2.2 Troubleshoot Elements of a SIP 350-801 Practice Questions (Page 4)

Questions 16–20

1. 16foundation · easy

   In an SDP body within a SIP message, which line specifies the IP address and port where the endpoint expects to receive media?

   • Aa= line
   • Bc= line
   • Co= line
   • Dm= line
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2. 17application · medium

   A user hangs up a call, but the remote party's phone continues to show the call as active for several minutes before finally clearing. A SIP trace shows the BYE was sent from the user's phone, but no response was ever received. What is the most likely reason the remote phone did not clear the call?

   • AThe remote phone never received the BYE because it was lost in transit and no retransmission occurred.
   • BThe remote phone was waiting for a re-INVITE before it would accept the BYE.
   • CThe user's phone sent a CANCEL instead of a BYE, which only works for unanswered calls.
   • DThe BYE was sent with the wrong Call-ID, so the remote phone ignored it.
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4. 18foundation · easy

   During SIP call setup, which message is sent by the UAS to the UAC to indicate that the INVITE was received and the call is being processed, but no final response has been generated yet?

   • A183 Session Progress
   • B180 Ringing
   • C100 Trying
   • D200 OK
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5. 19application · medium

   A video call between two Cisco endpoints fails to establish video, though audio works. The SDP offer from the calling endpoint contains `m=video 49172 RTP/AVP 96` and `a=rtpmap:96 H264/90000`. The answer from the called endpoint contains `m=video 0 RTP/AVP 96`. What is the most likely reason video is not working?

   • AThe called endpoint selected a different H.264 profile that is incompatible with the offer.
   • BThe calling endpoint forgot to include the `a=sendrecv` attribute for the video stream.
   • CThe called endpoint rejected the video stream by setting the port to zero in the answer.
   • DThe RTP payload type 96 was not registered in the answer's rtpmap, so the codec could not be used.
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6. 20foundation · easy

   In an SDP offer, which attribute is used to indicate support for DTMF relay via RFC 2833/4733?

   • Aa=ptime:20
   • Ba=rtpmap:101 telephone-event
   • Ca=sendrecv
   • Da=fmtp:101 0-15
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