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QTP as Transaction Transport Layer

High-capacity, connection-oriented transaction transport

Cameron_Young@inetco.com

(604) 451-1567

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Introduction

Who is INETCO? Software vendor linking institutions

with terminals See www.inetco.com

Our perspective Financial/retail vertical market Financial TP is often “Most mission

critical application” We make new elements evolving

into a system communicate with what is already there.

Normally we work in all layers below ISO8583 or equivalent message.

Why are we here? Joint authors of QTP - transport

protocol for POS transactions over IP.

SOAP/HTTP emphasizes client-web-server interaction. QTP addresses concentration points (back-end).

Scope Deal with communication issues,

not use of RPC vs. Message API.

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Typical POS Architecture

X.25/DialAccessNetwork

SNA/X.25/FRAccessNetwork

NetworkAccess

Controllersor FEP

POSTerminals

(1000s to 100ks)

InstitutionsEFT TPs

Visa, TPDU, CLNP, TPDUVisa, TPDU, CLNP, None

X.25, FR, IPHDLC, X.25, Async

MessageMessage (ISO8583 or other)

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Transport Layer Requirements

Performance Fast connection processing High availability

Security Restrict by source access network

address Restrict by source transport-layer

address Restrict RAS - INAC communication Provide legal intercept

Transaction delivery Either non-reliable delivery, or Reliable delivery with end-to-end

data acknowledgements

Access Network independence X.25, FR, Dialup, ...

Transport layer independence TCP or UDP, FR, other

Scaling >100k transaction terminals >100 financial institutions Initial peak ~500 TPS with scalable

growth

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IP-oriented Architecture

IPNetwork

X.25/DialAccessNetwork

SNA/X.25/FRAccessNetwork

RemoteAccessServers

INACclusters

QTP

POSTerminals

InstitutionEFT TPs

X.25, SNA, FRHDLC, X.25, Async

UDP/IP

Message (as is) Message (as is)Message (ISO8583 or other)

Transport (as is) Host transportVisa, TPDU, CLNP, None

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QTP Overview

Status Released as Internet Draft:

draft-cornish-qtp-01.txt First applications in production Incorporated by other vendors. Opensource version available for

draft-cornish-qtp-00.txt

Characteristics Lightweight connection multiplexing Symmetric Individual message acks Status for source routing decisions. Independent of lower-level transport Attribute/Value based Extensible

Header Version Msg ID, Msg ID Ack, Priority flags Length Src / Dest Logical Channel Number Optional Msg ID, Msg ID Ack values

Attributes for Session establishment Data transfer Session management Element status Statistical information Vendor extensions

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QTP Attributes

Session Establishment Called / Calling party addresses Called / Calling party subaddresses Address family (E.164, X.121, …) Profile, speed, idle timeout Max message Protocol identifier Customer group identifier

Data Transfer Data / Block data Management info Q Data / Call Data

Session Management Cause (Normal, various QTP causes) Remote cause (Normal, various Access

causes)

Element Status Flow control state (Available, Congested) Station status (Primary, Secondary, …) Ping Call state

Statistical Information Messages received / sent Unacked messages Time since last restart

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Closing Comments

QTP not a fit for client side, unless client is really a gateway / proxy for many transaction generators.

Primary incentive for choosing QTP today is scaling beyond TCP session limits. QTP addresses concentrated connection-oriented transactions.

May be future interest in SOAP over QTP. Would require split into SOAP encapsulation and SOAP over HTTP specs.

As transaction concentration increases, so does emphasis on security, reliability, and performance.