The Seattle Internet Exchange (SIX) was originally established in April 1997 as a private interconnection between two ISP's in Seattle's Westin building, whose traffic was traveling from Seattle to Texas and back just to cross from one side of the floor to the other. Starting in June 1997 other ISP's became interested in interconnecting, and the SIX became active June 20th, 1997. Networks began to participate in the SIX due to the low/no cost involved, and it began to grow.

Faced with a growing number of participants and a rather ad hoc arrangement of hubs/switches and cable termination points, early members of the exchange petitioned the building for a neutral space. The building management obliged and allocated space for the SIX adjacent to the building's T1/T3 (and later fiber) meet-me rooms. This provided the SIX with a neutral, provider independent home.

The SIX welcomes contributions.

The SIX offers 1GbE, 10GbE, 40GbE, 100GbE, and 400GbE port options. One-time port fees are detailed on our join page. The SIX does not charge recurring fees, but they are offered as a payment option.

There are no requirements of participants, other than they follow the rules of the exchange. There are no peering requirements, although peering with other members is encouraged and is basically the point of connecting to the exchange. We offer optional route servers.

For information about joining the SIX, click here.

Port counts over time can be found here: csv png xls

Information on other exchange points can be found here.

Euro-IX videos about IXPs and peering:

NANOG 70 presentation (PDF) by Jared Reimer for the 20th anniversary of the SIX:

Major Milestones:

  • 1997-04: IXA and Wolfe form private interconnect.
  • 1997-06: Hub added and Altopia connects. The exchange is born.
  • 1997-11: Renumbered into Bill Manning's EP.NET IP address space.
  • 1998-01: Petition letter given to Westin Building management requesting neutral space.
  • 1998-05: First "national" network, AboveNet, joined the exchange.
  • 1998-06: Replaced 10 megabit hub with a Cisco 1900 XL 10/100 switch.
  • 1998-07: Moved out of IXA suite and into the current SIX space.
  • 1999-02: Microsoft joined the SIX which acted as a considerable catalyst for growth.
  • 2001-05: Incorporated as a non-profit.
  • 2001-09: Cisco 4912G installed. First 1GbE ports became available.
  • 2001-12: PAIX / SIX interconnect turned up.
  • 2006-09: First 10GbE participant.
  • 2007-05: Cisco 6509 installed as the core switch.
  • 2008-09: Received IRS section 501(c)(6) income tax exempt status.
  • 2009-02: Activated VLAN specifically for multicast peering.
  • 2009-07: Cisco Nexus 5020 installed for 10GbE participants.
  • 2009-07: Renumbered into IP address space assigned by ARIN.
  • 2009-07: 10GbE port fee lowered from $10k to $5k NRC (Non-Recurring Charge).
  • 2011-08: Arista 7508 installed for 10GbE participants.
  • 2011-09: Cisco Nexus 5020 retired.
  • 2012-08: KOMO Plaza (Fisher) switch upgraded from Cisco 4912G to Extreme X670 and ISL increased from 1 Gbps to 10 Gbps.
  • 2013-04: Began using AMS-IX's "arpsponge" software. Much appreciation to Steven Bakker, Arien Vijn and AMS-IX for sharing this brilliant technology.
  • 2014-02: First MTU 9000 peering.
  • 2014-07: Route servers introduced.
  • 2014-08: 100GbE and 40GbE beta testing offered.
  • 2014-09: 100GbE and 40GbE port fees introduced at $16k and $8k NRC respectively, plus optic.
  • 2014-11: Westin: Arista 7508 upgraded to 7508E.
  • 2014-11: Sabey Intergate: Cisco Nexus 3524P switch activated with 20 Gbps ISL to Westin Arista 7508E.
  • 2015-01: 10GbE port fee lowered from $5k to $3k NRC.
  • 2015-01: First 100GbE participant.
  • 2016-10: Westin: Cisco 6509 retired.
  • 2016-11: Blackhole support implemented.
  • 2016-12: Westin: Arista 7512R installed for 1/10/40/100GbE participants.
  • 2017-01: 10GbE port fee lowered from $3k to $2k NRC. 100GbE and 40GbE port fees changed from $16k and $8k NRC respectively, to $10k NRC with optic now included.
  • 2017-08: KOMO Plaza: Extreme X670 replaced with an Arista 7280SR-48C6 and ISL increased from 10 Gbps to 300 Gbps.
  • 2018-03: Sabey Intergate: Cisco Nexus 3524P replaced with an Arista 7280SR-48C6 and ISL increased from 20 Gbps to 300 Gbps.
  • 2018-10: Westin: Arista 7508E upgraded to 7508R.
  • 2020-01: 10GbE port fee lowered from $2k to $1.5k NRC. 100GbE and 40GbE port fees lowered from $10k to $7.5k NRC.
  • 2022-03: Westin: Arista 7808R3 installed for 400GbE participants.
  • 2022-04: KOMO Plaza: Arista 7504R3 installed for 1/10/40/100/400GbE participants.
  • 2022-04: 400GbE port fee introduced at $15k NRC.
  • 2022-05: First 400GbE participant.
  • 2022-11: KOMO Plaza: Arista 7280SR-48C6 replaced with an Arista 7504R3 and ISL increased from 300 Gbps to 800 Gbps.
  • 2024-02: Sabey Intergate: Arista 7280SR-48C6 replaced with an Arista 7504R.

Member Count:

Year Count
1997 4
1998 16
1999 24
2000 31
2001 39
2002 38
2003 60
2004 67
2005 79
2006 82
2007 98
2008 115
2009 132
2010 140
2011 151
2012 156
2013 170
2014 189
2015 206
2016 236
2017 284
2018 290
2019 314
2020 340
2021 342
2022 355
2023 365
Member Count

Aggregate Peak Traffic Milestones:

Month Gbps
2007-07 10
2008-06 20
2009-01 30
2009-07 40
2010-02 50
2010-09 60
2010-12 70
2011-03 80
2011-06 90
2011-09 100
2012-03 110
2012-09 120
2012-10 130
2012-11 150
2013-02 170
2013-09 190
2013-10 220
2014-01 240
2014-02 250
2014-03 260
2014-06 270
2014-09 290
2014-11 310
2014-12 320
2015-02 360
2015-05 370
2015-07 380
2015-08 410
2015-09 430
2015-10 490
2015-11 500
2016-01 520
2016-02 550
2016-04 560
2016-09 590
2016-10 620
2016-12 640
2017-01 650
2017-02 700
2017-04 710
2017-05 760
2017-06 850
2017-07 860
2017-08 880
2017-09 960
2017-10 980
2017-11 1,030
2018-11 1,060
2018-12 1,100
2019-01 1,120
2019-05 1,130
2019-08 1,150
2019-09 1,200
2019-10 1,350
2019-11 1,370
2019-12 1,420
2020-03 1,570
2020-04 1,630
2020-05 1,680
2020-11 1,850
2021-02 1,980
2021-04 2,030
2021-12 2,080
2022-01 2,270
2022-08 2,290
2022-09 2,460
2022-10 2,500
2022-11 2,570
2022-12 2,590
2023-01 2,780
2023-03 2,830
2023-08 2,860
2023-09 3,120
2023-10 3,140
2024-08 3,370