• Specialised in signaling for nearly a decade, with the main emphasis on the protocol used in 99% of networks - signalling system #7 (SS7)
  • Was a SS7/C7 software engineer covering virtually every SS7/C7 layer/applications - MAP, TCAP, SCCP, INAP, ISUP, MTP, IS-41, BSSAP and standards ETSI, ANSI, Bellcore and ITU. For example he wrote the software decode for the Chinese INAP. He worked as a software engineer for both the acceSS7 and HP3900 platforms.
  • Was a protocol software engineer responsible for a proprietary telecommunications protocol system involving communications between transactions terminals out in the field and a central UNIX host.
  • Played a leading role in achieving national SS7/C7 certifications for a switch and a softswitch produced by a major Internet equipment manufacturer.
  • Performed switch installations as well as post installation SS7 testing.
  • Performed SS7/C7 testing for many variants including Swedish ISUP, UK ISUP, NUP/IUP and Russian ISUP in addition to the more common ITU and ANSI protocols.
  • Performed testing against one of the world's most complex Intelligent Network (IN) platforms, certifying the SCCP and TCAP SS7/C7 protocols.
  • Has unique knowledge of SS7/C7 Security aspects and provides consulting on signalling security issues largely to parties involved in VoIP and 3G implementations.
  • He is lead-author of the most comprehensive book on SS7/C7 - "SS7/C7 Protocol, Architecture and Services" (Cisco Press) and is regularly invited to be a speaker at international seminars.
• Since the initial 3G rollouts in 2001 has provided hands on 2/2.5 and 3G support and later service additions as well as 3GPP lead architecture changes. Such support has included SS7, SIP, H.323, CODECs/transcoding and softswitch management.
• Has been working in Next-Generation Network (NGN) environments since first rollouts in 2004.
  • Wrote and performed SS7 to SIP interworking tests.
  • Dealt with signalling issues such as SIP/H.323/SS7 interworking for PSTN calls.
  • Tested 3G services such as video calling and location based services which require such signalling interworking.
  • Managed softswitches and media gateways since 2004.
  • Played a leading role in BICC/ISUP/SIP interworking verification for a softswitch produced by a major telecoms equipment vendor.
• Has spent 8+ years delivering signalling related training on an international basis. He currently provides training in signaling system #7 (SS7/C7 including application level protocols: INAP, CAMEL, GSM-MAP, ANSI-41 MAP), SS7oIP (namely SIGTRAN: M3UA, M2UA, SUA, M2PA), IP centric signalling (namely H.323, SIP, P2P SIP, Jingle) as well as the some of the technologies behind Web 2.0 (e.g. RSS, ATOM, Microformats), Web 3.0 (primarily Semantic Web: RDF, RDFS, OWL) and the intersection of voice enabled communications with the Web 2.0/Web 3.0 technologies.
• He is a member of The Institution of British Telecommunications Engineers (IBTE), The Professional Contractors Group (PCG), The Federation of Telecommunications Engineers of the European Community (FITCE), The British Computer Society (BCS), The Institution of Electrical Engineers (IEE) and The Institute of Electronic and Electrical Engineers (IEEE).

If you would like to purchase his SS7/C7 book, please click here. He can be contacted directly at or , Skype ID 'leedryburgh'.