AS6686 ATT-GCH-VOI-SF-AS VoIP platform - ex Concert

ATT-GCH-VOI-SF-AS is one of a pair of small AT&T Global Network Services

autonomous systems carrying a VoIP platform, this one anchored in San

Francisco. The registrant is AT&T Global Network Services Nederland B.V., the

Dutch entity through which AT&T holds much of this legacy RIPE space.

What it's used for

• A single /24 of infrastructure address space for a voice-over-IP platform — not customer or subscriber addressing.
• Its sibling AS, [AS6688](https://asn.ipinfo.app/AS6688), carries the equivalent Los Angeles platform on the adjacent /24.

Notable

• The RIPE description records the platform as ex-Concert. Concert was the global joint venture between AT&T and BT, announced in 1998 and unwound in 2002; the network assets were divided between the two parents, and AT&T's share still shows up in registry data under handles like this one.
• This is a carrier platform AS, not an eyeball or transit network. Its address footprint is tiny by design — a service platform needs a handful of addresses, not a subscriber pool.

Interesting

• The pairing of two nearly identical ASNs (6686 / 6688) with two adjacent /24s on two US coasts is a classic redundancy layout: the same service, deliberately split so that neither site is a single point of failure.