CLI manipulation – Just Say No!


By Peter Farmer

Those of us of a certain age will remember the “Just Say No!” campaign in relation to the war on drugs. Fast forward from Nancy Reagan to UK telecoms in 2021 and there’s another seductive moral hazard knocking on the door – network number manipulation.

With surcharges for malformed CLI in signalling, or for terminating some calls originated by networks that themselves have high termination rates, measurable in pounds per minute, some providers may be tempted to overwrite elements of the signalling to avoid incurring the high costs of conveying these calls.

Some changing of elements of the signalling, such as asserting an +448979 for invalid CLI at the international gateway, are embedded in the Ofcom rulebook as acceptable. Scrotitude, such as overwriting a Congolese network number, with a UK network number to avoid a surcharge (and by extension either aggregating traffic on a ‘cheap route’, or pocketing a surcharge passed on) is not cool.

We have heard murmurings in the industry, suggestions from otherwise credible operators that ‘calls with a UK network number won’t be surcharged’ which are one step away from encouraging the behaviour we mentioned.

The rules on these matters are clear; NICC ND1016 is embodied in General Condition C6, and regard for various other standards, such as the ITU’s suite of recommendations, is in General Condition A2. We have blogged extensively on the subject too.

We understand there will be those out there who think network number manipulation is a victimless crime – but consider this – multinational networks like Vodafone and BT have footprint in various countries – ironically, they are likely to be, in some cases, surcharging themselves for the high termination rates they charge in their foreign affiliates. But this global presence gives them the ability to route some traffic off-net and compare the originating and terminating CDRs.

If I were in Vodafone, I’d do just this, and then (assuming I found just cause) raise a very large, retrospective bill while filing all manner of complaints to Ofcom about the CLI manipulation.

So, if you’re thinking about engaging in CLI scrotitude, take a leaf out of the former First Lady’s playbook – Just Say No!.