VIRTUAL ACTIVE IP NODE FOR COLLABORATIVE

ENVIRONMENTS

Francisco Puentes, Víctor Carneiro

Information and Communication Technologies Departament University of A Coruña. Campus de Elviña S/N, 15071 - A

Coruña (Spain)

Keywords: Virtual active networks

Abstract: The present document describes the VAIN architecture (Virtu

al Active IP Node), which enables users to

deploy new network services based on virtual active networks, and how it solves the challenge of

segmenting the incoming traffic that crosses nodes towards the services, conserving the original objective of

independence of the protocol (Tennenhouse,1996). Our solution is based on using network expressions that

use all the semantic contained in each incoming packet, which does not need to know the inner structure of

the protocols. VAIN architecture has been development to response to challenges outlined by electronic

commerce, specifically those regarding to collaborative environments and marketplaces. To achieve this

objective we have considered the following goals: first, a three layer conceptualization; second, a

transparent implantation and its integration with existing infrastructures; and third, a strategy of network

traffic distribution based in all the information within the input packets, which is named “expressions based

distribution”.

1 INTRODUCTION

Since its proposal (Tennenhouse,1996), active

networks (networks formed by programmable

devices which are able to perform tasks on demand

over the traffic that crosses them) have turned into a

special research area with excellent works and

projects. Its success within the research community

is probably due to the fact that all involved

researchers understand this technology as a step

forward, opposite to traditional networks, since

nowadays active networks are able to perform

processes than traditional networks can not.

Traditional networks make a special emphasis in the

net

work structure and guarantee the information

delivery to the application which it serves in a

suitable time. Each intermediate device which

constitute these networks are specialized in

receiving packets of information, performing a

minimum set of tasks (typically over protocol

headers and therefore they are limited to the

structural aspects of communications ignoring its

meaning, that is, the packet content), computing next

hop or output’s interface and delivering packets

towards the wire. These networks are data

exchanged systems in which compute capacity relay

on the final elements of the network (client and

server on C/S architecture, for example).

Therefore, nowadays we say the sem

antics of the

communication is responsibility of the final

elements. Actually, communication does not add

meaning to the applications of which it is formed.

Active networks allow communications to be an

essen

tial part of the application’s total meaning,

being able to focus on the solution, that is, the

application, instead of on the transmission part of the

logic. The fact that between two distant points exist

one or more intermediate nodes with the capacity of

sharing logic have a direct consequence: The data

sender or receiver can share logic without need to

become a central server or a transmitter of the

information.

1.1 The needs of a virtual

architecture

Within active networks research virtual active

networks (VANs) are a special area (Gong Su,2001).

VANs are semantic networks which emphasize in

the abstraction of the communications, looking for

new architectures. These VANs have a clear

advantage over no-virtual active networks: they are

flexible and independent of the physical

infrastructure that supports them. However, any

change in the physical infrastructure, for example in

traditional networks, will remarkably affect its

Puentes F. and Carneiro V. (2004).

VIRTUAL ACTIVE IP NODE FOR COLLABORATIVE ENVIRONMENTS.

In Proceedings of the Sixth International Conference on Enterprise Information Systems, pages 49-54

DOI: 10.5220/0002602900490054

 SciTePress

design, due to the fact that the design will be highly

depending on addressing, naming and devices.

Hence, in this paper we will go a step forward,

asserting that the existence of a virtual layer, which

contents part of the meaning, not only make the

design more flexible regarding the changes on its

lower structure, but also it allows new ways to think

about communications.

1.2 Active networks and

collaborative commerce

From its beginning, electronic commerce has

evolved from the old EDI to the recent frameworks

like ebXML. The on-line collaboration has enriched

the old ideas giving rise to new concepts, like

collaborative commerce and distributed

marketplaces.

On the other hand, the technologies that give support

to these new forms of on-line work/commerce are

based in the well known concepts of the client/server

architecture through the interchange of messages. In

any case the present solutions only consider the

syntax of the communication, in which the final

nodes interpret the messages. That is, the semantic

of the communication – its meaning – is handled at

the final nodes of the communication, between the

different implied organizations.

We can define the collaborative commerce as the

commercial relations between organizations which

define common objectives and work in a

collaborative way, participating jointly in processes

of business previously decided (Puentes,2003).

