Is TCP Past It?
And they’re also keen to hang onto protocols as long as possible, assuming that these protocols are still basically working – again a very sensible approach that complies with the First Law of Rural Mechanics (“if it ain’t broke, don’t fix it”).
Take the routing protocols OSPF (Open Shortest Path First) and BGP (Border Gateway Protocol), for instance. There have been several suggestions that these be completely revamped to meet the new challenges of the Internet, and these have been strongly resisted by the Internet Engineering Steering Group (IESG) hierarchy, down through the Internet Engineering Task Force (IETF) working groups. To be fair, it’s not easy to design good routing protocols, and the argument used is generally that the newer proposals don’t offer sufficient advantages over OSPF and BGP to warrant the disruption that the migration would cause.
But in the case of one stalwart IP protocol I think the case is becoming pretty watertight. It’s time to pension off the Transmission Control Protocol (TCP) for something better. It works tolerably well at the moment, but mark my words, in a few years' time trade journalists will be writing articles predicting the end of civilization as we know it, all because TCP is past it.
To put things in perspective, my view is this: Most users see adequate throughput from TCP applications today. So we don’t need to panic just yet. But power users are already seeing performance bottlenecks with the protocol, and that means that us mainstream folks will see those same problems in four or five years.
I’ve explained these problems in a Report that is being published concurrently with this column.
I believe one conclusion is unavoidable. The ultimate solution to this problem is to replace TCP with something else – TCPv2 if you want to call it that for nostalgic reasons. This means that we have to change software in IP host computers. In fact, it’s a problem on a similar scale to the IPv4 to IPv6 migration, and we know how much progress that’s made in the past 10 years.
There are lots of people working on this problem, but I think the time is right to open the debate a bit more widely than the Internet community – out to some of the folks who will need to start preparing for this migration when it finally comes about.
So if you’re seeing TCP performance issues today, let us know. If you’re working on TCP performance enhancements, why not tell us how things are going? You can do this by posting on the message board attached to this article, or by sending information to me at [email protected]. Please put “TCP Input” in the subject field so I can find it easily.
Hopefully, by sharing information with the people who are going to be working hard to implement the future migration, we can make sure it happens as smoothly as possible.
— Geoff Bennett, Director, Light Reading University