Signalling Storms and QoS: 2 hazards to control through 5G

When we talk about Internet of Things most of times we are thinking in mobility. Although this is not necessary in many architectures, when we talk about some of the IoT markets like Fleet control, Connected Car, Trackers, Wearables and so on, mobility in the solution is a must.

There are different technologies to provide wireless connectivity for the IoT Market in vast areas, as LoRA or Sigfox… but because coverage, capex, inversion and operative costs Mobile Networks already rule the market and probably it continues ruling in the short future.

In fact, in order to provide IoT connectivity, what Telco operators are doing is reusing and offering their conventional 3G and 4G networks. This avoids inversion and provide connectivity to the new wave of sensors and devices which populate the Internet of Things. However this is also link to a couple of issues which are added to the perhaps the mostly known about the battery necessities of the IoT devices:

– Signalling storms
– Quality of Service and/or Service Level Agreement

But, why is this an issue for a conventional mobile network? Why does this not affect to the conventional users in the same way?

First of all an IoT device has not a standarization. A mobile handset typically used by a person has a quality control which must be accomplished during its manufacturing. Sometimes it also fails and a signalling storm is created collapsing a mobile network through this kind of DDoS (it happened with an iPhone version in some networks). But, what is a signalling storm?

A signalling storm happens when lots of devices try to connect to a network, at more or less the same time. That generates a kind of DDoS attack which can collapse or affect an entire network through a problem in one of its core elements.

If thousand of IoT devices are not properly configured to avoid this (and many times it doesn’t depend of the telco) a massive simultaneous reconnection can affect in this way.

Further more, because network avaibility and global service necessities in many IoT cases of use there are roaming scenarios when a SIM Card of an operator are using the mobile network of other.

In this last case Quality of Service (QoS) and Service Level Agreements (SLA)are also a frequent gap. When the mobile networks were designed IoT was only an idea and it was not considered.

So traffic it not quality considered at End to End level. For sample: in a roaming scenario there is not difference at network level between an user who is not able to connect with Google and a telehealth device. This is an important gap.

Additionally, between operators there are not agreed quality times to resolve an incident because, in many cases, this only affects to entertaiment traffic and not industrial or critical one (except in the case of massive incidents). This is not compatible with a Connected Car solution or an International Fleet Management.

Yes, standard 4G-LTE specifies a QoS configured at APN level, but it doesn’t affect to the signalling or to the network capacity. Only to the PGW discarting policy and it not clear than in a global scenario it is going to be alligned between all the involved actors.

And here it is where standard 5G appears. Everybody knows about 5G mainly because the real time applications and low latency flows. Also de high throughputs. Everything about that is very well but the really good point of the 5G standard is try to fix the described issues. How? Response is multislicing.

Multislicing is going to be a new technology, a paradigm, which is going to permit slice the network for a kind of service. This means: book network resources to assurance the traffic quality and control at end to end of the service. Based in Cloud/Virtualization/SDN technology in case of a Signalling Storm network will be able to resize itself in order to support the avalanch. Cisco is already working in some interesting proposals in this way.

Also this would affect to all the communication chain guaranting times between nodes and avoiding possible bottlenecks in some of them.

What is not clear at this moment is how this is going to affect to a roaming scenario and how this slicing information is going to be communicated between telco operators. In this way if a Connected Car with a SIM card goes to other country through Europe how the visited network is going to know the slicing necessity and share it with the home network which owns the SIM is an issue now. It is being discussed at 3GPP level.

New vSIM technologies can help also with this, but it is not clear the prevision and if it will be valid for every operator accross the world.

Conclussion here is that yes, 5G provides an increament of the speed, a decreament of the latency and its going to permit marvellous applications. But the main point in my opinion it is going to be the first network designed 100% for Internet of Things.

Juan de la Cruz
@jdelacruz_IoT

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