Individual homework due next class October 26th.
- Determine the number of bits a geosynchronous satellite link may contain if we know the data-rate is 1Mbps and ground station is located in the equator line. (Remember)
- Same as before but if ground station is located in Valencia.
- Two hosts are communicated through a path containing three intermediate routers. If all links' rate is 1Mbps. How long does it take for a 78 KByte file transmitted from one host to be fully received at the other end if packet size is 512 bits.
- Using the link of problem one, how long does it take for the ground station to upload a 78 KByte file to the satellite (maybe a software update) if packet size is 512 bits and a 20 bits acknowledgment packet has to be send back (and received) before a new data packet can be transmitted?
Can I get any hints for the first 2 questions? mainly what are you asking(theoretically speaking). I understand that we know the distance as it is geostationary and that changing the location of the station changes this distance but apart from that I'm very lost.
ReplyDeleteExercise number 2 requires you to do some extra math involving the latitude and longitud of Valencia http://www.longitude-latitude-maps.com/city/200_927,Valencia,Valencia,Spain and the location of the satellite (which is not was not given in the exercise).
ReplyDeleteTherefore you need to fix the satellite location first, somewhere over the equator line (you can chose a spot close to Sao Tome and Principe) to get the closest distance possible. Or you select any other spot of your choice.
Me temo que faltan datos en el ejercicio 3, no se puede resolver.
ReplyDeleteAnd what info do you think it is missing? (whatever is not mentioned you can consider it negligible).
ReplyDeleteSon varios datos los que faltarían, pero el más significativo sería la longitud de cada uno de los enlaces, dado el pequeño tamaño del archivo. Solo con que el retraso total de propagación fuera de 150ms (un enlace típico Europa-Asia-América del sur, suponiendo solo 3 routers), el resultado se incrementaria en más de un 20%, un porcentaje nada despreciable.
ReplyDeleteWhat if you consider the link distance to be short enough to be negligible (ie. it all can happen in the same room).
ReplyDeleteDe acuerdo, pero sería razonable decirlo en el enunciado.
ReplyDelete