Define/Encode/Serialize

Once upon a time, packing the structure construct defined in C was considered as an art of programming. Literally all the signalling protocol simulators I worked with had this one cryptic piece of packing and unpacking the message. 

Now a days it is much more convenient with all the different efficient methods. In fact most of them come with the underlying RPC mechanism too. Below are some, which can be used.  

1. Google Protocol Buffers. 

https://developers.google.com/protocol-buffers/docs/overview

2. Facebook Thrift 

http://thrift-tutorial.readthedocs.org/en/latest/intro.html

3. Cap'n Proto 

https://capnproto.org/

For XML lovers, I am sure you know where and what to look for :)