| verbose, weak verbs, bad | short, strong, good |
|---|---|
| make assumption | assume |
| is a function of | depends on |
| is an illustration | illustrates, shows |
| is a requirement | requires, need to |
| utilizes | uses |
| had difference | differed |
Note that abbreviations for organizations do take a definite article, as in "The IETF standardized TCP."
Since the "P" in TCP, UDP and similar abbreviations already stands for "protocol", saying the "the TCP protocol" is redundant, albeit common. (LCD, Liquid Crystal Display, is another common case where many are tempted to incorrectly write LCD display. Indeed, Google references 2,060,000 instances of that usage.)
In general, hyphens are used
its with it's (it is).
There are two service models, integrated and differentiated service. Integrated service follows the German approach that anything that isn't explicitly allowed is verboten. It strictly regulates traffic, but also makes the trains run on time. Differentiated service follows the Animal Farm appraoch, where some traffic is more equal than others. It seems simpler, until one has to worry about proletariat traffic dressing up as the aristocracy.
Etc.: Not to be used of persons. Equivalent to and the rest, and so forth, and hence not to be used if one of these would be insufficient, that is, if the reader would be left in doubt as to any important particulars. Least open to objection when it represents the last terms of a list already given in full, or immaterial words at the end of a quotation. At the end of a list introduced by such as, for example, or any similar expression, etc. is incorrect.
Fig.~\ref{fig:arch}