Rate Limit and Traffic Shaping

Support and operation engineers don’t need to understand the majority of algorithms hidden in telecom software. But time to time it helps if you have an understanding of how some particular functionality is implemented.

The typical situation is Traffic Shaping or Overload Protection. Many operators want to understand and test, how their system behaves under a huge load of calls or messages. There are many ways how to implement these features, so let’s take a look at the most common ones.


The easiest way how to protect the system is to define some limit. For example, we can say that our SBC is able to handle only 1.2 mil. parallel calls. If we receive a new invitate which exceeds this threshold, we respond with system error.

Similarly, we can set a limit for CPU or memory consumption. Whenever we reach, let’s say 60 % of the CPU we raise an alarm and don’t allow any new call/registration. As soon as the resource utilization drops below the threshold again, we can resume the standard system behavior and accept new calls.

Sounds reasonable and simple, however, in case that the load is close to our limit – 60 % of CPU – it can lead to so called throttling causing system instability. The last thing which you desire for if you are facing high traffic.

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AR, VR – Real-time communication in 5G

GSMA Intelligence forecasts that the number of 5G connections globally will reach 1.3 billion by 2025, covering 40 percent of the world’s population or approximately 2.7 billion people. At that time, the Americas region is expected to account for over 260 million 5G connections or 20 percent of the global market.

The question everyone is asking in telco last couple of years is – do we really need 5G? Do we really need that throughput for our voice, video and messaging services? Can we significantly improve real-time communication services so that customers would be willing to pay for it? RCS aka Advanced Messaging is a great example of how difficult it can be to find the right business model for new technologies. EVS supported in 4G is more than what we need for voice calling. Although video calling is possible in 4G, not that many customers are using this option on their mobile devices. More popular than video is desktop-sharing, collaboration and communication in context. Well, lower latency and better throughput can be useful – but is it a reason strong enough to invest into the new 5G infrastructure, when collaboration applies mainly to fixed networks?

5G Drivers. Source GSMA

Still there are real-time communication applications which require low latency and huge amount of data so that 4G is not enough. Virtual Reality (VR) applications like 360-degree video will necessitate higher resolutions of 8K and above, and stereoscopic video (which separates left and right eye views in VR) also requires additional bandwidth. When most people hear about 3D video, holograms, Augmented Reality (AR) and Virtual Reality (VR), they mostly think about gaming. And yes, gaming can be a good example and people like to spend money for entertainment. But there are other examples, where AR and VR can make a difference.

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News: Wireshark is 20!

Impossible not to mention. Ethereal – these days known as Wireshark – is twenty! In 1998 Gerald Combs publicly released its first version 0.2.0. And he truly changed the IT (and particulary telco) world. Over the years Wireshark has won several industry awards, and it is one of the top-rated sniffers. Wireshark is a real gift for every engineer who works with a protocol stack. At the same time many BIG companies don’t even realize what contribution Wireshark means to their daily business!




Thank you Gerald and everyone who has helped with this great project!

Comment: Real-time communication & AI

So we have a first robot citizen. When we read about human-robots they are presented as future cleaning-ladies, news anchors, soldiers or sex-machines.

Everyone can imagine possible threats. In the current world of spam and fake news robots can manipulate our reality even in a more advanced way. It’s not just a robot shop assistant which – by the way – mentions how great is a new laundry detergent or your joy-robot asking for an upgrade in a (im)proper time. It can also spy what you have at home, how much time you spend with various activities, assess your income or overhear conversation with your spouse  – all, of course, in your best interest (let’s call it cookies 2.0). Not talking about real malware and ransomware.

In the same way participants in reality show forget about TV cameras, we’ll forget that robots are just robots. They don’t even need to look very real. Our brain is not that difficult to deceive. So the question is how to protect ourselves. At some point AI outsmarts human brain and we’ll need some help.

Let us know in comments section, what is your view and how to protect ourselves – e.g. how a new antispam sw/hw could look like.

SIP URI Overview

Everyone knows that SIP headers like R-URI, To, From, P-Asserted-Identity, Path, Route and others contain Uniform Resource Identifiers (URI) –  sip uri or tel uri. But do you know what formats we can use, with what parameters? As URI is one of the IP communication’s corner stones, it worth to have some better understanding.


Let’s start from the beginning. SIP URI is defined in RFC 3261, TEL URI in RFC 3966 (this RFC defines also modem and fax URL schemes).

SIP URI has a similar form to an email address. It contains typically a username and a hostname, for example test@realtimecommunication.info, where realtimecommunication.info is the domain of a SIP service provider. TEL URI is simply a telephone (landline or mobile) number as tel:+611234567890. It is needed mainly to support CS related scenarios and Mobile Number Portability (MNP). In practice we can see various forms of sip-uris:


Last but not least we have also a SIPS URI, which specifies that the resource is to be contacted securely. For that we use TLS as a transport layer protocol. The format for a SIPS URI is the same, except that the scheme is “sips” instead of sip. Note, that any resource described by a SIP URI can be “upgraded” to a SIPS URI by just changing the scheme, if it is desired to communicate with that resource securely.

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News: RTC in 2017

GSMA has just recently published the final numbers for 2017. As expected the last year we’ve seen less 4G deployments than in 2016.

4G Deployments in 2017

The only exception was the RCS. (Btw. GSMA released its Universal Profile Version 2.0 for Advanced RCS Messaging.)

From the population coverage point of view the last year meant a great step forward. Although many developing countries have been still more focused on 3G (4G coverage is on average 35% there), the overall number of 4G coverage increased significantly.

Population Coverage, © GSMA Intelligence 2017

The main reasons for that are:

  • China has achieved 99% coverage in less than three years and it is now 4G-first
  • In India Reliance Jio has beem driving the technological move towards 4G and other operators are following

Technology Migration© GSMA Intelligence 2017

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Comment: A Piece of Advice for Every (Telco) Company

As a trainer and blogger I have a chance to talk to many engineers from various (telco) companies. And I can hear a lot of similar complains. “We’re just reinventing a wheel, over and over again.”, “I feel like an investigator – to find the right information/documentation is so painful.”, “R&D doesn’t want to share anything.”,  “They are not answering to my questions, they’re just sending a lot of crap to keep me busy.”, etc. The common denominator is that companies don’t encourage engineers to work aloud and share their experience and knowledge. Why? So much effort and talent is wasted.. And by encouraging I mean also that they don’t provide the right tools (no, it’s not sharepoint) and managers don’t lead by their examples.

This can’t be fixed by any process or action points. It is about company/team culture. If managers treat engineers as “resources”, act as if they are more important, or if they say “we’re not at work to make friends” (and some are even so dump to share it on social networks), it is hard to imagine that others would willingly share their know-how. Yes, there can be some lessons-learn filled after project, some reports created – but honestly, what engineers read these documents??

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