Default IMS signaling bearer uses which QCI?

Interview
1

Q. Default IMS signaling bearer uses which QCI?

a) 5
b) 9
c) 2
d) 1

Check 🔎

:arrow_right: Correct answer: Letter a.

The default bearer used for IMS signaling (i.e., SIP messages between UE and P-CSCF) uses QCI 5.

  • QCI 5 is standardized in 3GPP for IMS signaling traffic.
  • It provides guaranteed bit rate (GBR) with low latency and high priority, ideal for real-time signaling.
  • Bearers using QCI 5 are established upon successful IMS registration.

Q. Default IMS signaling bearer uses which QCI?

a) :white_check_mark: 5
→ Correct. QCI 5 is specifically reserved for IMS signaling traffic. QCI 5 is designated for IMS SIP.

b) :x: 9
→ Incorrect. QCI 9 is for default bearers (non-IMS), typically internet/data traffic.

c) :x: 2
→ Incorrect. QCI 2 is used for conversational video, not signaling.

d) :x: 1
→ Incorrect. QCI 1 is used for IMS voice (VoLTE) media bearer, not signaling.