Your SlideShare is downloading. ×
VoIP (ppt)
Upcoming SlideShare
Loading in...5
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×

Saving this for later?

Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime - even offline.

Text the download link to your phone

Standard text messaging rates apply

VoIP (ppt)

5,224
views

Published on


1 Comment
4 Likes
Statistics
Notes
No Downloads
Views
Total Views
5,224
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
331
Comments
1
Likes
4
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
No notes for slide

Transcript

  • 1. Packet Voice Protocols and VoIP Fall 2002 – Computer Networking Seyed Ali Ahmadi
  • 2. VoIP Technology
    • Identify the different generations of VoIP
    • Explain the basic operations of a VoIP Gateway
    • Describe an ITSP business case
    • How gateway architecture affects service providers
  • 3. VoIP technology
    • Recent Evolution of packet voice and VoIP
    • VoIP technology
    • VoIP evolution scenarios
  • 4. 1- Recent Evolutions in VoIP
    • Describe existing voice over data architectures and name their predecessors
    • How an ITSP work ?
    • Characteristics of an Internet call
    • Advantages and Disadvantages of ITSP
  • 5.  
  • 6.  
  • 7.  
  • 8.  
  • 9. VoFR and VoATM Are Similar to VoIP
    • Voice is sent as packets intermingled with other traffic types
    • Voice may be compressed for efficiency
    • Delay and Delay variation are issues
    • Priority for voice traffic is required for best performance
  • 10.  
  • 11. VoIP Generations
    • PC-to-PC
    • PC-to-Phone
    • Phone-to-Phone
    • Traditional PBX migration to VoIP
    • IP PBX
  • 12. ISTP Technology
    • Different Types of IP calls
    • How ITSP deploy gateways
  • 13.  
  • 14.  
  • 15.  
  • 16.  
  • 17. Generic Gateway
  • 18.  
  • 19.  
  • 20. Dedicated Infrastructure for ITSP
    • Eliminate dependence on performance of the Internet
    • Carries strictly voice traffic or Prioritize voice over data
    • Offers cheap long distance as initial service
    • Positioned as enhanced service provider from regulatory point of view
  • 21.  
  • 22.
    • Place gateways in countries with high international tariffs or high calling volumes.
    • These Gateways support standard end user business interfaces to PSTN
      • T1
      • E1
      • Analog
      • ISDN
  • 23.  
  • 24.  
  • 25.  
  • 26. Regulatory Status
    • Most of the world has taken a hands-off position in regulating the enhanced service providers
    • In genera ITSPs have mostly positioned them as ISPs
    • As a result, ITSPs typically do not pay carrier fees such as connection, access or settlement fees
    • IP telephony is regulated in some countries and illegal in some others.
  • 27.  
  • 28. 2- VoIP Protocols and Technology
  • 29.
    • A little on history
    • Communication pattern shift from PSTN to VoIP
    • Why VoIP?
      • Cost saving
      • Open standards and Multivendor interoperability
      • Integrated voice and Data network
  • 30. VoIP Protocols
    • H.323
    • Media Gateway Control Protocol (MGCP)
    • Session Initiation Protocol (SIP)
    • H.248–Media Gateway Control (MEGACO)
  • 31. Great Voice Myth
    • “ In order to have a reliable and robust Voice network, there should be one and only one protocol for each function in packet switch network.”
    • This is not how we are actually doing it now!!
    • The VoIP networks of today and tomorrow will be constructed using the protocols and applications that best fit the associated technology and business requirements.
  • 32. Protocol Terminology
    • ITU: International Telecommunication Union
    • IETF: Internet Engineering Task Force
  • 33. Protocol Terminology
    • H.248 Gateway Control Protocol
      • Collaboration between ITU & IETF
      • Also referred to as IETF RFC 2885 (MEGACO)
  • 34. Protocol Terminology
    • H.323
      • ITU recommends for “ Packet based Multimedia communication systems”.
      • Most common VoIP protocol
      • Distributed Architecture
  • 35. Protocol Terminology
    • SIP: Session Initiation Protocol
      • IETF RFC 2543
      • Distributed Architecture
    • Real-time Transport Protocol – RTP
      • A transport protocol for real-time application
      • IETF RFC 1889
      • Provides transport for audio/media of VoIP communication
      • Used by All of VoIP signaling protocols
  • 36. Protocol Terminology
    • MGCP Media Gateway Control Protocol
      • IETF RFC 2075
      • Centralized Architecture for Multimedia applications such as VoIP
  • 37.  
  • 38.  
  • 39. Distributed vs. Centralized
  • 40. Centralized Architecture
    • Mostly used in older networks
    • Worked well for basic telephony services
    • Trade off between easy management and endpoint innovation
    • Associated with MGCP and H.248
    • Intelligence focused in centralized Gateway unit (media agent)
    • Endpoints are relatively or completely dumb.
  • 41. Centralized Architecture Pros & Cons
    • Centralizes management, provisioning and call control
    • Simplifies call flow for legacy voice features
    • Stifles innovation of endpoint features
    • Limitations in building VoIP networks beyond legacy voice features
  • 42. Distributed Architecture
    • Associated with H.323 and SIP protocol
    • Allows Network Intelligence to be distributed between endpoints and control devices.
    • Intelligence:
      • Call state
      • Calling features
      • Calling routines
      • … any aspect of call handling
  • 43. Distributed Architecture Pros & Cons
    • More flexible
    • VoIP is treated like any other distributed IP application
    • Well understood by engineers who design and run IP data networks
    • More complex than the Centralized Architecture
  • 44. H.323
    • Originally designed as a transport protocol for MM Apps. in LAN
    • Still used for Video Conferencing
    • Most widely used VoIP signaling and call control
    • Umbrella Protocol:
      • All aspects of call transmission
      • From call establishment to capabilities exchange to network resources
  • 45. H.323
    • Defines:
      • RAS
        • Registration
        • Admission
        • Status
      • H.225 for call set-up
      • H.245 for capabilities exchange