Category: Internet

My friend Stretch alerted me to an article published by BBC News, which reports that “an EU cyber security expert” told “a House of Lords committee” (wow, that’s the perfect body to deal with Internet issues) that the proposal submitted by Chinese to an ITU-T study group required “modifications to BGP” which would “threaten the stability of the entire Internet.”

Regardless of whatever the original proposal has been, the information has been distorted, twisted, adapted, abstracted, and misunderstood so many times before being published that it’s impossible to figure out what exactly has been going on. The account of an eyewitness (sitting in the Kampala talks in September) doesn’t tell much more.

ITU (the organization formerly known as CCITT) is having a bit of a relevance problem these days: its flagship technological achievements, including X.25, ISDN, ATM, and SDH, are dead or headed toward oblivion … and a former pariah, a group of geeks, is stealing the show and rolling out the Internet. No wonder their bureaucrats are having a hard time figuring out how to justify their existence. For years they’ve been lamenting how much they’ve contributed to the Internet (highly recommended reading for Monty Python fans) and how their precious contributions were unacknowledged. Now they came forth with a “wonderful” idea: the history of IPv4 address allocation proves that the wealthy nations and early adopters managed to grab disproportionate parts of the IPv4 address space (well, that’s true), so they made it their mission to protect the poor and underdeveloped countries in the brave new IPv6 world. In short, they want to become an independent address allocation entity (RIR). It looks like another worldwide bureaucracy is precisely what we need on top of all the other problems we have with IPv6 deployment.

As expected, my “the socket API is broken” post generated numerous comments, many of them missing the point (for example, someone scolded me for quoting Wikipedia and not the official Linux documentation). I did not want to discuss the intricate technical details of the various incarnations of the API but the generic stupidity of having to deal with low-level networking details in the application.

Fabio was kind enough to provide the recommended method of using the Socket API from man getaddrinfo, effectively proving my point: why should every application use a convoluted function when all we want to do (in most cases) is connect to the server.

Patryk went even further and claimed that the socket API provides “basic functionality” and that libc is not the right place for anything more. Well, that mentality caused most of the IPv4-to-IPv6 application-related issues: obviously the applications developed before IPv6 was a serious consideration had to be rewritten because all the low-level code was embedded in the applications, not isolated in the library. A similar problem has effectively stalled SCTP deployment.

However, these are not the only problems we’re facing today. Even if the application properly implements the “try connecting to multiple addresses returned by DNS” function, the response time becomes unacceptable due to the default TCP timeout values coded in various operating systems’ TCP stacks.

Someone really wants to hear my opinion on SCTP (RFC 4960); he’s added a “what about SCTP” comment to several Internet-related posts I wrote in the last weeks. So, here are my totally unqualified (I have no hands-on experience) thoughts about SCTP.

Let me reiterate: I’m taking a 30,000-foot perspective here and whatever I’m writing could be completely wrong. If that’s the case, please point out my mistakes in your comments.

From the distance, the protocol looks promising. It provides datagram (unreliable messages), reliable message (record) and stream transport. Even more important, each connection can run across multiple IP addresses on each endpoint, providing native support for scalable IP multihoming (where each multihomed host resides in multiple PA address blocks from various Service Providers).

You might think that the lack of a decent session layer in the TCP/IP protocol suite is the main culprit for our reliance on IP multihoming and related explosion of the IP routing tables. Unfortunately, we have an even bigger problem: the Berkeley Socket API, which is around 40 years old and used in almost all TCP/IP software implementations and clients (including high-level scripting languages like PERL or Python).

One of the biggest challenges facing the Internet core today is the explosion of the IP routing and forwarding tables, which is caused primarily by traffic engineering and multihoming requirements. Things were supposed to get better when IPv6 introduced strict hierarchical addressing (similar to the phone number addressing, where the first few digits always denote the country code).

Unfortunately, the hierarchical IPv6 addressing idea relied on incredible belief that the world will shape itself according to the wills of the IETF working group members. Not surprisingly, that didn’t happen and the hierarchical IPv6 addressing idea was quietly scrapped, giving us plenty more prefixes to play with when trying to pollute the global IPv6 routing tables.

The discussions following my “All-I-can-eat mentality” post have helped me get a much better understanding of the broadband access business issues. I’ve already shared some of them in a follow-up post. A few weeks later (just before leaving for my summer vacation) I’ve tried to provide as balanced perspective as I could manage in the “Broadband traffic management: Finding rational solutions to ease congestion” article I wrote for SearchTelecom.

In one of our discussions, Stretch provided an excellent graph illustrating that the ISP competition seems to reduce prices almost linearly and asked me in a later comment to justify the inverse relation between subscription charges and consumer choice.

You might consider this debate to be purely between Stretch and myself, but it’s an interesting example of what you might need to do in daily your job. If you want to be a great networking engineer, you have to be prepared to question everything, including common wisdoms, “well-known truths”, “common practices” and facts that look too good to be true. Ready? Let’s go …

The “All-I-can-eat-mentality” article has triggered (as expected) numerous responses. Some of them provided useful data, links to more information or informative perspectives – many thanks to those readers. A few others were unfortunately following the “I-am-right” line without considering facts. Most of the readers from the Service Provider community decided to stay anonymous (when you read all the comments, it becomes obvious they made a wise decision) or respond off-line.

Whatever your position in this issue, I would like to ask you to keep your comments focused on the topic. Although you were all infinitely more polite than the usual forum/blog crowd and provided some really good arguments, writing angry replies does not help. What’s happening with Internet is (like it or not) our common problem … or you could take the blue pill and continue bashing the other side.

I particularly liked the summary of our discussion posted on Slashdot (where someone included the link to my blog):

Whoa, whoa, whoa, that article seems to be promoting a balanced viewpoint that denies a) that telcos are totally evil and b) that we should all be allowed to have as much bandwidth as we want and not have to pay for it. We'll have none of that nonsense on /.

We all know that the global BGP table is exploding (see the Active BGP entries graph) and that it will eventually reach a point where the router manufacturers will not be able to cope with it via constant memory/ASIC upgrades (Note: a layer-3 switch is just a fancy marketing name for a router). The engineering community is struggling with new protocol ideas (for example, LISP) that would reduce the burden on the core Internet routers, but did you know that we could reduce the overall BGP/FIB memory consumption by over 35% (rolling back the clock by two and a half years) if only the Internet Service Providers would get their act together.