AS12276 — SFMIX-MGMT

AS12276 announces 1 IPv4 prefixes covering 256 addresses and 4 IPv6 prefixes.

About this network

The management network of the San Francisco Metropolitan Internet Exchange.

What it's used for

• Exchange infrastructure and management. 256 addresses in one /24, four IPv6 announcements, six observed BGP neighbours.

Notable

• The IPv4 block is named for its job: 192.33.255.0/24, netname SFMIX-V4-MANAGEMENT.
• The four IPv6 announcements form a chain out of 2620:11a:b000:: — a /47, then a /48, a /46 and a /45, together covering everything from b000 to b00f apart from 2620:11a:b002::/48.
• Six neighbours. An exchange operator's own network needs to be reachable from the outside, which is a different requirement from the fabric it operates.

Interesting

• The missing /48 in the middle of that chain is the kind of hole an exchange point produces. Peering LAN prefixes are conventionally kept out of the global routing table, so that the fabric is reachable only from the fabric, and the operator announces everything around it.
• What an IXP actually is, in routing terms, is almost nothing: a switch, a room, and an agreement. The addresses here run the portal, the route servers' management side and the monitoring. The traffic that makes the exchange worth existing never appears in this AS at all.

This description is AI-generated, best-effort context — not authoritative, and provided without any guarantee of accuracy.

Announced prefixes

• 192.33.255.0/24
• 2620:11a:b000::/47
• 2620:11a:b003::/48
• 2620:11a:b004::/46
• 2620:11a:b008::/45

Upstream networks

• AS6939 Hurricane Electric LLC
• AS1299 Arelion Sweden AB
• AS36086 Telx

Adjacent networks

• AS6939 Hurricane Electric LLC
• AS1299 Arelion Sweden AB
• AS36086 Telx

Internet exchanges

• San Francisco Metropolitan Internet Exchange — San Francisco, United States