Exam 2 Quiz Review Flashcards
Of Audio, Video, and Data transfers, which are examples of variable bit rate traffic?
Video & Data Transfers. Audio tends to be constant bit rate with each packet being of a small fixed size.
Beta = 100 kB, Rho = 10 packets/sec, T = 1 sec, packet size = 1 kB. What is the max rate in kilobits per second?
Beta + T * Rho
(100 + 1 * 10)*8 = 880kb
R(sus) = 10 Mbps, r = 15 Mbps, Beta = 1 MB, how long can sender send at r?
Beta = 8 Mb
8 Mb / (5 Mb/s) = 1.6 seconds
Can Flow and Packet monitoring provide Timing Information (packet-level), Packet Headers, and number of bytes in each flow?
NO. Only packet monitoring can help with timing information (packet-level) and packet headers. Both can determine the number of bytes in each flow.
What are some possible causes of congestion collapse?
Spurious retransmissions of packets in flight and undelivered packets are a common cause of congestion collapse.
What are some solutions to the TCP “Incast” Problem?
Using finer granularity timers and having fewer acknowledgments.
Which pathologies can streaming and audio/video tolerate?
Streaming audio/video can tolerate loss and delay, but has a hard time with variation in delay.
What are some commonly used Quality of Service techniques for audio/video?
Common QoS for streaming audio/video is to mark packets as higher priority and schedule so that it is service more frequently that applications that are lower priority.
Which HTTP header field indicates client software?
User-Agent is the HTTP header field that indicates client software.
What are some of the benefits of caching?
1) Reduced transit costs for the local ISP 2) Improved performance for local clients
Why do ISPs want to peer w/ CDNs?
Lower transit costs and better performance for customers. CDNs do not provide better security nor better predictability.
