While opening a connection, the initial sequence number is to be derived using a time-of-day (ToD) clock that keeps running even when the host is down. The low order bits of the counter of the ToD clock is to be used for the initial sequence numbers. The clock counter increments once per milliseconds. The maximum packet lifetime is given to be s.
Which one of the choices given below is closest to the minimum permissible rate at which sequence numbers used for packets of a connection can increase?
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Answer: A
To prevent sequence number wrap-around and avoid collisions with older packets still circulating in the network, the sequence numbers must not be reused within the maximum packet lifetime ().
The maximum packet lifetime is given as:
To ensure that sequence numbers are unique and do not overlap within this duration, the minimum rate of sequence number increase () must satisfy the condition that at least one unique sequence number is allocated over the span of the maximum packet lifetime :
Substituting the given value of :
Among the given choices, /s is the closest to this minimum permissible rate.
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