Radia Perlman On SDN, IPv6 & Security

Radia Perlman is a legend in the networking industry, having invented the Spanning Tree Protocol (STP) and then improved on STP with TRILL (Transparent Interconnection of Lots of Links). With a PhD in computer science from MIT, she holds more than 100 patents and is currently a fellow at EMC. Perlman was the keynote speaker at the 2015 USENIX Annual Technical Conference, held this week in Santa Clara, Calif.

Her talk, "Network Protcols: Myths, Missteps and Mysteries" focused on the development of STP as well as her trust models for Public Key Infrastructure (PKI). But in her far-ranging discussion, she also expressed her opinion on some of the hot topics of the day, including software-defined networking and IPv6, the most recent version of the Internet Protocol. 

Perlman started her talk by encouraging audience members to think critically. "A lot of what everyone knows about networks is actually false," she said.

Buzzwords like SDN drive her crazy, Perlman said. Despite people in the industry describing SDN as revolutionary, she said she hasn't found anything new with SDN. "It's not a revolution in anything," she said. Perlman advised audience members that the buzzword is OK to use with customers, but not with engineers. "It terrorizes 80% of engineers," she said.

Buzzwords make networking confusing. One example is the assumption that security is built into IPv6, according to Perlman.  "The germ of truth is that there's one protocol called IPsec. It can work equally well with IPv4 or IPv6, but the spec says it's mandatory for IPv6 and optional for IPv4," she said. "It turns out there are more [IPsec] implementations for IPv4 than IPv6." 

She also noted that the Internet would have had 20-byte addresses if it had adopted ISO's CLNP (Connectionless Network Layer Protocol) back in 1992. "It's so much harder to change the Internet now," Perlman said.

On security, Perlman noted that there's always been a tradeoff between security and usability, but the industry has managed to make things both unusable and insecure.

"Engineers should actually meet some humans so they can stop having programs that ask questions like, 'Do you want to display both the secure and insecure items?'," she said.

Perlman said she doesn't want to hear that we need better user training. Drawing applause and laughter from an appreciative audience, she quoted from her book, Network Security: Private Communication In A Public World:

"Humans are incapable of securely storing high-quality cryptographic keys, and they have unacceptable speed and accuracy when performing cryptographic operations. They are also large, expensive to maintain, difficult to manage, and they pollute the environment. It is astonishing that these devices continue to be manufactured and deployed, but they are sufficiently pervasive that we must design our protocols around their limitations."

Perlman expressed disdain for standards bodies, which she said are more like "drunken sports fans" rather than careful deliberators. 

While Perlman isn't a fan of buzzwords like SDN, she was more hospitable towards a couple of other terms used widely in the industry today.

During a question and answer period after her keynote, Perlman said she thinks cloud is actually a meaningful term. "I'm a firm believer in virtualization and the cloud," she said. She also said Network Functions Virtualization (NFV) is "well-defined."

Image: Perlman was named a "Pioneer" by the Internet Hall of Fame in 2014.