PVID0 Specifications

As we have already seen it before , if the voice gateway is unable to match an inbound leg for the call , your call will take the properties of the PVID0 .

Don’t forget that you can’t update any properties if the PVID0 is hitted .

Let’s review then the specificities of this default dial-peer:

For POTS dial-peer

  • No IVR applications possible

For VOIP dial-peer

  • Any codec
  • fax-rate voice
  • ip precedence 0
  • No Resource Reservation Protocol ( RSVP)
  • VAD enabled

Inbound Dial Peer leg matching order

When a voice gateway receive a call , you can divide your call in an inbound and outbound leg.

Let’s see how the inbound priority matching .

  1. incoming-called-number (called number “DNIS” information used)
  2. answer-address (calling number “ANI” information used)
  3. destination-pattern (calling number “ANI” information used)
  4. voice-port (that has dial port configured)

Header

Depending the Layer 2 technology that you use , the header can change :

  • Ethernet Frame               => 18 bytes
  • Frame Relay/FRF.12          =>   6 bytes
  • MLP => 6 bytes  13 bytes
  • ATM => 5 bytes
  • MLP over Frame Relay => 14 bytes

For Layer 3 , you can use the following values

  • IP Header = 20 bytes
  • UDP Header = 8 bytes
  • RTP Header = 12 bytes

So it gives you the following amount

  • IP+TCP+UDP Header => 40 bytes

With CRTP enabled, you can then benefit of a huge saving of compression of this payload.
Indeed , from 40 bytes , you can decrease this payload from 2 up 4 bytes.

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