how green is ip telephony
Download
Skip this Video
Download Presentation
How Green is IP-Telephony?

Loading in 2 Seconds...

play fullscreen
1 / 27

How Green is IP-Telephony? - PowerPoint PPT Presentation


  • 111 Views
  • Uploaded on

How Green is IP-Telephony?. Salman Abdul Baset*, Joshua Reich * , Jan Janak**, Pavel Kasparek**, Vishal Misra*, Dan Rubenstein*, Henning Schulzrinne* Department of Computer Science, Columbia University* Tekelec Corporation**. Traditional Telephony. Place call ( Signaling ) Directory lookup

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'How Green is IP-Telephony?' - yuri


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
how green is ip telephony

How Green is IP-Telephony?

Salman Abdul Baset*, Joshua Reich*, Jan Janak**, Pavel Kasparek**, Vishal Misra*, Dan Rubenstein*, Henning Schulzrinne*

Department of Computer Science, Columbia University*

Tekelec Corporation**

traditional telephony
Traditional Telephony
  • Place call (Signaling)
    • Directory lookup
    • Circuit reservation
  • Talk (Connectivity)
      • Transfer voice data (analog, digital)
  • Variations on these themes
    • Multi-party conferencing
    • Voicemail
ip based communication systems
IP-Based Communication Systems

Telephony

And More

  • Place call (Signaling)
    • Directory lookup
    • Packet switched routes
  • Talk (Connectivity)
      • Direct packet routing
      • Media relaying
      • PSTN/mobile gateways
  • Video
  • IM
  • Status / buddy list
trends implications
Trends & Implications
  • Trend away from traditional telephony infrastructure
    • Vonage, Packet8, Verizon FiOS
    • Skype
    • Mobile
  • To single infrastructure (IP) for all data/voice/etc.
    • More efficient (one system to maintain, improve)
    • Much less expensive (for now)
    • More fragile (one system to fail)
    • More complex

So what does this mean energy wise?

our questions
Our Questions
  • Where is energy consumed?
  • How do different design choices effect energy consumption?
  • How we can make IP-telephony more energy efficient?
outline
Outline
  • IP-Telephony and power consumption
  • Answering our questions:
    • Where is energy consumed?
    • How do different design choices effect energy consumption?
    • How we can make IP-telephony more energy efficient?
  • Conclusion & Future Work
outline1
Outline
  • IP-Telephony and power consumption
  • Answering our questions:
    • Where is energy consumed?
    • How do different design choices effect energy consumption?
    • How we can make IP-telephony more energy efficient?
  • Conclusion & Future Work
ip communication flavors
IP Communication Flavors

Client-Server (C/S)

Peer-to-Peer (P2P)

ip communication flavors1
IP Communication Flavors

Communication

Addendum

Traditional Telephony

Replacement

how does c s ip telephony work
How Does C/S IP-Telephony Work?

SIP registrar /

proxy / presence

server

SIP registrar /

proxy server

IP-PSTN

gateway

REGISTER

(ip addr)

REGISTER

(ip addr)

(1) signaling

(1) signaling

(2) media

(voice, video, IM)

User agent

User agent

Utopian Internet

No NATs or firewalls

and in the real world
And In The Real-World…

SIP registrar /

proxy / presence /

server

media server

NAT / firewall

NAT / firewall

User agent

User agent

media servers bypass firewalls
Media Servers Bypass Firewalls

SIP registrar /

proxy / presence /

server

media server

IP-PSTN

gateway

(1) signaling

NAT / firewall

NAT / firewall

(1) signaling

(2) media

(voice, video, IM)

(UDP or TCP)

User agents

User agents

how does p2p ip telephony work
How Does P2P IP-Telephony Work?

media relay (or relay)

node A

node E

NAT / firewall

network address

of node B?

(3) media (TCP)

(2) signaling

(2)

(4) media

(1)

(3) signaling

P2P / PSTN

gateway

(1)

(1)

NAT / firewall

network address

of node E?

(2)

(1)

node B

(2) signaling

  • nodes form an overlay
  • share responsibilities for message routing, signaling, media relaying
  • super nodes, ordinary nodes

node C

node D

node = user agent

sources of energy consumption
Sources of Energy Consumption
  • End-point
    • Handsets
    • VoIP conversion boxes
    • PCs
  • Core
    • Signaling / directory
    • Media relaying
    • PSTN / mobile gateways
  • Network
assessing energy consumption
Assessing Energy Consumption
  • Power Meters
    • Wattsup
    • Killawatt
  • Hardware Measurements
    • SIP Server
    • Relay Server
    • Desktop clients
    • Laptop clients
    • Hardware SIP phones
    • Software phones
    • Skype peers
  • Data (from C/S VoIP provider)
    • 100 K users (mostly business)
    • 15 calls per second (CPS)
    • ~5K calls in system
    • NAT keep-alive traffic
    • All calls relayed
  • Modeling
    • C/S
    • P2P
outline2
Outline
  • IP-Telephony and power consumption
  • Answering our questions:
    • Where is energy consumed?
    • How do different design choices effect energy consumption?
    • How we can make IP-telephony more energy efficient?
  • Conclusion & Future Work
where is energy consumed
Where is Energy Consumed?

