An engineer Is troubleshooting an MWI Issue between Unity Express and CallManager Express. In the debug SIP logs, the engineer can see CallManager Express responding to Unity Express with a 488 Not…

Question

Options

• AEnsure that codec G.722 Is configured In the dial peer.
• BEnsure that codec G.711ulaw is configured in the dial peer.
• CEnsure that codec G.711alaw is configured In the dial peer.
• DEnsure that codec G.729 is configured In the dial peer.

• A
  5% (1)
• B
  81% (17)
• C
  5% (1)
• D
  10% (2)

Explanation

A '488 Not Acceptable Here' SIP response indicates a codec negotiation failure - the two endpoints cannot agree on a common media format. MWI (Message Waiting Indicator) notifications between Cisco Unity Express (CUE) and Cisco Unified Communications Manager Express (CUCME) use SIP, and the SIP dial peer on the CUCME side must specify a codec that CUE supports. For North American deployments, G.711ulaw (mu-law) is the standard codec. If the dial peer is configured with G.711alaw (A-law, used in Europe), G.722 (HD audio), or G.729 (compressed), and CUE only offers G.711ulaw in its SDP, CUCME will respond with 488. Configuring 'codec g711ulaw' on the relevant dial peer resolves the mismatch.

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