Between the tasks to carry out in this context we can

mention the planning and estimations, the

management of the inventory, the management of

the supplying chain, the product design and

development, the manufacture, the logistics and

support to final clients.

We can divide these tasks in two categories: those

that compose the value chain (and therefore

susceptible to be managed by means of outsourcing -

justified via the theory of the integration cost) and

those that serve as support of the communication

with competitors, clients and suppliers (these two

last ones comprising of the supplying chain). The

solutions to automate the first of these categories are

the family of technologies associated with the

collaborative work, the second with e-marketplaces.

The collaboration in this last one is also susceptible

to be reached through technologies that are applied

to the first one (Tennenhouse,1996).

Current solutions to these needs are solved through

an external organization, the integration

intermediary, which manages, control and order the

interactions between its users. This highly

centralized approach is consequence of the

conceptualization of the solutions under a C/S

scheme. Active networks have the suitable features

to support new ways of on-line working and thus to

allow new forms of collaborative work. Virtual

active networks provide the necessary level of

abstraction to give an independent solution from the

lower platform and to allow the designer to focus

specifically in the business logic. We have

implanted VAIN (Virtual Active IP Network)

architecture, which proposes a virtual design

specially thought for the on-line collaboration with

the aim of implanting virtual collaboration processes

as marketplaces.

More specifically, active networks have a set of

features that make them appropriate to implant the

semantic of the business layer under a single

Virtual plane

Execution plane

Communication plane

Virtual active node

Active node

Network device

Emissar

Receptor

Final communication line

N:1 projection

(not easy)

0:1 projection

(

eas

Figure 1: Relations between planes

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solution: The nodes of an active network have the

features of flexibility and abstraction regarding their

behavior as elements of a communication network.

This necessity from adaptability to its environment

turns active nodes in a highly programmable element

since its behavior is susceptible to be modified

voluntarily; and abstraction, since the processes or

services are not known a priori will render to the

network to which it belongs.

On the other hand the forms to conceive the business

planes are directly related to the semantics of the

application in particular, which makes difficult to

elaborate a common technology for all casuistry.

The adaptation of the solution to the particular

semantics in each case, although viable, is not

optimal. Thanks to it the active networks can support

the implantation of solutions that have into account

not only the syntax of the logic of businesses, but

also their semantics on the own network, providing

different strategies and new and powerful designs.

1.3 Routing in active nodes

Active nodes are network devices that are able to

process packets of data crossing them. This capacity

of processing is dynamic, in such a form that the

incoming traffic can contain the code that the node

has to execute for a certain subgroup of packets that

it handles.

A very important stage of the routing in the

traditional devices is the selection of the following

jump which is done taking into account the

characteristics of the packet and the state of the same

device, which usually changes little between packet

and packet. We will talk in this document about this

selection as the distribution of the incoming traffic

in information flows, formed by individual packets

that fulfil a same criterion.

Basically, the proposed solutions until now presents

the feature of distributing the guest code data by

means of its inclusion in the processed traffic

(capsules, active packets) or by means of a dynamic

programming of the node (programmable nodes).

The execution of guest code (the semantic) in

execution environments makes the services. The

design of the node allows selecting what packet

must go towards a specific service.

One of the initial objectives of the active networks

research group (Tennenhouse,1996) has been to

design networks with capacity of fine re-

programming so that they can allow new protocols

in a transparent way. Therefore, a good design of an

active node does not have to circumscribe to a

specific protocol. In fact, it will allow the node to

manage new protocols.

Until now the proposed solutions have a basic

problem: how to segment the incoming traffic and to

distribute it towards its active services. It is

necessary a criterion in each individual packet to

allow selecting a specific target execution

environment. A first approach to solve this question

could be to use the origin and target address as a

selection criteria, with the main disadvantage of not

allowing to distinct more than a flow for each pair

(sender, receptor). Other way to solve this question,

which is the most used solution, is to use the field

"port" of the transport protocols to distribute the

traffic, nevertheless these causes that this traffic has

necessary a TCP or UDP layer (in the case of IP

networks) and therefore it is committed to use these

protocols., besides loosing the necessary flexibility.

