QTP as Transaction Transport Layer

1
QTP as Transaction Transport Layer

• High-capacity, connection-oriented transaction
  transport
• Cameron_Young_at_inetco.com
• [phone]

2
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.

3
Typical POS Architecture
Network Access Controllers or FEP
POS Terminals (1000s to 100ks)
Institutions EFT TPs
X.25/Dial Access Network
SNA/X.25/FR Access Network
Message
Message (ISO8583 or other)
Visa, TPDU, CLNP, TPDU
Visa, TPDU, CLNP, None
X.25, FR, IP
HDLC, X.25, Async
4
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
• gt100k transaction terminals
• gt100 financial institutions
• Initial peak 500 TPS with scalable growth

5
IP-oriented Architecture
INAC clusters
Remote Access Servers
POS Terminals
Institution EFT TPs
IP Network
X.25/Dial Access Network
SNA/X.25/FR Access Network
Message (as is)
Message (as is)
Message (ISO8583 or other)
Transport (as is)
Host transport
Visa, TPDU, CLNP, None
QTP
X.25, SNA, FR
HDLC, X.25, Async
UDP/IP
6
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

7
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

8
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.