Intelligent Solutions


Simon Woodhead

Simon Woodhead

23rd December 2020

By Simon Woodhead

You’re hopefully aware that STIR/SHAKEN is coming in the USA and where we stand with it. See “we’re 1%ers” if not. You’ll have also seen our previous update explaining what we were doing with incoming calls – see “STIR/SHAKEN – things you need to know and do” if not.

Today we have a new update: outbound signing of calls is live.

Any call passed through Simwood which is heading to the North America Numbering Plan Administrator (NANPA) areas will be attested by Simwood to assist in the ITGs valuable work on traceback.

Uniquely to Simwood, this includes calls originating anywhere else in the world rather than simply NANPA-to-NANPA. So a call from a UK number to a US number will be signed by Simwood, with an appropriate level of attestation. This feels the right thing to do given the spirit of the regulations as much as their letter.

The only scenario where we won’t add an attestation is direct wholesale customers of Simwood Inc, who will be bona-fide carriers signing themselves. In this scenario we transparently transit their attestation.

We will not be signing calls to any part of the world outside NANPA but can do if ever required. We’d encourage our UK colleagues at Ofcom to consider the adoption of the requirement (not simply part of it) and are very willing to share our experience.

In the previous post we described the three levels of attestation, that could be applied but not our logic for doing so. This will be:

AFull AttestationThe end-user is known to Simwood. Given we are predominantly wholesale we determine this to be the presence of Emergency Calling data, EHA/999 or E911, for numbers which are on-net. This also includes direct customers.
BPartial AttestationThis is calls from numbers which are on-net but we do not know the customer, i.e. there is no EHA/999 or E911 data. This also includes third party (off-net) numbers for direct customers.
CGateway AttestationThis is wholesale traffic from known wholesale customers but from off-net numbers.

As can be seen it is perfectly possible for all Simwood customers to obtain the coveted A-attestation. To get it numbers need to be on-net, i.e. allocated by or ported to Simwood, and you need to have populated emergency calling data. The exception is direct customers, such as our enterprise customers, who are known to us directly without the necessity for emergency calling data.

We’d remind customers that we’re not yet filtering incoming calls as very very few are signed, but we will when there is a critical mass. So will others and we strongly suspect that some providers will screen C attestations and unattested calls, whilst end-users may screen B attestations based on an ‘unknown caller’ or ‘spam call’ type warning on their mobile device.

We think this will thin the herd of resellers pretending to be carriers as customers seek A attestation which very few can provide. The time is therefore now to port your numbers to Simwood and let us take care of it.

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