Delivering Serverless IP Telephony to the Enterprise Simon Bryden VP Engineering, Popular Telephony.

Delivering Serverless IP Telephonyto the Enterprise

Simon BrydenVP Engineering, Popular Telephony

What's wrong with servers?

• They're expensiveo High start-up costo Typically high maintenance/support overhead

• Initial learning curveo Blocking factor for small businesses

• Single point of failureo loss of server impacts all clients

A Tempting Proposition...

User Manual

Step 1: Unpack phones

Step 2: Plug them in

Step 3: Start calling

Serverless Architecture

Serverless Challenges

• How to route calls?• Call state tracking• Storage

o address bookso voicemailso call registers

• Feature implementation• System administration

Data Storage

• Storage on local terminalso ties terminals to peopleo use broadcast-based retrieval

• Distributed storageo access from any terminalo resilient to loss of terminalso DHT-based storage/retrieval

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

Distributed Hash Tables

• At startup, new peer needs to find existing peers

• Several mechanismso IP multicasto Registration pointo Preconfigured rangeso Cached lists

Data Storage - detailskey=”login:100”

data=”sip:[email protected]”

key hash=>node 7

Node 1

Node 7

Node 8

Node 9

Node 6

Node 5

Node 4

Node 3

Node 2

Data Storage – conceptual view

key=”login:100”data=”sip:[email protected]

Distributed Intelligence

• Terminals must understand features• Call control more complex

o compared to standard IP phone

Example Call Flow

Login as “100”

login:100sip:[email protected]

Example Call Flow



Login as “101”

Example Call Flow



Request “login:101”

Dial “101”

sip:[email protected]

100

101

Example Call Flow



100

101

Feature Example: Pickup



ring:sales101

101

100




ring:sales100:101

Request “ring:sales”

Pickup

100

101

103

“100:101”




ring:sales100:101

Redirect to 103


Deletering:sales

100

103

101





101

100

103



login:101sip:[email protected] login:103


100

101

103

Feature Example: Park




park:385100

Park ID = 385

Park

100

101

103





park:385100

Call Parked

100

101

103





park:385100

Call Parked

Request “park:385”

Unpark 385

100

101

103

100





park:385100

Call Parked

Reconnect with 103Delete “park:385”

100

101

103





100

101

103

Roadblocks

• DHT implementation very complexo Need 100% guarantee of data locationo Need strong reliabilityo Limited storage on nodeso Limited performance nodes

• New features = new softwareo Need a good auto-update feature

Summary

• P2P telephony is the future• High-interest topic

o Vendors already shipping productso IETF involvemento Some open source interest

• Natural evolution

Thank You

Delivering Serverless IP Telephony to the Enterprise Simon Bryden VP Engineering, Popular Telephony.

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