top button
Flag Notify
    Connect to us
      Facebook Login
      Site Registration

Facebook Login
Site Registration

VoLTE : What are the roles for P-CSCF, I-CSCF and S-CSCF nodes during establishing voice call ?

+2 votes
VoLTE : What are the roles for P-CSCF, I-CSCF and S-CSCF nodes during establishing voice call ?
posted Oct 22, 2015 by Harshita

Share this question
Facebook Share Button Twitter Share Button LinkedIn Share Button

1 Answer

+1 vote

P-CSCF is the edge node of IMS network. I meant to say this is the first node to which an UE contacts (SIP registration).
Apart from involving in SIP registration, P-CSCF does the following jobs as well:
1- IP security association between UE and network.
2- Compression and decompression of SIP messages for the better utilization of available radio resources at eNodeB.

I-CSCF contacts HSS node to get the appropriate S-CSCF node of the network to forward the SIP request message.Sometime HSS provides a list of available S-CSCF nodes and I-CSCF selects one of them.

S-CSCF is the actual node which provides VoLTE services to its subscriber. This node also finds out the PGW address of second party of VoLTE call. I meant to say, receiver of the call.

answer Oct 24, 2015 by Vimal Kumar Mishra
Similar Questions
+3 votes

Is it possible HSS belongs to home network and S-CSCF belongs to visited network for the Cx interface ? If not then why ?

+2 votes

During Roaming in Volte/IMS Home Network Proxy-Call Session Control Function (P-CSCF) will be used or visited network ?

+4 votes

Sometimes due to coverage hole issue in the LTE network, the ongoing VoLTE is continued to UE by using the CS network like GSM network. This is known as SRVCC (Single Radio Voice Call continuity). What messages are exchanged between network nodes when UE moves from LTE to GSM ?

Contact Us
+91 9880187415
#280, 3rd floor, 5th Main
6th Sector, HSR Layout
Karnataka INDIA.