Seattle Internet Exchange

The Seattle Internet Exchange (SIX) is a neutral and independent Internet exchange point in Seattle, Washington. It provides shared switching infrastructure through which Internet service providers, content networks, cloud and hosting companies, research networks, transport providers, and other network operators can establish direct peering sessions. By exchanging traffic locally rather than sending it through distant transit providers, participants can reduce latency, improve routing efficiency, increase resilience, and lower dependence on paid upstream connectivity. The exchange is centered on the Westin Building in downtown Seattle and has extended its switching fabric to additional facilities, including KOMO Plaza and Sabey Intergate. It also supports connections through extensions sponsored or supplied by colocation facilities and transport providers. This distributed approach allows networks located in different buildings or regional facilities to participate without requiring every member to install equipment in the primary site. SIX is frequently cited as a model for neutral Internet exchanges because of its independent governance and participant-friendly financial structure. It was originally created as a free exchange point supported by donations. Unlike many commercial interconnection platforms, it has generally operated without recurring participation charges. Its funding has instead been associated with one-time port fees for higher-capacity connections, including 10, 100, and 400 Gbit/s ports, together with voluntary contributions from stakeholders. The organization is structured as a tax-exempt 501(c)(6) nonprofit corporation. The platform supports Ethernet connections at 1, 10, 40, 100, and 400 Gbit/s, depending on the connection location and available service. It supports both IPv4 and IPv6 peering and encourages the use of IPv6 where available. Participants can also use jumbo frames with a maximum transmission unit of 9,000 bytes. The core switching environment is based on Arista Networks equipment, while two route servers run the BIRD Internet routing daemon to facilitate multilateral peering. In addition to its principal Seattle locations, the SIX ecosystem includes extensions associated with facilities and networks such as H5 Data Centers Seattle, Astound Broadband, BSO/IX Reach, Equinix's PAIX SEA, Minnesota VoIP, NOCIX, Reliable Internet's Arrow Calgary service, Wholesail Networks, and Wowrack. These extensions broaden the practical reach of the exchange across regional networks, colocation sites, and transport services. The exchange's significance lies less in consumer-facing branding than in its role as a shared piece of Internet infrastructure and as an influential example of how a neutral, community-oriented peering point can be organized.

The Seattle Internet Exchange emerged as a community-oriented Internet exchange point serving networks in Seattle and the surrounding Pacific Northwest. Its early operating model was notable because the exchange was created as a free peering facility and initially relied on donations rather than recurring charges to participating networks. This structure distinguished SIX from more commercially priced interconnection services and made it a frequently referenced example of neutral and independent exchange governance. The exchange's principal switching environment developed around the Westin Building, a major Seattle telecommunications and colocation location. As participation expanded, the switching fabric was extended to other facilities, including KOMO Plaza and Sabey Intergate. Extensions sponsored by colocation operators and transport providers allowed networks outside the primary building to reach the exchange, creating a broader regional interconnection ecosystem rather than a single-site facility. SIX's operating model combines shared Layer 2 switching with optional route-server participation. Networks may establish bilateral sessions with individual peers or use route servers running the BIRD Internet routing daemon for multilateral exchange. The platform supports both IPv4 and IPv6, and it has promoted IPv6 peering as part of its technical operating model. Jumbo-frame support is also available, subject to the capabilities and configuration of the relevant participants. Over time, the exchange moved from a small community interconnection project to a substantial regional peering platform. Its core equipment has included high-capacity Arista Networks switches, with different models deployed at the Westin Building, KOMO Plaza, and Sabey Intergate. Port options have expanded from lower-capacity Ethernet connections to 10, 40, 100, and 400 Gbit/s services, reflecting the growth of traffic volumes and the needs of large networks. Financially and institutionally, SIX has continued to be associated with a nonprofit, neutral-exchange model. It is organized as a 501(c)(6) tax-exempt corporation. Rather than depending on recurring participant fees, its funding has been described as coming primarily from one-time charges for certain high-capacity ports and voluntary stakeholder contributions. This approach, together with its neutral governance, has made SIX an often-cited reference point for other Internet exchanges seeking to encourage broad participation and local traffic exchange. The present exchange operates as a multi-location interconnection platform in Seattle, with additional reach through facilities and network extensions. Its technical role is to provide a common peering fabric, while its broader infrastructure role is to keep more regional traffic within efficient local or regional paths. The organization remains active, although detailed information about its founders, individual officers, and formal historical milestones is not established in the supplied reference material.

