Compressing SIP

1
Early Media SIPPING WG
Gonzalo.Camarillo_at_ericsson.com
2
Status

• draft-camarillo-sipping-early-media-01.txt
• Current version captures long WG discussions
• Gateway model vs application server model
• There is consensus on the draft
• But still one important open issue
• Addition of a there is media coming or a do
  not generate local ringback flag to 180
  responses
• Is it really needed?

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No Flag is Defined

• 180 is received
• The MGC does not know if there will be in-band
  alerting
• MGC -gt MG Generate local ringback until media
  arrives
• 180 without the flag is received
• MGC -gt MG Generate local ringback until media
  arrives
• 180 with the flag is received
• MGC does not send any message to the MG

A Flag is Defined
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Scenarios with Tight Coupling Between Media and
Signalling

• No media accepted until 200 OK (or 180 with the
  flag) arrives
• No need to implement media detection
• Media clipping is not a problem
• Should the WG even consider this scenario?