Our approach is oriented to guarantee flexibility,

creating a design of active nodes that does not fit its

traffic to a particular protocol and thus allowing

using anyone, even without knowing it a priori, but

preserving the capacity to segment the traffic in a

powerful and individual way.

VAIN architecture has been thought to be used over

IP protocol, nevertheless this is not a limitation,

since it is possible to extend its operation to other

existing protocols or designs. VAIN does not force

at any moment to use a specific network protocol,

although it recognizes the traditional ones by means

of his declaration in the "network scheme". This

scheme can be completed in-band or out-band with

new designs without the need of re-programming the

node entirely or affecting other flows of information.

The following sections will show the VAIN

architecture describing its fundamental components:

The description of the model as three layer

architecture, the internal architecture of the node, its

implantation and the deployment stages for using it.

2 VAIN - VIRTUAL ACTIVE IP

NODE

As we have already said, VAIN has been designed

for marketplaces and collaborative commerce. This

goal is reached through an abstraction layer that

enables complex designs that look for the

collaboration between final entities. These entities

only need to agree in the operations of their business

since the architecture hides the peculiarities of the

network. At the same time this abstraction allows

independence between the virtual design and the

infrastructures of the communication supplier.

VIRTUAL ACTIVE IP NODE FOR COLLABORATIVE ENVIRONMENTS

2.1 Three layers virtual active

networks

Our solution is addressed to support collaborative

commerce on Internet and is based on

conceptualizing the active nodes as devices of three

layers: (1) Communications layer: where the

communication between active nodes and other

devices assures the network connectivity. (2)

Execution layer: its goal is to control the execution

of the Execution Environments (EE) and to

guarantee the right security and concurrence rules.

(3) Virtual layer: This one is the result of the

semantic of the guest code (the result of its

execution in an active node).

The sum of the layers of each one of the network

elements in an active network makes planes [figure

1]: (1) The communication plane includes the

traditional network on which is based the

infrastructure of active network. It has an own

addressing. The responsibility of this structure falls

into the transmission of packets between units of

commutation throughout all the plane (or sub plane).

(2) The execution plane is where the active nodes

give the required functionalities to equip the network

with the programming features. (3) And the virtual

plane establishes the lines, hosts, nodes and other

entities of the communication. It is projected over

the lower plane so that a given design is independent

of the lower ones (communications and execution).

As its name indicates, its semantic will change

depending on the services that implant it. This plane

organizes the partial semantics of the solution, that

is, the partial interaction of its elements in a tree

way, having as root the host leader and as terminals

the virtual active nodes called "meeting points".

The virtual active nodes correspond with EE of

physical nodes so that, although the design implies

more of a virtual node, it is executed in the same

physical node if the circumstances and restrictions

allow it. The communication lines establish the

directions and the starting and final points of the

flows of data between hosts and virtual nodes. They

do not correspond, necessary, with traditional

communication lines between network devices,

since they can be communications into the node.

Hosts can be source or target of these

communication lines and can be specialized.

2.2 Notation of a virtual plane

The different elements from the virtual plane are

integrated in the following notation [figure 2]: the

entities can have associated labels of diverse nature,

final hosts can take their name and direction; the

active nodes virtual labels do mention not only to its

address, but also to the requirements that must fulfil

(owner, features, modules, etc); meeting points

Initial or final entit

of the communication (leader hosts).

Pure virtual active node (VAN): point of execution of

uest code.

Meetin

point (MP) executin

uest code.

Meetin

area (MA): administrative zone of meetin

Area name

Virtual line of communications between elements (no safe line)

Virtual line of communications between elements (safe line, IPSec)

Line of communications with more than an element as ori

Line of communications with external elements to the virtual plane

Figure 2: Elements of the virtual plane

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(MP), like nodes of special purpose, inherit labels of

the pure virtual active nodes (VAN); meeting areas

(MA) have their administrative address and/or its

name; finally, the lines of communications can be

labeled with the name of the protocol – or protocols

– that they will support, in addition to the

restrictions in the ends, relative to the number of

maximum connections allowed. The [figure 2]

details the graphical elements associated with the

conceptual elements.

