Peer‐to‐peer Technologies
lightening the Internet
Kazuyuki Shudo, Ph.D.
shudo at utagoe.com

Director, CTO, Utagoe Inc.
February 19, 2008

A definition:

node may act as bothPeer‐to‐peer … Aa clientand a server• P2P content delivery • The subject of this P2P
industry association• P2P groupware– Ariel products, ifreestyle, Groove, …

• P2P bulletin board– Shingetsu, Winny 2, …

• P2P instant messenger• P2P phone•…

– Content:
Video, voice, music …,and other kinds of files.

Software package, patch andothers.

• Kinds of delivery tech
– Download– On‐demand streaming– (Live) streaming

P2P Content Delivery• Gathering technologies– Download– On‐demand streaming• Playing while downloading.

– Gather parts of contents replicated in advance.
– “Swarming”• Disseminating technologies

Audience

Source– (Live) streaming– Deliver content to massive number ofaudiences in a short time.
– “Application‐{level, layer} Multicast (ALM)”,“Overlay Multicast”, “Endsystem multicast(ESM)”
Massive audiences

Dissemination: ALM, OM, ESM

Tree‐based vs. Mesh‐based
SourceSource(2) DataData(1) RequestDeliverytree• Tree‐based–––––

Data flow along the delivery tree constructed
explicitly.
Push from the root toward leaves.
△ Requires quick repair in node failure○ Data reach all ends, with low latency.
Exploits broadband links.

• Mesh‐based––Keeps loose relationships with neighbors.
Pull data from neighbors.

––○ Robust to node failure by nature△ Delivery to ends not guaranteed.
To be compensated.
Exploits narrowband links.

–

Effects of P2P content delivery• Traffic reduction around the source– From 50 % to 9X %• Supports large number of audiences withthe same facilities.

– Massive content delivery with little
Following slides showresources• → “All publishing” society ?
• Examples• Others (left out here)– Swarming experiments– On‐demand delivery– (Live) streaming– Adaption to network situations• Who benefits from it?
– Fault tolerance– Lower management and operation cost

Swarming experiments• Conditions– On‐demand delivery with BitTorrent protocol– 24 peers on a LAN– Traffic reduction up to 80 % or more

From a talk by Aaron Colwell (RealNetworks, Inc.) in a panel in NOSSDAV 2007

On‐demand delivery• “39 % from origin server, 61 % from peers”– In case of an on‐demand video delivery service
in US in 2005.
• In case of pure on‐demand delivery,

Number of requests for eachcontent is long tail.
• Modeled with the Zipf’s law:
1st n, 2nd n/2, 3rd n/3, …

• Higher population yields higher
efficiency of P2P.
The opposite is also true.

• Being improved. (mentioned later)(Live) streaming• From 90 to 95 % of traffic reduced around the source– With Utagoe’s UG Live software

On Nov 26, 2007,“access talk-about live”

by J-Stream,
Castella (www.castella.jp),
and Utagoe

91-93 %
reduceduser-side
Over 90%
reduction
lastedserver-sideImplications of delivery‐stylein efficiency• (Pure) on‐demand delivery
Higher efficiency– A large number of examples• Channel

Scheduled playing
playing
Scheduledalong thethe timetable
timetablealong– JoostCommunications
Communications• Program‐directed delivery– Utagoe’s P2P IPTV, codenamed Lycaon.
TV experience + Net/Web strengths• (Live) streaming– BB Broadcast (Roxbeam (China) and TV Bank),
ShareCast2 (ANCL and bitmedia),
UG Live (Utagoe)

Menu
Menu

Who benefits from it?
• Audience– “It’s OK as long as I can see.”

Audience
receive• Content holder,
Delivery service provider– Benefits from traffic reduction

Deliverytechnologies
Content holder,
Delivery service
providersend• ISP, Carrier– ???

ISP, CarrierdeliverAmount of delivered data
does not depend
Server‐clientTransmit

ServerReceive

Peer (audience)Content delivery network
ServerRelay
server

Relay serverPeer (audience)

Peer‐to‐peer
ServerPeer

Peer (audience)

Amount of delivered data is constante.g. In case 1,000 nodes each receive 1 Mbps, 1,000 Mbps = 1 Gbps

• Note– CDN increases the amount by relay servers receiving but notplaying. Here ignored.
– Peer‐to‐peer increases the amount by control messages. It is
usually several percent.
• e.g. Peers communicate with a tracker in BitTorrent protocol.

Traffic reduction is …
• ISPs and carriers deliver the same amount ofdata, whichever delivery technology used.
• ”Traffic reduction” is an effect forcontent holders and delivery service providers.
• But, ISPs and carriers can benefit from it.
– Local production for local consumption

Local production
for local consumption• Peer‐to‐peer enables us to get contentsfrom ”near” peers.
– CDNs are still effective, but relay servers are
deployed at limited number of ISPs.
– Results:• Traffic to/from higher level of ISPs and transit fee reduced.
• Traffic on the Internet backbone and IXes reduced.
•…

• Most P2P software has such features:– A node selects peers to which it requests/sends dataaccording to throughput and/or latency.
• Utagoe’s UG Live: based on throughput– according to peer’s IP address and AS number.

Open problems• Are techniques to select “near” peers
consistent with ISPs and carriers’ interests?
– e.g. Throughput over the backbone can be higher than local one.
– Today, it is the only way for P2P software to measure throughput orlatency.
– ISPs and delivery service providers can cooperate with each other.
• e.g. CRNF’s activities: exploits address assignment information• e.g. Verizon and Pando’s activities in P4P WG in DCIA

• Is the currently deployed techniques effective?
– This P2P industry association is expected to show it.

• Do Internet operators still have difficulties in trafficengineering with peer‐to‐peer‐style all‐to‐all traffic?
– Discussion required.

Summary• Traffic reduction effect by peer‐to‐peer
technologies has been proven.

• ISPs and carriers can benefit from it.
– Local production for local consumption