Transcript vkradio.com

IRLP and EchoLink Integration
Tony Langdon VK3JED
For the IRLP Conference
Las Vegas, USA
April 16-17 2005
Contents
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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.
IRLP and EchoLink - Differences
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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.
Guidelines for Interoperation
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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.
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Dual system node - EchoIRLP.
Linked IRLP/Echolink conferences.
Common conference server.
Emergency Communications – VoIP WX Net.
Early Dual System Nodes
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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.
EchoIRLP - The Integrated Dual Node
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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.
EchoIRLP Block Diagram
Linking Nets – Analog Gateways
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Consist of IRLP and Echolink nodes back to back.
Problems With Analog Gateways
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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
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EchoLink conference capable of making an
outbound Speak Freely connection.
Issues of Digital Links
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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.
The Integrated Conference
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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.
Practical Uses of Cross Links
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Emergencies – VoIP Hurricane/SKYWARN Net.
Regional coverage – New England Network.
Special Events – 2003 9/11 Net.
Looking to the Future
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Digital interconnection for eQSO?
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Establishment of an inter-system linking standard?
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Dialogue opened with current maintainer of eQSOx.
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
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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.