Binary packets

Your statement is a little ambiguous but I'm guessing this is an instance of question 15 in the forum FAQ

It's a little more complex than the FAQ makes it. Sending a struct isn't the best idea.

http://www.gpwiki.org/index.php/Binary_Packet
http://gpwiki.org/index.php/Optimizing_Your_Online_Game_Bandwidth

Both those tutorials will help you. Binary packets are very convenient and will save you a lot of time. Make functions in your game objects to serialize certain packet data. Using something like the below code is acceptable:
GameObjectArray[5].serializePosition(&packet);

Read over those two articles first. The first one is mine and I've only made one game. The bottom one is written by the creator of VBgore.

Quote:

Sending a struct isn't the best idea.

There are many popular games that "send structs" and work very well. It's a great way to get started. You only need to improve on that method when and if you determine you can't create an efficient protocol on top of structs.

And, when you improve, traditional stream serialization may or may not be the right direction to go in. Other approaches, such as state-ful compression or arithmetic coding, may give you a better overall improvement.

I agree that binary serialization is often useful, especially when you can combine it with knowledge of needed range and precision of different data elements, but it's not a given that it's always the right fit for any specific problem.