Source: No Jitter
Even something as newfangled as SIP carries with it the mustiness of ancient times.
I live in what has been called the last eastern city in the United States -- Saint Paul, Minnesota. Our houses are old (I live in a 109-year-old Victorian), our roads are curvy (we have avenues that intersect avenues), and quite a few of our gar
ages began their lives as horse barns. Still, despite the turn-of-the-last-century charm that can be found throughout the city, we do have electricity, indoor plumbing (albeit not always the best water pressure), and paved roads.
However, come spring and the winter thaw, potholes open up across the city that shed light on the city's less sophisticated and not too distant past. Take a look under the multiple layers of asphalt that blanket our streets and you will find red clay bricks or better yet, glacier-rounded cobblestones. While the tires on my car aren't particularly fond of these archeological finds, I love the seasonal glimpses we get into our city's past. I am reminded that what we think of as new and exciting today, will be seen as out-of-date and archaic tomorrow.
Take a good look at modern communications systems and protocols and you will uncover similar relics of history. Even something as newfangled as SIP carries with it the mustiness of ancient times. For example, every SIP request or response ends with a blank line. While this may not look all that odd if you were to visually inspect a SIP message, a packet tracing tool such as Wireshark shows you that a blank line is made up of two ASCII characters -- the carriage return (hexadecimal 0x0D) and a line feed (hexadecimal 0x0A).
Those of you old enough to have taken a typewriting class in high school will remember that when you reached the end of a line you would take hold of the return lever and throw it to the left. Not only did this bring you back to the margin (carriage return), it advanced the paper to the next line (line feed). This means that inside every single SIP message you have something that dates back to a mechanical procedure that originated in the early 1800s. So much for being cutting edge.