Enabling Global Multimedia Distributed Services based on Hierarchical DHT Overlay Networks

1Isaias Martinez-Yelmo

Enabling Global Multimedia Distributed Services

based on Hierarchical DHT Overlay Networks

Isaias Martinez-Yelmo, Alex Bikfalvi, Carmen Guerrero, Ruben Cuevas, Andreas Mauthe

[email protected]

2Enabling Global Multimedia Distributed ServicesBased on Hierarchical DHT Overlay Networks


Overview

• Introduction• P2PSIP• Hierarchical-ID• Service Mapping• Routing on Hierarchical DHT• Analytical Performance• Validation via Simulation• Conclusions• Future Work



Introduction

• Objective

• P2PSIP is an excellent candidate for Multimedia Distributed Services– But, Global connectivity between different

Distributed Services has yet not been considered• Our proposal tries to overcome this missing feature

– Enabling Global Multimedia Distributed Services based on Hierarchical DHT Overlay Networks



P2PSIP – What is P2PSIP?

• P2PSIP is an IETF Working Group• Objectives

– To provide a protocol that allows Distributed Multimedia Services

• The motivation is to provide Skype-like services based on an open standard

– User friendly• NAT Traversal based on ICE protocol

• Functionality on Multimedia Services– Distributed replacement of SIP entities

• Proxys• Registrars



P2PSIP – Features

• RELOAD is the P2PSIP protocol– It is payload can support any type of p2p network

• Specially DHT networks (Chord, Kademlia, …)– An Overlay-ID exist to differentiate the difference instances

• It supports all the needed primitives: Join, Fetch, …• It can also support NAT traversal based on ICE

– What is not being defined?• The type of information stored on the p2p network• How the information is stored on the p2p network

– It depends on the application

• Resource/Service Mapping



P2PSIP - Limitation

Domain.a

Domain.b

Domain.c

Domain.d

Interconnection Overlay



Hierarchical-ID

• Prefix-ID– It is only used in the Interconnection Overlay– Routing at Super-peer level

• Suffix-ID– It is only used internally within each P2PSIP domain– Routing at Peer level

Prefix-ID

(n bits)

Suffix-ID

(m bits)

Enabling Global Multimedia Distributed ServicesBased on Hierarchical DHT Overlay Networks


Service Mapping

• Is not defined by P2PSIP WG

• Depends on the application

• Should be based on URI’s

• A simple example– URI: [email protected]– Prefix-ID = hash(example.com)– Suffix-ID= hash([email protected])– More complex mappings could be used



Routing on Hierarchical DHT’sdomain.a domain.bInterconnection Overlay

Store(hash(domain.a), IP, Port,hasha)Response

Store(hasha([email protected]), IP, Port)Response Fetch([email protected])

Fetch(hash(domain.a)Response(hash(domain.a), IP, Port, hasha)

Fetch(hasha([email protected]))

Fetch(hasha([email protected]))

Response(hasha([email protected]), IP, Port)

Response(hasha([email protected]), IP, Port)

Response([email protected],IP, Port)

Legacy SIP exchange: INVITE, ...

Superpeers

• If different hashes or mapping functions are used in each overlay– Interconnection

– Own domain

• A direct response cannot be used

mauthe

what do you mean by this? Which paper???



Analytical Performance

• General Formulation for Routing Performance:

• After simplifications:

• In Kademlia:

K

ijjjjijiiiii KCMDMDRP

,1

1

cKMRPRP Bi 2log1

Intra-cluster Inter-cluster

P2PSIP domain

KCK

KMDRPRP i

1

1

Interconnection Overlay



Validation via Simulation

• Simulator: PeerFactSim.Kom based on Java– Simple Network Model– Hierarchical Kademlia implementation

• It is based on its Kademlia implementation– K=20, Alpha=1, B=2b=2

– Domains: 5, 10, 20– Peers: 10-1000

• Up to 10,000 peers• 64-bit Intel Architecture with 8GB RAM (2 weeks)• 95% Confidence Intervals have been calculated

– The error is smaller than a 5%



Routing Performancefor Value Lookups



Routing Performance for intra--domain for Node and Value lookups



Worst Case Routing Performancefor Value Lookups



Routing State for intra-domain Routing Tables



Conclusions

• We purpose a method for interconnecting P2PSIP domains– This mechanism enables Global Multimedia Distributed Services

based on Hierarchical DHT Overlay Networks– The main points are:

• The Hierarchical-ID• The Service and Resources Mapping• The signalling flow

– Based on the P2PSIP protocol (RELOAD)

– Peers do not increase its Routing State• Scalable Solution

– Only Super-Peers are highly loaded• Bandwidth

– The Routing Performance is not affected by this architecture



Future Work

• More detailed simulations– More domains– Churn Rate

• Modifications on the scenario– VoIP + Social/Community Networks

• More VoIP calls based on P2PSIP being done inside the Social/Community Network

– Global Routing Performance changes

• Super-peer management


Questions??


Isaias Martinez-Yelmo, Alex Bikfalvi,

Carmen Guerrero, Ruben Cuevas, Andreas Mauthe

[email protected]

Documents

Enabling Global Multimedia Distributed Services based on Hierarchical DHT Overlay Networks