A Survey of Active Network Research

By:Tennehouse,Smith,Sincoskie,Wettherall,Minden

Presented By:Prashant, Ravikiran, Ashutosh

Objective•Introduction to Active Networks

- Motivation

- Aims

- Impact

•How to Implement Active Network

- Discrete Approach

- Integrated Approach

• Snapshot of current research

Active Network

Active network is an approach to network architecture in which the nodes of the network perform customized computations on the message flowing through them.

This concept permit applications to inject programs into the nodes of network.

Example :

1) One can load “trace” program to routers and program will be executed then and there when his packets are processed at that router(active).

Origin of Active Networks

It is the result of discussion within Defense Advance Research Projects Agency(DARPA) research community in 1994-95.

Motivation for Active Network• Difficulty of Integrating new technologies and

Standards.

• Poor performance because of redundant operations at several protocol layers.

• Problems in accommodating new services.

Existing Applications :

Many application use a sort of Active Network approach to handle current network related problems.

e.g.

•Firewall

•Web Proxies

•Nomadic Routers

•Application Services

Technology Advancement:

Recent advances in programming languages, compiler, and operating systems provides the safe and efficient execution of mobile programs.

Aim of Active Network:• Programmable nodes.

•Standard execution environment

• No Standard functions

Impact of Active NetworkingAccelerating infrastructure innovation

A new technology from prototype demonstration to large scale deployment takes about 10 years.Current backlog are:

. RSVP

. IPv6

. Multicast services

But Active networks eliminate the need for formal standardization.

Enabling new technologies

• Merging and Distribution of information

N sources sending signals to M destinations.

End nodes does all of its mixing,work

With Active networks, work

NM N

•Stock Quotes:

At present generally web caches do not cache the stock quotes because of its dynamic nature and even if it caches, the granularity of the object(entire web page) is inappropriate.

Active networks can cache quotes at network nodes using a per-stock name granularity.So, all client request can be fulfilled with specified degree of currency

• Online Auctions:

Servers responds to the current price requests but due to delay in the network the information carried by the packet may become outdated when it reach the client. Then, the auction server will receive bids that are too low and need to be rejected and this imposes overhead on the heavily busy server.

With active networks these bids can be filtered out before they reach the server. So the response time of bid rejection to the client and server processing overhead is reduced.

User Aware Network ProtectionActive network may admit the design of integrated mechanism to govern network resources and information flowing through them. So, program in Network security policy for the network on a per-user or per-use basis is allowed.

Active Network ManagementActive technologies could be used to implement sophisticated approaches to do network monitoring and uninteresting event filtering.

Rethinking Performance•Despite increasing the amount of processing at nodes, Active network will lead to improved performance.

i.e. Reduced throughput and increasing latency appear to degrade the performance, they may actually improve performance because of reduce demand of bandwidth at endpoints, network congestion.

•Network performance is not always positively related to the Application performance.

Caching in the memory as in the stock quote example can reduce latency of data access when the server is busy.

When network nodes in the auction application reject low bids, they inform the “losing” end nodes than could the overloaded (and farther away) server.

Performance also depends on the location where the active node is deployed.

•In the sensor fusion example, the greatest decrease in bandwidth utilization occurs when the splitting of multicast streams is performed as late as possible and mixing as early as possible

•In stock quote example, it is important to place the caches where they will serve the large number of client request.

•In online auction,filter should be far enough from the server to turn back low bids asap, but close enough to the server to get proper up-to date price.

Approaches to implement the Active NetworkProgrammable Switches- A discrete approach:

User would first inject their custom processing routines into the required routers. Then they would send there packets through such “programmable” nodes. When the packet arrives at the node its header is examined and the appropriate program is executed.

Capsules-An Integrated Approach:

In this approach ‘program’ is integrated in the packet along with the data. When these capsule arrive at the active nodes then it interprets the program and sends the embedded data depending on its interpretation.

This is same to the Postscript code, where actual data is embedded in program fragments that the printer understands.

Active IP:

Active option is in the payload of the packet, the legacy router can route the packet transparently to active node where the ACTIVE Option code will be evaluated and executed.

Common Programming modelProgram Encoding:Our objectives of program encoding are that they support

•Mobility- transfer programs and to execute them on different platforms

•Safety-restrict resources that program can access

•Efficiency-enabling above without compromising network performance.

Mobility can be achieved at different level of program representation.

•Source level- Use of scripting language say TCL.

•Intermediate level- Use of Byte code virtual instruction say in JAVA.

•Object level- Use binary formats as in Omniware.

Common Primitives:

The services built into each node might include several categories of operations: primitives that provide access to the node’s environment (e.g node address, time of day and so on).

Node resources and their allocation:

There must be a common model of node resources like bandwidth, processing capacity and the means by which policies governing their allocation are communicated.Safe resource allocation is a considerable research area.

Current researchThe goal of research is to develop:

•Languages and compiler for “active” software.

•Platforms for deploying Active Network nodes.

•Architecture for capsule and programmable switches

•Safe resource allocation schemes.

•Massachusetts Institute of Technology-This team is prototyping an architecture based on the capsule approach and studying “active storage”, NACK fusion and filtering.Demand loading is also a concern.

•University of Pennsylvania-The “Switch Ware” project proposes a switch, which has a programmable element performing switching function.

•Bell Communication Research- Several aspects of the Penn design will be studied jointly with Bellcore using different infrastructure OPCV2.

•Columbia University-Netscript architecture which uses encapsulation approach along with scripting language is developed.

•Carnegie Mellon University-It is developing resource management mechanism in support of “application aware” networks.

•Other Sites-University of Arizona, Georgia institute of technology, University of Kansas, BBN, University of Cincinnati.