Computer network technology-CodePudding

Computer network technology professional (a) :

Information technology does not involve technology is () a. b. network technology computer technology c. d. communications

Information technology (it)
Definition 1: the application of relevant data and information technology. Its content includes: the collection of data and information, said the processing, security, the transmission, exchange, apparent, management, organization, storage, retrieval, etc. Subject: communications technology (level 1 subject); Communication principle and basic technology (secondary discipline)
Definition 2: the use of the electronic computer, remote sensing technology, modern communication technology, intelligent control technology, transmission, storage, display and application of information technology.
So I think choose D.

Computer network technology professional (2) :

Computer network technology calculation problem
820.3 1 km long, 10 MBPS LAN, the signal propagation velocity of 200 m/us, the data frame length is 256 (including 32 bit overhead). The first time after a successful send to receiver to capture the channel to send confirmation frame. A 32-bit hypothesis does not consider the conflict, q does not include the valid data overhead rate?

Including overhead rate is, from the sending and receiving confirmation the entire computing:
1) the time needed for sending data frames 256=256 bit/10 MBPS=25.6 us
The transmission of data frames on the channel time=1000 m/(200 m/us)=5 us
Sharing time=25.6 us + 5 us=30.6 us
2) send back to confirm the frame time needed for 32-bit=32 bit/10 MBPS=3.2 us
Confirm the frame on the channel transmission time=1000 m/(200 m/us)=5 us
Sharing time=3.2 us + 5 us=8.2 us
So the effective data transfer rate of (256-32) b/(30.6 + 8.2) us=5.77 Mbps
Does not include the overhead rate is
Time needed for sending data frames 256=256 bit/10 MBPS=25.6 us
The transmission of data frames on the channel time=1000 m/(200 m/us)=5 us
Sharing time=25.6 us + 5 us=30.6 us
So the effective data transfer rate of (256-32) b/30.6 us=7.3 Mbps

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