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Oct 15

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CCNP Voice Notes – Dials Peers and Matching OH MY!

Inbound Dial Peer Matching
3 elements in call setup message:

  1. Called Number (DNIS)
  2. Calling Number (ANI)
  3. Voice Port – port the call is coming in on
Plus 5 configurable dial peer attributes processed top down only if one above fails to match:
  1. Called number with incoming called-number.
  • Tries matching on DNIS if multiple longest match wins (YAY)
  • Calling number with answer-address.
    • Tries matching on ANI again if multiple longest match wins.
  • Calling number with destination-pattern.
    • Tries to match DNIS to destination-pattern (think route pattern) if multiple yada yada.
  • Voice-port associated with the port parameter.
    • Tries to match on port parameter if multiple dial peer first added in the config wins.
  • Last ditch, default dial peer.
  • *NOTES*
    Use the answer-address command when matching the region of a caller, recommended situations:
    • Callers from a given country should be directed to an appropriate group.
    • Directing callers from a specific region to a regional support group.
    Use the incoming called-number command whenever possible. All call setup messages include DNIS.
    Outbound Dial Peer Matching
    When a call arrives at a voice gateway, it uses the incoming dial string to match the destination-pattern on the outbound dial-peer. Once a match is found the port on POTS dial peers or session-target on VoIP dial peers is used to forward the call. MOST SPECIFIC MATCH WINS

    Default Dial Peer (Don’t be sad little guy you’re important too)
    Default dial peer referred to as dial-peer 0 (sounds ominous) it is used if no inbound dial peer can be matched, see list above. ONLY USED FOR INBOUND NEVER EVER EVER, (DON’T EVEN THINK IT) used for outbound. Characteristics of DP0 (Dial peer 0, DP0 sounds even more ominous) cannot be changed.
    DP0 VoIP Characteristics
    • G.729 / G.711
    • IP precedence set to 0.
    • VAD enabled
    • RSVP not supported
    • Fax-rate service supported
    DP0 POTS Characteristics
    • No applications supported
    • No DID support
    Avoid using DP0 when possible.

    Permanent link to this article: http://tripplehelix.net/ccnp-voice-notes-dials-peers-and-matching-oh-my/

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