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5266
Views
5
Helpful
3
Replies
ereyes
Beginner

SIP Delayed media or Early media

Hi guys , I need know if this method is Delayed or early media signaling for SIP protocol.

Invite + SDP -->

100 Trying  <---

200 OK+ SDP <----

ACK --->

regards.

3 REPLIES 3
Daniele Giordano
Rising star

Sounds like a delayed media.

These are various examples of calls published on "Innovaphone" wiki.

Forward Negotiation

  1. INVITE with SDP-Offer
  2. 180 Ringing
  3. 200 OK with SDP-Answer
  4. ACK

Note: 180 Ringing does not contain an SDP-Answer!

Forward Negotiation with Early Media

  1. INVITE with SDP-Offer
  2. 183 Session Progress with SDP-Answer
  3. 180 Ringing with SDP-Answer
  4. 200 OK with SDP-Answer
  5. ACK

Note: 180 Ringing contains an SDP-Answer!

Reverse Negotiation

  1. INVITE
  2. 180 Ringing
  3. 200 OK with SDP-Offer
  4. ACK with SDP-Answer

Reverse Negotiation with Early-Media

  1. INVITE
  2. 183 Session Progress with SDP-Offer
  3. PRACK with SDP-Answer
  4. 180 Ringing with SDP-Offer
  5. PRACK with SDP-Answer
  6. 200 OK with SDP-Offer
  7. ACK with SDP-Answer

Re-Negotiation on an established call

Forward Negotiation

  1. INVITE with SDP-Offer
  2. 200 OK with SDP-Answer
  3. ACK

Reverse Negotiation

  1. INVITE
  2. 200 OK with SDP-Offer
  3. ACK with SDP-Answer

Regards.

need to confirm if it is delayed because I have a problem of interworking , I have a 2821 ip-ip h323 to Sip and does not work randomly, some calls are going  well and others give me cause release 127.

according to the specification,  FastStart to delayed media is not supported.  If I confirm that the signaling presented in the first sheet is delayed  confirming the problem would be.

Early Media and generally progress messages use a 183 response. In your sip session there aren't these type messages, so it is a delayed media.

See draft-rosenberg-sip-early-media-00.txt and draft-donovan-mmusic-183-00.txt

Regards.

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