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IMS : Why P-CSCF node can not send message directly to S-CSCF ?

+3 votes
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Why P-CSCF node can not send message directly to S-CSCF ? What could be the reason behind it ?
I observed that S-CSCF node can send SIP messages to P-CSCF directly but why P-CSCF can not do towards the S-CSCF ?

posted Oct 29, 2015 by Alok

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1 Answer

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There could be one reason what I know that if SIP message doesn't carry Serve-Route information i.e. the address of S-CSCF , After receiving the SIP message at the P-CSCF, it forwards the SIP message to to I-CSCF. I-CSCF checks with HSS to get the relevant S-CSCF address.

I

answer Oct 30, 2015 by Harshita
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