PSTN replacement

  • VoIP servers consume less than 0.04% of total!
    • >10K users, voice traffic
    • a server can handle signaling workload for 500k users
    • a server can handle media workload for 50k users
    • even after a redundancy factor of 2, and conservative PUE of 2!

Make PSTN replacement green? Reduce end-device power consumption.

where is energy consumed1
Where is Energy Consumed?

Non-PSTN replacement

  • More complicated
  • If softphone draws little additional power
    • Still likely that end-point biggest component
    • But may not dominate consumption
  • If users leave PCs on just as phones
    • Possibly even worse than PSTN!

.

User / hardware study needed.

how do design choices effect power consumption
media relay (or relay)

NAT / firewall

node A

node E

(3) media (TCP)

(2) signaling

SIP registrar /

proxy / presence /

server

media server

(1)

(1)

network address

of node E?

INVITE

NAT / firewall

node B

(2) signaling

NAT / firewall

INVITE

media

(voice, video, IM)

(UDP or TCP)

node C

node D

User agents

User agents

How Do Design Choices Effect Power Consumption?
  • C/S Inefficiencies
    • Power utilization efficiency – (PUE)
      • Ratio of data center power draw to IT power draw
      • e.g., cooling, network equipment, etc.
    • Idle power consumption (can be addressed in larger systems by techniques such as Somniloquy or Sleep Proxy
    • Percentage of user population that requires relaying major determinant of core energy consumption.
how do design choices effect power consumption1
media relay (or relay)

NAT / firewall

node A

node E

(3) media (TCP)

(2) signaling

SIP registrar /

proxy / presence /

server

media server

(1)

(1)

network address

of node E?

INVITE

NAT / firewall

node B

(2) signaling

NAT / firewall

INVITE

media

(voice, video, IM)

(UDP or TCP)

node C

node D

User agents

User agents

How Do Design Choices Effect Power Consumption?
  • P2P Consumption
    • Avoids these overheads by using machines that are already on
      • In theory general user population
      • In practice appears to be heavily subsidized by university machines
      • What happens when machines are idling less…
    • Incurs small additional energy use for signaling and relaying
      • But how small?
comparing c s and p2p
Comparing C/S and P2P
  • Compare under same load
    • Active calls
    • Call duration
    • Percentage of PSTN calls
  • Generic C/S and P2P
    • Both use standard VoIP (e.g., not Skype)
  • Isolate only services that differ between P2P, CS
    • Directory service
    • Call signaling
    • Media session
    • Presence
modeling p2p and c s
Modeling P2P and C/S
  • C/S model
    • C/S power consumption = #servers * Watts/server *redundancy factor * PUE
  • P2P model
    • S super nodes active
    • pssuper node consumption

P2P energy efficient when:

S *ps < C/S power consumption

  • One active super node per relayed call.
  • Media server fully loaded.
  • 100% calls relayed

ps = 52mW

P2P may consume more than C/S!

caveats
Caveats
  • Peers
    • External meters do not provide sufficient resolution to determine ps w/ confidence
    • Will be in different states when relay starts
      • Medium load unlikely to incur much extra overhead
      • Low or high loads, ps could conceivably be large
      • Consequently, prior distribution effects efficiency
  • Servers
    • Energy usage not linear w/ load
    • Lower utilization hurts energy efficiency
making ip telephony greener
Making IP-Telephony Greener
  • Make phones energy efficient
    • LCD, processor, WOL for phones?
  • NATs & Firewalls
    • Get rid of NATs or rearchitect them
    • Use TCP to avoid NAT keep-alive
    • Make firewalls VoIP-friendly.
  • Set up SIP user agents on gateways
  • PC wakeup on receiving calls
outline3
Outline
  • IP-Telephony and power consumption
  • Answering our questions:
    • Where is energy consumed?
    • How do different design choices effect energy consumption?
    • How we can make IP-telephony more energy efficient?
  • Conclusion & Future Work
conclusions
Conclusions
  • VoIP endpoints dominate total energy consumption in PSTN replacement systems
  • P2P not necessarily more energy efficient than C/S.
  • NATs and firewalls create the need for media relaying, one of the biggest components of core energy consumption.
future work
Future Work
  • Obtain data on PSTN power consumption
  • Work on accurately measuring ps
  • Measure path length / routing differences between of direct and media-relayed calls.
  • Study user behavior viz-a-vis softphone use
    • How much extra time are machines left on
    • Power draw during those periods
  • Develop WOL capable hard-phones
ad