IRLP and Echo Link Integration Tony Langdon VK

IRLP and Echo. Link Integration Tony Langdon VK 3 JED For the IRLP Conference Las Vegas, USA April 16 -17 2005

Contents ● ● ● IRLP and Echo. Link – Differences. Guidelines for Interoperation. Early Dual System Nodes. Echo. IRLP – The Integrated Dual Node. Linking Nets – The Analog Gateway. Problems With Analog Gateways. Digital Interconnections. Advantages and Constraints of Digital Links. The Integrated Conference. Practical Use of Cross Links. Looking to the Future. Questions.

IRLP and Echo. Link - Differences ● ● ● ● IRLP is an RF only system. Echo. Link permits direct PC access. IRLP uses PGP for authentication. IRLP nodes owners have to contact installation team to receive their PGP keys. Echo. Link uses validation against online databases, with some applicants being hand validated. Echo. Link uses encrypted password login. Technical differences have resulted in significant cultural differences.

Guidelines for Interoperation ● ● ● Cultural differences need to be taken into account when combining different networks. IRLP-Echo. Link guidelelines documented in late 2002. Acceptable scenarios for combining IRLP and Echo. Link. – – Dual system node - Echo. IRLP. Linked IRLP/Echolink conferences. Common conference server. Emergency Communications – Vo. IP WX Net.

Early Dual System Nodes ● ● ● Many consist of two separate PCs and radios feeding the one repeater. More sophisticated systems use 2 PCs and 1 radio. These systems are prone to unintentional cross links. Many allow DTMF access to foreign network as a byproduct of their design. Audio quality is compromised, especially in systems using separate link radios.

Echo. IRLP - The Integrated Dual Node ● ● ● Uses one machine and interface to allow connectivity to both systems. Lockouts between IRLP and Echo. Link to prevent unintentional cross links. Uses tbd as a local gateway between IRLP controlling the hardware and the Echo. Link network.

Echo. IRLP Block Diagram

Linking Nets – Analog Gateways ● Consist of IRLP and Echolink nodes back to back.

Problems With Analog Gateways ● ● Multiple audio compression/decompression degrades audio quality. Excess latency caused by jitter buffers. Requires two extra PCs – cost and reliability issues. However, analog gateways have one advantage – they can be implemented at short notice without administrative intervention.

Digital Interconnections ● Echo. Link conference capable of making an outbound Speak Freely connection.

Issues of Digital Links ● ● ● Audio is not decoded and recoded as it passes the gateway. Less audio degradation. Lower latency. Extremely difficult to tell whether originating station is on IRLP or Echo. Link. IRLP stations must use GSM CODEC for digital link to work. Traffic passes directly between IRLP and Echo. Link.

The Integrated Conference ● ● ● Modified IRLP reflector – Developed March-April 2005. Copy of sfreflect is replaced by tbd. One system – very reliable. All stations appear in Echo. Link station list. IRLP nodes are labelled “stn. XXXX”. Conference to be administered using both Echo. Link and IRLP admin tools. Allows IRLP nodes to be muted – not normally supported.

Practical Uses of Cross Links ● ● ● Emergencies – Vo. IP Hurricane/SKYWARN Net. Regional coverage – New England Network. Special Events – 2003 9/11 Net.

Looking to the Future ● Digital interconnection for e. QSO? – ● Establishment of an inter-system linking standard? – – ● ● ● Dialogue opened with current maintainer of e. QSOx. RTP based? Standard would give all developers, including commercial ones something concrete to implement. Global Inter-Network Addressing? Co-operation between stakeholders allows rapid development. Limited only by imagination!

Acknowledgements ● ● ● ● Dave Cameron VE 7 LTD – IRLP System Jonothan Taylor K 1 RFD – Echo. Link Skip Hansen WB 6 YMH – thebridge Pete Illmayer VK 2 YX – Echo. IRLP update server Kent Johnson W 7 AOR – Test reflector Echo. IRLP Developers – Open source has many contributors. And all those hams who offered positive feedback and made it all worthwhile.