I can send email to ANY server), and they don't limit P2P or Bittorrent (My downloads are fast and fresh). And they haven't turned records over to the government (or at least not reportedly, yet). So far, in the category of BIG ISPs Comcast vs Verizon, Verizon is being the underdog. Which is funny, because start arguing cell phone policies and prices, and watch the argument change completely.
Belief? Hope? Preference?The Existential Vortex
And let's face it, people, the next protocol will have to have a few features to be accepted, and having "local peers" isn't on the top of the list.
What the list includes? Easy:
1. Encryption
2. Onion routing
For very obvious reasons. And neither of them decreases bandwidth used. Quite the opposite.
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
less of the sharing occurs over large distances, instead making requests of nearby clients (geographically).
How about a BitTorrent client that gives preference to peers on the *same ISP*?
Yeah, less hops and all is great, but if an ISP can keep from having to hand off packets to a backbone, they'll save money and perhaps all the hue and cry over P2P will die down some. I'm sure Comcast would rather contract with UUnet to handle half of the current traffic destined for other ISPs than they do now.
Sort of a 'be nice to the ISPs and they'll be nicer to the users' scenario.
It would have made Internet broadcasting much more efficient, but it never took off. Why? Because providers never wanted to turn it on, fearing their tubes would get filled with video. So what happened? People broadcast videos anyhow, they just don't use the more efficient Mbone multicasting method.
Furthermore, when I download a video via Bittorrent, there are usually only a few people, whether they have a complete seed or not, who are sending out data. So how local they are doesn't matter. If there are more people connected, usually most people are sending data out at less than 10K, while there is one (or maybe 2) people sending data out at anywhere from 10K to 200K. So usually I wanted to be hooked to them, no matter where they are - I am getting data from them at many multiples of the average person.
I care about speed, not locality. The whole point of the Internet and World Wide Web is locality doesn't matter. Speed is what matters to me. For Verizon however, they would prefer most traffic goes over their own network - that way they don't have to worry about exchanging traffic with other providers and so forth. Another thing is - there is tons of fiber crisscrossing the country and world, we have plenty of inter-LATA bandwidth, the whole problem is with bandwidth from the home to the local Central Office. In a lot of countries, natural monopolies are controlled by the government - I always hear about how inefficient that would be and how backwards it would be, but here we have the "last mile" controlled by monopolies and they have been giving us decades-old technology for decades. In fact, the little attacks by the government have been rolled back, in a reversal of the Bell breakup, AT&T now owns a lot of last mile in this country. Hey, it's a safe monopoly that the capitalists, I mean, shareholders, I mean, investors can get nice fat dividends from in stead of re-investing in bleeding edge capital equipment, so why give people a fast connection to their homes? Better to spend money on lawyers fighting public wifi and the like, or commissars and think tanks to brag about how efficient capitalism is in the US of A in 2008.
Some of us working in the bleeding edge of p2p have been playing with these ideas for years to improve performance (I'm building open VR/MMO over P2P), here's the basics...
Most true p2p systems use something called a Distributed Hash Table (DHT) to store and search for metadata such as file location and file metadata. Examples are Pastry, Chord, and (my favorite) Kademlia. These systems index data by ids which are generally a hash (MD5 or SHA1) of the data.
Without going into the details of the algorithms, the search process exploits the topology of the DHT, which becomes something called an "overlay network". This lets you efficiently search millions of nodes for the IDs you're interested in in seconds, but it doesn't guarantee the nodes you find will be anywhere near you in physical or network topology space.
The trick some of us are playing with is including topology data in our DHT structure and/or search, to weigh the search to nodes which happen to be close in network topology space.
What they are likely doing is something along these lines, since they have the real topology instead of what we can map using tools like tracert.
If they really want to help p2p, then they would expose this topology information to us p2p developers, and let us use it to make all our applications better. What they're likely planning is pushing their own p2p, which will be faster and less stressful on their internal network (by avoiding peering point traversal at all costs, which is when bandwidth actually costs THEM). The problem is their p2p will likely include other less desired features, like RIAA/MPAA friendly logging and DRM, and then they'll have a plausible reason to start degrading other p2p systems which aren't as friendly by their metrics, such as distributing content they don't control or can't monetize... Then again, maybe I'm just a cynic...
Even better, change the letter too. I'm waiting for B4B: Beer 4 Beer.
mmmm... Beer.
Jiggity
This has been my main criticism of "p2p" user-level networking for years. The selection of "peers" has no clue about network structure. The routing performance is just awful. Finally, someone is doing something about it.
One problem is that, from an endpoint perspective, it's tough to extract network topology and bandwidth. Hop count is only moderately useful. But there are a few tricks one can use.
There are several basic numbers of interest - bandwidth, delay ("lag"), hops,"bottleneck points" and commercial boundary crossings. Each of these can be measured.
Delay, or lag, is the easiest to measure. A few pings and you've got it.
With bittorrent, you're not committed to staying with a peer for an entire download. So you can observe the bandwidth of the peers you're talking to and preferentially use the higher bandwidth ones. You really have to transmit for a while to get a solid bandwidth number, especially since Comcast introduced "Boost" quality of service, which increases bandwidth allocation for a few seconds on demand, then reduces it.
If you do a traceroute, you'll usually observe that many hops show low lag (those are usually hops within a single data center) while others show higher lag. The number of high-lag hops is the number of "bottleneck points" in the path.
Commercial boundary crossings occur then packets cross from one ISP to another at a peering point. Users don't notice this much, but carriers are very interested in minimizing that traffic. Converting IP addresses to autonomous system numbers, as someone mentioned, can tell you when you're crossing a boundary.
So it's possible to collect enough data to do intelligent routing without much help from the network provider. What to do with that data is a separate question, but a solveable one.
How do you possibly get an average of LESS than one hop, unless you're getting the file from yourself?
Usually when people are talking about hops, they are referring to routers. The only way you would not go through a router is if you and the source were in the same LAN. If you get an IP address from your ISP and it is one of the private ones (ie. 192.168.0.0/16) then you will likely have to go through a NAT machine before you will be able to see anyone. If your IP address is a publicly route-able address then it will most likely be in a LAN with your neighbors. There are ways to explain why 0.89 would be possible.
Claiming 0.89 hops is more interesting because they are claiming that others in your network are already downloading or have downloaded the file. It seems unlikely that someone in my own network would be downloading the same file, or would be seeding the file that I wanted. It seems to me that the most likely way that they could get 0.89 hops is by limiting the number of actual files distributed by their P4P software. Maybe they just had 10+ test files that just happened to be all over the network already.
This is true, but if 80% of your P2P bandwidth is going within your ISP's local network, then only 20% is going out their interconnect links, which is better than 95% that would happen normally. And by better, I mean better for the ISP. If you have less traffic going out their interconnect links, that is more available bandwidth for other non-P2P traffic. I think their goal is to allow P2P to happen with having the minimal impact on the non-P2P customers.
WTB [sig], PST!!!