The features of messaging are reliability for information broadcasting of information asrincrunes and srincrunes communication between the systems location independence protocol transperancy and decoupling between the systems

1. Reliability means garneted information delivery

2. Broadcasting means sending same information to multiple systems

3. Asynchronies communication means offline message delivery

a. In this case systems need not to be active 24*7

4. Location independence means systems need not be aware of network locations the messaging will hide network information from the applications

5. Protocol transparency means applications doesn't need to follow different protocols they all need to follow one common messaging protocol.

6. Di-couple means systems will not be communicating directly with each other

a. The advantage is if a system changes that will not effect other systems

7. The messaging software dose not perform data transformation and validation its only responsibility is transferring the data. The messaging concept is derived from radio broadcasting. The web service concept is derived from messaging.

8. The disadvantages are messaging services are not reusable and they are vender specific

RV ---- Rendezvous

RV provides 3 types of communication models

a. Asynchronies

b. Synchronies

c. Broadcast request reply

RV provides 2 types of messing models

1. Broadcast (Publish and subscribe)

2. Unicast or point to point

RV follows subject based addressing

A subject is logical address for information

A subject is similar to frequency in radio broadcasting

To get information applications should specify only subject

They dont need to be aware of network information about the systems

RV is based on UDP protocol

UDP stands for User Datagram Protocol

The advantages of UDP protocol are faster information delivery and server less or connection less

The disadvantages are no reliability for information and less security

In order to provide reliability RV has implemented a protocol called TRDP which is based on UDP protocol

TRDP stands for Tibco reliable data protocol

The features of TRTP are message sequencing message buffering and message retransmission

Even tho RV is based on unreliable protocol with the help of TRDP RV provides reliability for information

RV applications can use TRDP or PGM

PGM stands for pragmatic general messaging

While installing RV software either TRDP or PGM should be selected

RV follows bus architecture

In bus architecture there will not be any central component

Bus architecture is similar to peer to peer network

Complete RV set up should exists on each of the RV system un like client server model

In RV the message exchange is done with the help of RVD

RVD stands for RV Daemon

On each of the RV system RVD should be running

RVD is a background process when ever applications starts exchanging messages then only it comes to foreground

In order to connect to RVD application should create RV transport object

The parameters for RV transport object are

3. Network =""

4. Service=7500

5. Daemon=tcp:7500

Daemon specifies listening port number for RVD

Service specifies UDP implementation through which RV messages will be published or subscribed

Network specifies the current network interface

If the system has multiple network interfaces the network information should be specified explicitly

Remote Daemon connectivity is also possible which means connecting to the RVD which is running on different system. If this modal is used then it will be HUB and SPOKE model

Applications connect to RV using TCP protocol but RVD's communicate using UDP protocol

Generally TCP is point to point protocol where as UDP is broadcasting protocol

When ever publisher broadcast message that message will be sent to all the subscribing RVD nodes irrespective of subscribers interest for that message

When ever subscribing RVD receives message it till compare incoming message subject with the subscribers subject

If they are matching then only the subscribing RVD delivers message to the Subscriber

If the subject names are not matching the message will be discarded.

This is different from JMS broadcasting.

The syntax for subject name is

..

The scope indicates publisher

The object indicates information about message

The filter indicates subscriber type

The length of subject name should be less than or equals to 255 characters including dot(".") as a separator. Subject name is case sensitive.

Subject name should not start with _(Underscore )

Because these subjects are used for exchanging RV administrative messaging

Subject name should not start with numbers

The subject name will be determined by publisher. Which ever subscriber is interested in receiving information from that publisher and for that type of information they should specify same subject name

Two wild card characters are available for subject names

They are * and >

"*"Indicates one element

">" Indicates one or more elements

Wild chard characters should be specified only at subscriber side

Using wild card char a subscriber can receive messages from multiple subjects with in the same process

Generally one process will be required for one subject

RV provides 4 types of quality of services

6. Is RVR -- RV Reliable

i. RVR provides faster information delivery with only time based reliability

7. RVCM -- RV certified messaging

i. RVCM provides 100% reliability for information

8. RVTX -- RV transaction (deprecated)

i. RVTX provides transactional message delivery

9. RVDQ -- RV distributed messaging

i. RVDQ provides load balanced message delivery