fzakharov
26-05-2014, 19:31
Задачка 1.23 из книги "Computer Networks: A Systems Approach Fifth Edition"
Assume you wish to transfer an n B file along a path composed of the source, destination, 7 point-to-point links, and 5 switches.
Suppose each link has a propagation delay of 2ms and a bandwidth of 4 Mbps, and that the switches support both circuit and packet switching.
Thus, you can either break the file up into 1-KB packets or
set up a circuit through the switches and send the file as one contiguous bitstream.
Suppose that packets have 24 B of packet header information and 1000 B of payload, store-and-forward packet processing at each switch incurs a 1-ms delay after the packet had been completely received, packets may be sent continuously without waiting for acknowledgments,
and circuit setup requires a 1-KB message to make one round trip on the path, incurring a 1-ms delay at each switch after the message has been completely received. Assume switches introduce no delay to data traversing a circuit. You may also assume that filesize is a multiple of 1000 B.
(a) For what filesize n B is the total number of bytes sent across the network less for circuits than for packets?
Интересует её решение в mathCAD.
Свое решение представил тут: http://net-of-mine.blogspot.ru/2014/05/computer-networks-exercises-123-a.html
Но мне оно не очень нравится, может есть способ элегантнее?
Assume you wish to transfer an n B file along a path composed of the source, destination, 7 point-to-point links, and 5 switches.
Suppose each link has a propagation delay of 2ms and a bandwidth of 4 Mbps, and that the switches support both circuit and packet switching.
Thus, you can either break the file up into 1-KB packets or
set up a circuit through the switches and send the file as one contiguous bitstream.
Suppose that packets have 24 B of packet header information and 1000 B of payload, store-and-forward packet processing at each switch incurs a 1-ms delay after the packet had been completely received, packets may be sent continuously without waiting for acknowledgments,
and circuit setup requires a 1-KB message to make one round trip on the path, incurring a 1-ms delay at each switch after the message has been completely received. Assume switches introduce no delay to data traversing a circuit. You may also assume that filesize is a multiple of 1000 B.
(a) For what filesize n B is the total number of bytes sent across the network less for circuits than for packets?
Интересует её решение в mathCAD.
Свое решение представил тут: http://net-of-mine.blogspot.ru/2014/05/computer-networks-exercises-123-a.html
Но мне оно не очень нравится, может есть способ элегантнее?