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NBN Co currently offers two analog voice ports (called UNI-V) on its Customer Premised Equipment (CPE) for fibre based services. [15 Marks: 1 + 2 + 2 + 8 + 2]

•What signaling protocol does the UNI-V use between CPE and access provider?

•What codec does the UNI-V use?

•What is the packetisation rate for the codec?

•What method(s) does NBNCo use to ensure QoS for UNI-V traffic traversing its network?

•What levels of QoS are there?




5. With the appropriate use of diagrams and clear descriptive text: [5 Marks]

•Consider a home router that is forwarding packets out of the house over a link that carries 12Mbit/sec downstream and 1Mbit/sec upstream at the IP layer. How many two-way RTP-based VoIP calls, using standard G.711a codecs, could be active at the same time between the house and outside world? (Assume standard VoIP encapsulation)



3. Imagine you have a standard web server containing a movie segmented into chunks and encoded at constant bitrates of 200, 500 and 1000 Kbps. Assume an additional 320 bytes of HTTP response overhead is required to encapsulate and send each chunk in response to GET requests from a DASH client. A single DASH client is connected to this server over a path exhibiting 350ms RTT and offering 16000Kbps in each direction at the IP layer. With the appropriate use of diagrams and clear descriptive text: [20 Marks: 2 + 6 + 12 ]

•What is the path's BDP?

•Assume the TCP layer's MSS is 1460 bytes, how long would it take for the DASH server's TCP layer cwnd to reach and exceed BDP during Slow Start from an initial window (IW) of 10 MSS?

•If the TCP stack at the DASH server begins in Slow Start with IW=10 MSS for the transmission of every chunk, how long does it take to transmit HTTP-encapsulated 4-second chunks encoded at the three representation rates? (Assume no packet losses or packet reordering along the path.)

    • 5 years ago
    • 20
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