Two last graph lock up the semantics related

respectively to communications between an

indeterminate number of entities and

communications with entities outside the virtual

plane. First one adds to the design the notation to

show than an indeterminate number of elements (the

black point) will communicate with the related

entity. This graph will have, at the end of the well-

known organization, a label that indicates the

maximum number of simultaneous connections, as

well as the used protocol. An end of this line will

connect with a node whereas the other with a server

or service. A typical graph will represent a VAN

requesting guest code or necessary data for its

execution to an external server. Both graphs can be

represented by double lines to indicate a safe

communication.

3 THE VIRTUAL ACTIVE IP

NODE (VAIN) ARCHITECTURE

The technology that we have developed for the

construction of VAIN architecture is based on a

distribution process sufficiently rich and complex to

allow segmenting the incoming traffic using any

criterion, but conserving the flexibility of not fitting

the solution to a protocol or set of certain protocols.

The exposition has been "to make the distribution of

the incoming traffic using an expression that uses all

the possible semantics at the moment in which a

packet enters into the node". Our solution has been

to have as the criterion of segmentation of traffic to

flow, not only a concrete field of the head of packet

with a known protocol, but also a complex

expression that relates any value of this packet

without needing to know anything about the used

protocol.

As objective, this expression must recognize the

ownership of a certain packet and deliver a concrete

data flow to its corresponding service.

3.1 Stages of the distribution

There are two stages in the distribution: The creation

of the packet dictionary and the selection of the

target service.

The creation of the packet map, which is the

application of a network scheme that allows

recognizing the atomic units of information that the

packet contains, is carried out when the packet

enters in the node. The packet dictionary is created

at the same time that the map is outlined and intends

to define a set of pairs (field, value) that agglutinates

all the semantics recognized by the scheme of

network for that specific packet.

Finally, the selection process uses the dictionary

generated in the previous stage to evaluate the

network expressions and therefore to discover the

target services of the packet.

I/O Modules have two goals (1) To isolate node

engine from the special features of the data capture

and of the injection on the wire; (2) To allow

isolating the different net address formats. Although

VAIN have been created to run over IP, it is so easy

extending it to IPX, ATM or any other format that

fulfil requirements of an OSI net layer (or even link

layer).

3.2 The network scheme

The network expressions combine operands and

operators (logical, arithmetic, relational and bit

level) forming a complex expression. The operators

can be constant or references, the latter are solved by

using the packet dictionary created in the first stage

of the distribution.

Basically the network scheme indicates all structural

possibilities of a packet. Its declaration is made in

the node dictionary (its repository of information) in

XML format, and in memory, like a directed graph

(and at the same time like a list doubly connected).

The scheme can be public (one per node) or private

(one or more per service). The services can

incorporate entries (in runtime and in XML format)

so that the process recognizes private network

schemes. The packet dictionary is the result of the

creation its map. It is used as repository of

information in the resolution of the network

expressions, where references to the fields are

solved as they are needed.

VIRTUAL ACTIVE IP NODE FOR COLLABORATIVE ENVIRONMENTS

4 IMPLANTATION AND

CURRENT STATE

In this document we have shown an architecture

which allows us to increase the semantic of a

communication, stating that logic can be shared

between participants without the need of a central

point that coordinates them. Mainly, VAIN allow

each participant to design their own virtual active

network and extend it along Internet allowing

“points of presence” (services) which interact with

others one from others users.

Expressions based delivery is a powerful and

flexible tool to deliver input traffic into services,

allowing these to be able to be used smartly,

adapting itself to any situation, present and future.

The advantage of this strategy with respect to others

is clear: the independence of the native code of the

node regarding the traffic that crosses it. In addition

it allows the implantation of a node without knowing

the protocols that will handle those of network level

and link beforehand.

However the proposed solution presents a clear

drawback: efficiency. Inside the implantation of the

node finding and measuring bottle necks are

fundamental. In our architecture we have basically

two: the distribution of packets and the processing of

these in the services.

The design of the virtual plane that we have

proposed tries to link under a single implantation the

solutions to the collaboration challenges and

marketplaces, reached under different technological

solutions until now. The virtual plane joins the

partial semantics of the solution; our challenge from

now on is to add its complete, enriching the notation

and implanting gateway services to other

technological solutions. In addition to this the

transparency of the implantation must be maintained

in order to avoid reaching a point of critical mass,

which will cause the architecture to be a

construction sufficiently ineffective so that it avoids

its growth.

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K. L. Calvert, ed. “Architectural Framework for Active

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