Delivering Serverless IP Telephony to the Enterprise

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Delivering Serverless IP Telephonyto the
Enterprise
Simon Bryden VP Engineering, Popular Telephony
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What's wrong with servers?

• They're expensive
• High start-up cost
• Typically high maintenance/support overhead
• Initial learning curve
• Blocking factor for small businesses
• Single point of failure
• loss of server impacts all clients

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A Tempting Proposition...

• User Manual
• Step 1 Unpack phones
• Step 2 Plug them in
• Step 3 Start calling

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Serverless Architecture
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Serverless Challenges

• How to route calls?
• Call state tracking
• Storage
• address books
• voicemails
• call registers
• Feature implementation
• System administration

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Data Storage

• Storage on local terminals
• ties terminals to people
• use broadcast-based retrieval
• Distributed storage
• access from any terminal
• resilient to loss of terminals
• DHT-based storage/retrieval

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Distributed Hash Tables

• Used to map a data object to one or more nodes
• Each node has small number of peers
• Peers forward requests to their peers
• Typically order log2(n) hops to retrieve data
• Extremely scalable

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Distributed Hash Tables

• At startup, new peer needs to find existing peers
• Several mechanisms
• IP multicast
• Registration point
• Preconfigured ranges
• Cached lists

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Data Storage - details
Node 9
Node 1
Node 8
Node 7
Node 2
Node 6
Node 3
Node 4
Node 5
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Data Storage conceptual view
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Distributed Intelligence

• Terminals must understand features
• Call control more complex
• compared to standard IP phone

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Example Call Flow
Login as 100
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Example Call Flow
Login as 101
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Example Call Flow
Dial 101
Request login101
100
sip101_at_192.168.0.35
101
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Example Call Flow
100
101
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Feature Example Pickup
100
101
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Feature Example Pickup
Pickup
103
Request ringsales
100101
100
101
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Feature Example Pickup
Redirect to 103
103
Deleteringsales
100
101
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Feature Example Pickup
103
100
101
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Feature Example Pickup
103
100
101
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Feature Example Park
Park
103
Park ID 385
100
101
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Feature Example Park
Call Parked
103
100
101
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Feature Example Park
Call Parked
103
100
Request park385
100
101
Unpark 385
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Feature Example Park
Call Parked
103
100
Reconnect with 103
Delete park385
101
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Feature Example Park
103
100
101
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Roadblocks

• DHT implementation very complex
• Need 100 guarantee of data location
• Need strong reliability
• Limited storage on nodes
• Limited performance nodes
• New features new software
• Need a good auto-update feature

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Summary

• P2P telephony is the future
• High-interest topic
• Vendors already shipping products
• IETF involvement
• Some open source interest
• Natural evolution

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• Thank You