It is important to consider the part that the SRS plays in the total project plan, which is dened in IEEE Std
610.12-1990. The software may contain essentially all the functionality of the project or it may be part of a
larger system. In the latter case typically there will be an SRS that will state the interfaces between the
system and its software portion, and will place external performance and functionality requirements upon
the software portion. Of course the SRS should then agree with and expand upon these system requirements.