In an enterprise's VoIP network, IP phone A registers with the U1981, and POTS phone B registers with the same U1981 through an IAD. During a call between phones A and B, which of the following…

Question

Options

• AThe flow for signaling streams is the same as that for media streams.
• BSignaling streams must traverse eSpace U1981, while media streams do not.
• CMedia streams are transmitted directly between IP phone A and the IAD.
• DIf eSpace U1981 fails (when the call between phones A and B has been continued for 5 minutes),

• A
  10% (5)
• B
  84% (41)
• D
  6% (3)

Explanation

In VoIP architectures, signaling (call setup/control messages like SIP/H.248) and media (the actual RTP audio) travel different paths. Signaling must always route through the eSpace U1981 softswitch because U1981 is the call controller responsible for establishing, managing, and tearing down calls - making B correct. Once the call is established, however, media streams bypass U1981 entirely and flow directly between the endpoints: IP Phone A sends RTP audio straight to the IAD (which converts it for POTS Phone B), making C correct.

Why A is wrong: Signaling and media streams explicitly follow different paths - signaling through U1981, media peer-to-peer between A and the IAD - so they cannot share the same flow.

Why D is wrong: Option D (though truncated) implies U1981 failure would drop an established call, but since media streams travel directly between endpoints and bypass U1981, an ongoing call's audio continues uninterrupted even if the softswitch fails mid-call.

Memory tip: Think of U1981 as a traffic controller at an intersection - it directs cars (signaling) to where they need to go, but once they know the route, the cars (media/RTP) drive directly to the destination without passing through the intersection again.

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