Refer to the exhibit. An administrator is troubleshooting why users are not hearing audio when dialing long distance numbers across their Cisco Unified Border Element. The customer's carrier has a req

Question

Options

• AEnable PRACK.
• BEnable Early Offer on the Cisco Unified Border Element.
• CEnable the supplementary-service media-renegotiate command.
• DEnable Media Flow Around.
• EEnable Mid-Call Signaling Consumption.

• A
  70% (26)
• C
  5% (2)
• D
  16% (6)
• E
  8% (3)

Explanation

Enabling PRACK (RFC 3262) and Early Offer together solves the root cause: the carrier needs to send early media (a tone or prompt for the access code) before the call is fully established, and CUBE must support reliable provisional responses (PRACK) and include SDP in the initial INVITE (Early Offer) so the media path exists to carry that early audio. Without Early Offer, CUBE's default Delayed Offer withholds SDP until call completion, meaning the carrier has nowhere to send the access-code prompt; without PRACK, the carrier's 183 Session Progress (with early SDP) is unacknowledged, so early media never flows.

Why the distractors are wrong:

• C (supplementary-service media-renegotiate) enables re-INVITE handling for mid-call services like hold/transfer - not relevant to initial media negotiation with a carrier.
• D (Media Flow Around) bypasses CUBE's media handling entirely, which doesn't fix the signaling mismatch and can break carrier interoperability.
• E (Mid-Call Signaling Consumption) governs how CUBE handles mid-call DTMF events internally - it doesn't resolve the early-media establishment failure.

Memory tip: Think "PRACK + Early Offer = Early Audio." When a carrier needs interaction before the call completes (access codes, IVR prompts), you need Early Offer to put SDP in the INVITE and PRACK to reliably acknowledge the carrier's early responses - both are required for that audio channel to exist in time.

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