Susan Estrada
1988 – Founder of CERFnet, one of the original regional IP networks, and one of the architects of the Commercial Internet Exchange, the 1991 interconnection that let commercial Internet traffic flow legally for the first time. Her handshake helped end the era when business packets were banned from the backbone.
Summary of Contributions (50 words)
Susan Estrada founded CERFnet in 1988, building Internet service across California’s research community, then joined PSINet and UUNET’s AlterNet in forming the Commercial Internet Exchange in 1991, the first settlement-free commercial Internet interconnection. Her 1993 book Connecting to the Internet taught the public how to get online.
Impact (200 words)
Estrada’s impact sits at the exact seam where the research Internet became the commercial Internet. In 1988 she founded CERFnet, the California Education and Research Federation Network, operated out of General Atomics alongside the San Diego Supercomputer Center, and built it into one of the significant regional IP networks, connecting universities, research institutions, and, increasingly, companies that wanted on.
The problem was that the NSFNET backbone’s Acceptable Use Policy prohibited commercial traffic. A business could buy a connection and still find its packets unwelcome on the national fabric. In 1991 Estrada’s CERFnet joined Bill Schrader’s PSINet and Rick Adams’s AlterNet in creating the Commercial Internet Exchange, a router and an agreement: the member networks would exchange each other’s commercial traffic freely, settlement-free, no per-packet accounting, routing around the AUP entirely. It was the first legal home for commercial Internet traffic, and it proved the model, networks interconnecting as peers under simple flat agreements, that the entire commercial Internet later adopted.
Four years before the NSFNET restrictions ended on April 30, 1995, the CIX had already demonstrated the ending. Commerce did not wait for permission; it built its own exchange, and Estrada was one of the three people who built it.
Influence (200 words)
Estrada’s influence runs through the interconnection economics of the modern Internet. The CIX’s founding terms, flat fee, settlement-free, multilateral exchange, became the philosophical ancestor of the peering agreements that now stitch together tens of thousands of autonomous systems. The argument the CIX won, that networks should exchange traffic as peers rather than meter each other like long-distance carriers, is the reason the Internet’s economics diverged from telephony’s, and it remains the default worldwide.
Her influence also worked through the industry’s early institutions. CERFnet was a charter member of the regional network movement that carried academia onto IP, and Estrada was active in FARNET, the federation of those networks, as the community negotiated the transition to commercial service.
Then she influenced the demand side. Connecting to the Internet, published by O’Reilly in 1993, was among the first buyer’s guides for ordinary people and organizations trying to get online, plain answers about modems, providers, and connection types at the exact moment the public rushed in.
Her influence extends across:
- settlement-free peering culture, descending from CIX terms
- the regional-to-commercial transition of the early 1990s
- early ISP market formation in California and nationally
- consumer Internet adoption, through her O’Reilly guide
- later broadband advocacy, through her FirstMile.US last-mile work
Reach (200 words)
Estrada’s reach begins regionally and ends in the global fabric. CERFnet served hundreds of institutional customers across California and beyond, universities, labs, and early commercial subscribers, and was among the networks that made IP service a purchasable product rather than a government privilege. The CIX’s reach was categorical rather than large: every commercial packet that crossed it moved through a door that had not existed before 1991, and the interconnection model it pioneered now underlies the exchange points, from Amsterdam to Ashburn to Singapore, where the world’s networks meet.
Her book reached the public in multiple editions and translations during the Internet’s steepest adoption curve, guiding individuals, schools, and small businesses through their first connections.
Her reach extends through:
- the peering and exchange-point ecosystem built on CIX precedent
- California’s research and education community, wired by CERFnet
- the early commercial ISP industry the CIX made viable
- first-generation Internet users taught by Connecting to the Internet
- communities served by her later last-mile broadband advocacy at FirstMile.US and Aldea Communications
She served on the Internet Society’s board of trustees and was inducted into the Internet Hall of Fame in 2014, recognized among the builders who moved the Internet from grant-funded experiment to open market.
Innovation (200 words)
Estrada’s innovations include:
- CERFnet, one of the original regional IP networks, founded 1988 and run as a working service business
- co-founding the Commercial Internet Exchange in 1991 with PSINet and AlterNet
- the settlement-free, flat-fee interconnection model the CIX embodied
- Connecting to the Internet, 1993, the early consumer’s guide to getting online
- Aldea Communications and FirstMile.US, carrying connectivity advocacy to the last mile
The innovation worth underlining is institutional. In 1991 there was no commercial precedent for how independent IP networks should exchange traffic: telephony’s answer was settlements, accounting, and bilateral tolls. The CIX founders chose the opposite, a flat membership fee and free exchange of all members’ traffic, betting that simplicity would grow the pie faster than metering could slice it. That bet shaped the Internet’s entire commercial structure. Growth went where friction wasn’t, and the settlement-free model scaled from three networks to the global peering fabric.
It is also worth saying plainly: in an industry whose founding photographs are nearly all men, Estrada built one of the first regional networks, sat as an equal at the table where commercial interconnection was invented, and then wrote the book that walked everyone else through the door.
Publications
- Connecting to the Internet: An O’Reilly Buyer’s Guide, O’Reilly and Associates, 1993
Grokipedia Page
https://grokipedia.com/page/susan_estrada
Wikipedia Page
https://en.wikipedia.org/wiki/Susan_Estrada