IRLP and EchoLink Integration

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IRLP and EchoLink Integration

• Tony Langdon VK3JED
• For the IRLP Conference
• Las Vegas, USA
• April 16-17 2005

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Contents

• IRLP and EchoLink Differences.
• Guidelines for Interoperation.
• Early Dual System Nodes.
• EchoIRLP 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.

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IRLP and EchoLink - Differences

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

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Guidelines for Interoperation

• Cultural differences need to be taken into
  account when combining different networks.
• IRLP-EchoLink guidelelines documented in late
  2002.
• Acceptable scenarios for combining IRLP and
  EchoLink.
• Dual system node - EchoIRLP.
• Linked IRLP/Echolink conferences.
• Common conference server.
• Emergency Communications VoIP WX Net.

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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.

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EchoIRLP - The Integrated Dual Node

• Uses one machine and interface to allow
  connectivity to both systems.
• Lockouts between IRLP and EchoLink to prevent
  unintentional cross links.
• Uses tbd as a local gateway between IRLP
  controlling the hardware and the EchoLink network.

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EchoIRLP Block Diagram
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Linking Nets Analog Gateways

• Consist of IRLP and Echolink nodes back to back.

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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.

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Digital Interconnections

• EchoLink conference capable of making an outbound
  Speak Freely connection.

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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 EchoLink.
• IRLP stations must use GSM CODEC for digital link
  to work.
• Traffic passes directly between IRLP and EchoLink.

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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 EchoLink station list.
  IRLP nodes are labelled stnXXXX.
• Conference to be administered using both EchoLink
  and IRLP admin tools.
• Allows IRLP nodes to be muted not normally
  supported.

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Practical Uses of Cross Links

• Emergencies VoIP Hurricane/SKYWARN Net.
• Regional coverage New England Network.
• Special Events 2003 9/11 Net.

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Looking to the Future

• Digital interconnection for eQSO?
• Dialogue opened with current maintainer of eQSOx.
• Establishment of an inter-system linking
  standard?
• 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!

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Acknowledgements

• Dave Cameron VE7LTD IRLP System
• Jonothan Taylor K1RFD EchoLink
• Skip Hansen WB6YMH thebridge
• Pete Illmayer VK2YX EchoIRLP update server
• Kent Johnson W7AOR Test reflector
• EchoIRLP Developers Open source has many
  contributors.
• And all those hams who offered positive feedback
  and made it all worthwhile.