Presentation - HEAnet, Ireland's National Education ...
Upcoming SlideShare
Loading in...5
×
 

Presentation - HEAnet, Ireland's National Education ...

on

  • 851 views

 

Statistics

Views

Total Views
851
Slideshare-icon Views on SlideShare
849
Embed Views
2

Actions

Likes
0
Downloads
0
Comments
0

1 Embed 2

http://www.slideshare.net 2

Accessibility

Categories

Upload Details

Uploaded via as Microsoft PowerPoint

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

    Presentation - HEAnet, Ireland's National Education ... Presentation - HEAnet, Ireland's National Education ... Presentation Transcript

    • VoIP in Context
      • Niall O’Reilly, University College Dublin IT Services
      • HEAnet National Networking Conference 2006
    • VoIP in Context
      • Strategic issues
      • How VoIP works
      • Market issues
      • Interoperation with POTS
      • Interoperation among VoIP services
      • Strategic options
    • VoIP in Context
      • What context would that be ... ?
    • VoIP in Context
      • Strategic issues
      • How VoIP works
      • Interoperation
      • Strategic options
    • VoIP: Strategic Issues
      • Global or local scope?
      • Build, buy, or leave it to the users?
      • Proprietary or standards-based?
      • Branding?
      • First, see how it works ...
    • How VoIP works
      • Different flavours: Standards: SIP, H.323, Services: Skype, IP-TSPs
      • Similar requirements: Find called party Set up call
      • Look at SIP ...
    • SIP — direct call INVITE sip: 10.17.243.34 100 Trying - ACK RTP session (voice, video, etc) Artificially simple case: caller knows where my phone is Caller’s phone My phone 200 OK 180 Ringing - 192.168.19.76 10.17.243.34
    • SIP — where did he go? 10.17.243.34 Usual case: my phone is nomadic Caller’s phone My phone 10.97.1.5
    • SIP servers keep track 10.17.243.34 SIP Registrar: tracks last REGISTER event Caller’s phone My phone 10.97.1.5 SIP Registrar server sip.example.net Caller’s SIP server (if any)
    • SIP — using servers INVITE sip: [email_address] ACK RTP session (voice, video, etc) Servers broker call using SIP Payload is carried peer-to-peer INVITE INVITE 200 OK Control Transport Data
    • VoIP compared to e-mail Submit Difference: mail servers carry payload Forward Retrieve Message queue Message store Control & Data Transport
    • VoIP compared to POTS Place call Difference: Payload travels over provider’s resources Set up circuit Terminate call Voice traffic over circuit Vertically integrated: no separation of Control, Data, and Transport
    • Interoperation
      • Technology: gateways, mapping
      • Service management
      • Business model
      • POTS is centre-stage
    • Interoperation
      • Within POTS
      • VoIP/POTS
      • Within VoIP
    • POTS Interoperation
      • Dial plan what can be dialled (DTMF-12)
      • Numbering plan what can be reached (E.164)
      • Interconnection specific number ranges — routing codes
      • Cascaded charges terminating operator in control
      • Fewer hops best for business
      Originating Operator Terminating Operator Transit Operator
      • POTS dominates (Metcalfe’s Law)
      • Address (URL, number) mapping
      • Media conversion
      • Business relationship
      VoIP/POTS Interoperation
      • POTS uses [*#0-9] — VoIP side must accommodate
      • Customer aliases facilitate this — Real POTS phone number (E.164) — Two-stage dialling to “extension” — extension@example.org — username@example.org
      VoIP/POTS Address Mapping
      • Numbering plan POTS: numeric only VoIP: URL space or per-operator number blocks
      • Interconnection must map (relevant parts of) numbering plans POTS to VoIP: ENUM can find matching URL for number VoIP to POTS: configuration; ENUM enables POTS bypass
      • Successive gateways degrade quality due to lossy trans-coding
      VoIP/POTS Interoperation
      • Different business model
      • Cascaded charges on POTS side from POTS: gateway immediately (keep entire fee! from VOIP: exit to POTS late (keep bigger share of fee!)
      • Paradox: VoIP is good for operator!
      VoIP/POTS Interoperation
      • Dial plan DTMF (0-9, #, *) URL (user@domain)
      • Numbering plan URL space
      • Interconnection Configuration tables — maintenance! DNS is so much simpler ENUM: maps number to URL SPIT: Spam over IP Telephony
      • Reachability decoupled from cost
      VoIP Interoperation Originating IP-TSP Terminating IP-TSP Internet: ISPs & Transit
    • VoIP Interoperation
      • Can be just like e-mail: sip:user@domain
      • URL drives DNS to locate destination
      • DNS RR-types: SRV, A
      • Provider issues: — “walled garden” vs “public park”
      • Customer issues: NAT, firewalls
    • VoIP Interoperation
      • Technology open — just like e-mail
      • Operator business model varies — “walled garden” vs “public park”
      • Obstacles may be significant — NAT, firewall
    • VoIP Interoperation
      • Static routes support bilateral agreements
      • VoIP “islands” may need to route via POTS — involving duration charges, double transcoding
      • ENUM maps numbers to URLs — but not yet widely (enough) deployed
      • Not unlike e-mail before MX records
      • Example
        • [Remember “!” and “%” for e-mail]
        • *8 *4yy 8972xxxx
        • sip: 8972xxxx @example.org
        • sip:someuser@example.org
      Address Mapping
      • Encodes E.164 numbers as domain names — no “short codes” or “operator-specific”
      • Standard algorithm to determine URL — DDDS: RFC 3401ff
      • Not yet generally deployed
      ENUM
    • Strategic options
      • Global or local scope?
      • Build, buy, or leave it to the users?
      • Proprietary or standards-based?
      • Branding?
    • Local or global scope
      • Technology substitution
      • “Free” long-distance phone-calls
      • Extend footprint of internal PBX — teleworkers, conference-goers
    • Build, buy, or step aside
      • In-house like e-mail linked to other administrative processes
      • Outsource to existing IP-TSP established expertise
      • Skype — just works walled garden with gates (charged Skype-in, -out)
      • Gizmo — has free SIP-out
    • Standard or proprietary
      • Cisco, Nortel, ...
      • Skype
      • Standard Interoperability Exploits DNS for provisioning Open Source: SER, Asterisk
    • Branding
      • What goes on the stationery?
      • Skype: joe_user
      • IP-TSP: sip:Niall.oReilly.UCD@example.ie
      • Own-brand: sip:First.Last@ucd.ie
      • E.164: +353-1-716-xxxx
    • Strategic options
      • Global or local scope?
      • Build, buy, or leave it to the users?
      • Proprietary or standards-based?
      • Branding?
      • Know what you require, then decide
    • VoIP Resources
      • Terena VoIP Cookbook (2004)
      • Richard Stastny’s Blog http://voipandenum.blogspot.com
      • iptel.org
    • ?