Active Network

• A Survey of Active Network Research

• Direction in Active Networks

• Protocol Boosters : Applying Programmability to Network Interfaces

指導老師 - 鍾添曜06-01-1999

871775 顧凌峰 / 871772 陳桂慧

Survey of Active network

• Active networks are a novel approach to network architecture in which – The switches and the routers of the network perform

customized computations on messages flowing through them .

• Take a look at fig.1– Nodes can perform computation on ,and modify,the packet

content.

– This process can be customized on a per-user or per-application basis.

IndexThe emergence of Active network……………………………………. 3

Accelerating Infrastructure innovation……………………………….. 4

Enable new application……………………………………………….. 5

A Framework active network research……………………………….. 6

Architecture overview………………………………………………… 9

Composite network services………………………………………….. 13

Application…………………………………………………………… 16

Protocol booster………………………………………………………. 17

FZC booster implementation …………………………………………19

Conclusion……………………………………………………………. 20

Current research………………………………………………………. 21

§The Emergence of Active Network

The concept from discussion of within the broad Defense Advanced Research Project agency (DARPA) research community In1994~1995.

Several problem occur with today`s network :

—Difficulty with integrate new technology into shared infrastructure

—Poor performance due to redundant operation at several protocol layer

—Difficulty accommodating new services in present architecture model

Several strategies emerged to address these issue called active network

§Accelerating Infrastructure innovation

Lead user : some new services

Firewall,Web proxy,Nomadic router ,Transport gateway

Today,the path from from prototype demonstration to large-scale deployment takes about ten years.

However,Active node can execute many different programs

—In the past,the networking industry devoted to bundle Hardware and Software together,and active network change this innovation.

—Network programming abstraction provides a powerful platform for user-driven customization of the infrastructure(user could program).

§Enable New Application

Merging and Distribution of information

Merging data can reduce the bandwidth ;user-specific multicast reduce the load on the sensor and network backbone (FIG.2)

User-aware network protection

Active network may admit the design of an integrated mechanism

this eliminate multiple authentication independently of each layer.

Active network management

§A Framework for Active Network Research

Programmable switch-a discrete approach

— User first inject their custom processing routines into the required routers(programmable node).

— When a packet arrive a node ,they examine its header ,and the appropriate program is dispatched to operate on its contents.

Capsules - An Integrated Approach(every message is a program )

—First identifies capsule boundaries,possibly using framing scheme —The capsule`s content are then dispatched to a transient execution environment —with some built-in primitives which provide to access resource external to transient execution

Architecture

• Common base functionality of node architecture– how packets are processed

– what resource are available at that node

– how they are assessed

• Execution Environment (EE)• Node Operating System (NodeOS)• Fig 1, Fig 2.

The NodeOS implements communication channel, over which EEs send and

receive packet.

EEs = “shell” program in a general-purpose computing system, providing an interface through which end-to-end

network services are provided to user.

The request is accompanied by an identifier for the principal in whose

behalf the request is made.

Schedule only for computation

Schedule for both computation and

transmission

controlled by a pattern specified by the EE when

it creates the channel.

Architecture(cont’)

• Active Network Encapsulation Protocol (ANEP)– The ANEP header includes a type identifier field; types

ID are assigned to specific EEs.

• Interfaces and Standardization– EE-NodeOS interface need not be identical from node to

node; all that is required is for each node to provide a standard set of basic services to EEs.

– User-EE interface mainly involve encodings that must be understood by both the end user and the NodeOS

Composite Network Services

• Goal of active networks– to ease the deployment of new services.

• An important support feature of a network API– ability to compose services from building blocks.

– the building blocks for network services as components.

– A network API contains a composition mechanism used to create a composite service from component.

Composition Mechanisms• Choice from a set of options

– selects a predefined computation at the network node.

• Turing-complete programming language– components can be install in the active node as Java

subroutines.

• Special-purpose language for composition– a restricted language specifically design for services

creation can be used to compose network services.

• Event-based framework– dynamic behavior can be incorporated into composition

by structuring the composition as an event-driven computation and ”binding” code modules to specific.

Composition Mechanisms(cont’)

• Service composition in LIANE,

(language- independent active network environment)

– underlying program

– injected program used to customize the underlying program

Application - Caching

• Static hierarchy– administrative burden

– limiting the ability to react to dynamic conditions.

• Reduce network traffic and response time.– where to locate object.

– how to forward request between caches.

Protocol booster ——

Applying programmability to network infrastructure

— It allows dynamic and efficient protocol customization to heterogeneous environments.

§The two limitations of TCP/IP

—They evolve more slowly than the changes in networking tech and application requirements.

— They trade some loss for their ability to handle in efficiency with the increased heterogeneity.

§ Why protocol booster

— It is the need for protocol adaptation and programmability,then generate protocol booster .

— For example,when on a LAN the protocol would adjust itself to give performance similar to that of a specialized LAN protocol.

Properties for Fig.1

using booster nesting

host X,Y don`t know about the existence of booster

multiple element booster

single booster can monitor protocol messages to and from message stream

ex.hide retransmission in a application required low-lantency

§Practical Example the FZC(forward EraZure correction)booster

It is a multiple element booster

It reduces the effective packet loss rate on noisy link,by FEC.

Fig.2

at transmitter add h1 parity packets ,and the receiver recover from

up to h1 packets erasures.

§ Conclusion

—Active network involve the synthesis and extension of programming language ,operating systems ,and networking expertise

— Protocol booster are a ideal application for an on-the-fly(dynamic) programmable network infrastructure

— In place of protocol stack ,application may use protocol components that can be specialized and composed to perform application-specific function

§Current research

—Massachusetts Institute of Technology(M.I.T)

Prototyping an architecture based on the capsule approach

—University of Pennsylvania

Developing a programmable switch approach that allows digitally signed type -checked modules to be loaded into the nodes

— Bell communication research

several aspects of the Penn design will be studied jointly with Bell core ,but using different infrastructure(OPCV2)

— Columbia university (it`s a agent)

“Net script” provide a mean to script the processing of packet stream

— Carnegie Mellon University (CMU)

developing resource management in support of application aware network