PURSUIT Architecture

Mikko Särelä 19.9.2011

T-110.6210

2

Are the Fundamentals Still Valid?

Fundamentals of the Internet• Collaboration

– Reflected in forwarding and routing

• Cooperation– Reflected in trust among

participants• Endpoint-centric services

– (mail, FTP, even web)– Reflected in E2E principle

IP, full end-to-end reachability

Reality in the Internet Today• Phishing, spam, viruses

– There is no trust any more!• Current economics favor senders

– Receivers are forced to carry the cost of unwanted traffic

• Information-centric services– Do endpoints really matter?– Endpoint-centric services move

towards information retrieval through, e.g., CDNs

IP with middle boxes & significant decline in trust in the Internet

vs.

3

Observation: It's All About Information

Internet Today:• In 2006, the amount of digital information

created was 1.288 X 10^18 bits • 99% of Internet traffic is information dissemination & retrieval (Van Jacobson)• HTTP proxying, CDNs,

video streaming, …• Akamai’s CDN accounts for 15% of traffic • Between 2001 and 2010, information will increase 1million times from 1 petabyte (10^15) to 1 zettabyte (10^21)• Social networking is information-centric • Most solutions exist in silos• overlays over IP map

information networks onto endpoint networks

Internet Tomorrow:• Proliferation of dissemination & retrieval services, e.g.,• context-aware services & sensors• aggregated news delivery• augmented real life • Personal information tenfold in the next ten years (IBM, 2008)• Increase of personalized video services• e.g., YouTube, BBC iPlayer• Vision recognized by different initiatives & individuals• Internet of Things,

Van Jacobson, D. Reed• Lack of interworking of silo solutions will slow innovation and development speed

4

Hypothesis: Increased Information Requires Information-centric Network Approaches

Application developers care about information concepts– Creation of information topologies of various kinds

-> Endpoint-centric networking structures are inadequate– Topological network changes too slow in timescale– Topological network boundaries too restrictive– Topological network boundaries often not aligned with

information topologies– Overlaying possible but restricted in (developer) scalability

-> If it is all about information, why not route on information?

Why not?

• Why not route on information?

6

Main Design Principles

• Information is multi-hierarchically organised – Information semantics are constructed as

directed acyclic graphs (DAGs)

• Information scoping – Mechanisms are provided that allow for limiting

reachability of information to parties

• Scoped information neutrality – Within each information scope, data is only

delivered based on a given (rendezvous) identifier.

• The architecture is receiver-driven – No entity shall be delivered data unless it has

agreed to receive those beforehand.

Communication Model

InformationHierarchies

Informationreachability/scoping

7

Information Concepts

• Information– Smallest something

• Information collections– Sets of semantically similar information

• Information networks– Sets of information under some common

governance• Information producer

– Entity publishing information to a particular network

• Information consumer– Entity subscribing to information in a particular

network

8

Grouping Information Networks

9

Architectural processes• Rendezvous

– The process of resolving higher level identifiers to lower level identifiers within a given scope.

– Three simple cases: link-local, intra-domain, inter-domain• Topology management and formation

– Management of data delivery topologies and forwarding graphs

• Forwarding– Data delivery within a single administrative domain or

across multiple domains. – Temporal forwarding identifiers for each publisher and

subscriber are derived via the rendezvous and topology management processes

– Various routing and forwarding protocols can be used, for example a new protocol replacing IP or IP-based overlays

10

Subscriber Publisher

Forwardingedge nodes

Forwardingnode

Forwardingnode

Topology

ASRendezvous

Data Forwarding

Subscribe

Forwardingnode

Topology

ASRendezvous

Forwardingnode

Publish

Createdeliverypath

ConfigureForwardingpath

Architecture Overview

AS

Topology

12

Service Model and APIWe have considered four different classes of network services1. A low-level page model that exposes

network forwarding and rendezvous/topology formation functions

2. A mid-level memory object model

• Memory pages are mapped to publications

3. A mid-level channel model4. Various high-level service models

including shared state and document models

Low-level page API

Memory Object APIChannel API

Higher-level APIs

13

Node Architecture: Component Wheel• Components may be decoupled in space,

time, and context– Layerless protocol suite

• Applications may insert or request new components to the wheel at runtime– Implemented as helper functions

• The components are attached to the local blackboard (BB)– Components are attached to the local

blackboard, sharing publications, state– Pub/sub is used to signal changes to

blackboard state

14

Component Wheel InteractionsSubscriber Blackboard Caching Routing and forwarding Low-level Link

Register and subscribe notifications

Register and subscribe notifications

Subscribe

Notify first component in plan

Component done, no cache hit

Notify second component in plan

Access memory object

Forward subscription

Publication

Insert publication as memory object

Notify componen in plant

Notify that has been added to cache

Notify subscriber