Hammond Street Developments Pty Ltd

Case Study: Lawful Interception

HSD expertise fills essential need for Australian Internet Service Providers

HSD has been active in the LI (Lawful Interception) industry for more than a decade, during which time it has provided LI solutions for a variety of small and medium-sized Australian ISPs.  A standard feature of these solutions has been the use of HSD's Generic Traffic Interception System (GTIS) to implement lawful interception based on a legal warrant.


The Telecommunications Act 1997 and subsequent amendments defines Internet Services Providers' (ISP) obligations under Australian law with respect to telecommunications interception.  In short, ISPs are obliged to maintain an interception capability and facilitate the lawful interception of subscriber content when served with a legal warrant targeting a subscriber's services.

Business Needs

The main needs of ISPs in this situation are:

  1. Regulatory Compliance – ISPs must meet their regulatory lawful interception obligations, failure of which represents a significant business risk.
  2. Warrant Management – the management of a legal warrant targeting a specific subscriber's services must be central to any lawful interception solution.
  3. Ease of Use – the warrant management system must be easy to use by non-technical staff.
  4. Standards Compliance – the lawful interception solution must support the formatting, packaging and delivery of content according to the relevant Australian standards.


Central to HSD's LI solution is the Generic Traffic Interception System (GTIS).  GTIS is a turnkey hardware/software solution that has been in active development for the past decade, and is currently at release 4.  GTIS satisfies the business needs of ISPs and eases the burden of regulatory compliance.

An important aspect to the success of the GTIS solution has been the complementary consulting services provided by HSD to support the initial deployment and ongoing support of the system.  In this capacity, HSD leveraged its extensive network engineering experience and product knowledge to integrate the system into ISPs' networks and help troubleshoot any issues.  In some cases, this extended to developing custom software to integrate GTIS into an ISP's existing LI infrastructure.

GTIS comprises a number of modular components ranging from the network layer through to the application layer, as follows:

  • Probe – the network probe component that supports the capture of traffic at line speed using hardware-based packet capture.  Software-based capture is also supported for configurations where performance, i.e. bandwidth, requirements are less demanding.
  • Mediation – the central component of the system that co-ordinates the lawful interception of subscriber services.  Mediation incorporates an easy to use, web-based, warrant management application (WMA) that supports data entry of a warrant and related entities.  Mediation also includes modules that support the formatting, packaging and delivery of content according to the relevant Australia standards.
  • Trigger – the component of the system that supports so called "triggered" intercepts, that is, an intercept triggered on receipt of an external network event such as a subscriber logging into their service.  Trigger supports the following protocols/services:
    • L2TP – Layer 2 Tunneling Protocol
    • RADIUS – Remote Authentication Dial In User Service
    • VoIP - SIP-mediated Voice-over-IP telephony services


GTIS has been in operational use in small to medium-sized ISPs for a number of years.  The main benefits that have been realised over this period include:

  • Regulatory Compliance – ISPs have met their regulatory LI obligations thereby minimising business risk.
  • Simplified Warrant Administration – the WMA application simplifies the administration of warrants by non-technical staff.
  • Legal Certainty – the strict application of the parameters of a warrant, e.g. start/stop time, ensures that the content that is captured is strictly within the constraints of a warrant.
  • Operational Stability – GTIS has proven itself to be a robust and mature product that has consistently and reliably delivered content to law enforcement agencies within the legal constraints of a warrant.
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Solution Overview

Organisation Profile

Small and medium-sized Australian ISPs


Government, Telecommunications

HSD Services

  • Java Development
  • Systems Management & Support

HSD Solutions

  • Lawful Interception

Business Need

  • Regulatory compliance
  • Warrant Management
  • Ease of Use
  • Standards Compliance


  • Custom developed proprietary turnkey hardware and software solution
  • Complementary consulting services


  • Regulatory Compliance
  • Simplified Warrant Administration
  • Legal Certainty
  • Operational Stability


  • Endace DAG (Data Acquisition and Generation) cards – enables hardware-based capture in the network probe component
  • Java/C programming language
  • JBoss (Java) Application Server
  • Hibernate ORM (Object Relational Mapping) library
  • Spring Framework (open source application framework and Inversion of Control container for the Java platform)
  • PostgreSQL RDBMS
  • Linux O/S (UNIX shell and standard utilities)
  • RHEL (Red Hat Enterprise Linux) Kickstart – enables the automated installation of a custom GTIS distribution running on RHEL (currently version 6)