• Creation of a free community exchange

  [1]Seattle Internet Exchangeen.wikipedia.org

  Seattle Internet Exchange was established as a free Internet exchange point supported initially by donations, creating a neutral alternative to recurring-fee interconnection models.

• Expansion beyond the Westin Building

  [1]Seattle Internet Exchangeen.wikipedia.org

  The switching fabric expanded from its central location at the Westin Building to facilities including KOMO Plaza and Sabey Intergate.

• Adoption of high-capacity Ethernet interconnection

  [1]Seattle Internet Exchangeen.wikipedia.org

  SIX developed support for a range of Ethernet port speeds, extending from 1 Gbit/s to 400 Gbit/s as participant requirements increased.

• Development of regional extensions

  [1]Seattle Internet Exchangeen.wikipedia.org

  Colocation facilities, transport providers, and regional networks sponsored extensions that broadened access to the exchange beyond its primary Seattle sites.

A neutral, independent, nonprofit-oriented Internet exchange emphasizing open participation, local traffic exchange, operational resilience, and the absence of recurring participant charges.

• Internet exchange service

  SIX public peering fabric

  The core service is a neutral shared switching fabric that enables participating networks to exchange traffic directly. Participants can form bilateral BGP peering sessions with other members or use the exchange's route servers for multilateral peering. The service is designed to improve local routing efficiency and reduce the need to carry regional traffic through remote transit providers.

• Interconnection ports

  High-capacity Ethernet ports

  SIX provides Ethernet access options at 1, 10, 40, 100, and 400 Gbit/s, subject to the relevant site and connection arrangements. Higher-speed ports are associated with one-time port fees in the exchange's described funding model, rather than routine recurring participant charges.

• Network peering

  IPv4 and IPv6 peering

  The exchange supports peering over both IPv4 and IPv6. IPv6 participation is encouraged, although actual availability depends on the capabilities and configuration of individual peers. This dual-stack model allows networks to exchange routes and traffic across both major Internet protocol environments.

• Routing service

  SIX route servers

  Two route servers running the BIRD Internet routing daemon support multilateral peering. Route servers simplify the operational work required for a participant to exchange routes with many networks while allowing the participant to retain control over its routing policy.

• Remote interconnection access

  SIX extensions

  Extensions connect the exchange to additional colocation facilities, transport networks, and regional providers. Listed examples include H5 Data Centers Seattle, Astound Broadband, BSO/IX Reach, Equinix PAIX SEA, NOCIX, Reliable Internet's Arrow Calgary service, Wholesail Networks, and Wowrack.

• Maintain a neutral nonprofit operating modelStrategy

  Background

  SIX was developed as a neutral and independent exchange intended to maximize participation and local traffic exchange.

  Action taken

  The organization operated as a 501(c)(6) nonprofit and generally avoided recurring charges to participating networks, relying instead on one-time high-capacity port fees and voluntary contributions.

  Aftermath

  The model became one of the most frequently cited examples of community-oriented Internet exchange governance and financing.

  Source

• Extend the exchange across multiple facilitiesStrategy

  Background

  A single-site exchange would limit participation to networks physically present at its main location.

  Action taken

  SIX extended its switching fabric to KOMO Plaza, Sabey Intergate, and other locations through facility and transport-provider extensions.

  Aftermath

  The exchange gained broader regional reach while retaining a common peering environment for networks in different Seattle-area facilities.

  Source

1. 1Seattle Internet Exchangeen.wikipedia.org
2. 2Seattle Internet Exchange official websiteseattleix.net