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.
Maybe you remember what I said about Group Messaging. That all the RCS deployments would be done faster without this feature. A similar thing we can say about VoLTE Conferencing. Ad-Hoc Multi Party Conference Call (CONF) is one of the basic requirements we have on VoLTE calling. Simply put each VoLTE network has to support conference calling. But to troubleshoot this great functionality can be a nightmare.
Ad-Hoc Multi Party Conference is one of the Supplementary Services supported by Telephony Application Server (TAS) (a dedicated Conference AS is an option too) and it is described in GSMA IR.92, which then refers to 3GPP TS 24.605 and 24.147. Today we’ll take a look at the conference call flow, along with the Mr’ interface between TAS and Media Resource Function (MRF).
Add participant button
Although we talk about conferencing, in fact it’s just a multi-party call. We don’t schedule any conference call for a given list of participants. We can only add additional numbers to an existing call. That’s why we describe the service as an ad-hoc conference. From the mobile operator point of view the conferencing service provides the means for a user to create, manage, terminate, join and leave conferences as well as the ability to update the involved parties. But most of the stuff is truly hidden to the end subscribers.
In general both voice and video conference can be supported, but only the support of audio media is required by VoLTE standard. The maximum number of participants differs network to network, usually it is between 6 and 10. Note, that the functionality is not limited to VoLTE users only, we can add to the call the CS users too.
Our current economy is digitized and generates an exponential growth of person-to-person (P2P) transactions. On the other hand we often face challenges around flexibility, trust, identity and authorization that existing financial instruments are sometimes struggling to address.
And that’s where blockchain comes into play. Blockchain is designed as a secure distributed system with high Byzantine fault tolerance. The most successful use cases for blockchain today are related to financial transactions and the management of financial assets. The most famous examples include Bitcoin, Ethereum, Ripple or Hyperledger.
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.
It’s very interesting (and well, a bit suspicious) that the main focus of most VoLTE textbooks and trainings is signalling. But from the user-point-of-view, it is the voice data, what matters. As an end-subscriber I don’t care about signalling. My only interest is the call quality. But times they are a changin and engineers are asking about how to improve the overall voice-call quality and user experience. Today we’ll go through the basics as jitter, mouth-to-ear delay, packet loss rate or MOS, needed for QoS analysis.
For real-time multimedia we used to have dedicated telephone/radio networks. That has changed and voice/video streams are transported over IPnetwork now.
We should understand that these IP networks were originally designed for data transport. To transport data we prefer the best-effort service model, which allows an easy network scaling and simple routers’ logic. On the other hand we don’t care much if packets arrive in-order or what are the delays between particular packets. We simply wait until we receive a whole file. If any packet is lost, TCP will re-transmit it.
Packets in Data Networks
It’s a different story with the real-time communication services though. RTC applications are less sensitive to packet loss, but they are very sensitive to packet delay. Usage of IP data network as a carrier brings a lot of challenges which have to be addressed by media protocols and network elements.
The last time we discussed 5G and IMS. One of the main drivers for 5G is Machine-2-Machine (M2M) communication. But surely 5G is not the only technology which enables Internet of Things (IoT). Many operators already do support proprietary technologies such as SigFox or LoRaWAN. But there are also 3GPP standardized (Release 13) networks for IoT other than 5G. They are LTE-M and NB-IoT, and they both operate on licensed spectrum. These technologies came a bit later, however now it seems they are gaining momentum.
On GSMA pages you can now find an interactive map with the existing IoT deployments.
Maybe you have already heard about some features as Dynamical Network Slicing, CloudRAN, Network-as-a-Services, … Some basic 5G principals we’ll briefly discussed also in this post. However my question is: What will be the change from the real-time communication point of view? What will be the 5G calling look like? Is the IMS (IP Multimedia Services, don’t confuse with International Microwave Symposium) to stay in the operators’ networks?
5G Deployments Sep, 2019 by 5G Americas
Seems that at the first stage the change will be less dramatic than when we introduced 4G. 4G was in many ways a revolution, whereas 5G is “only” an evolution. In fact 4G and 5G, at least in the beginning, will coexist and complement one each other. Still 5G will have a big impact on our existing technologies and the way we work with telecommunication networks.
I have never planned to talk about such an operator specific matter as KPIs. But since I posted NEWS: Telco Monitoring I’m receiving many questions related to this topic and I guess we can discuss at least the basic principles.
If you have read the VoLTE standards such as GSMA IR.92 or VoLTE Service Description and Implementation Guidelines, you probably noticed that performance monitoring is more or less ignored. And at the same time all operators are asking about it. What KPIs to watch, how, what are the guidelines?
Btw. I always enjoy being in NOC (Network Operation Centre) or war or crisis rooms. Especially during events like NYE. However mostly it is not allowed to take any photos there, so instead I’ve linked some youtube videos showing the scene. Respect to you bros working day and night to keep the network running!
I like statistics. Sometimes it can be misleading or data can be hard to interpret. But it can help us when we struggle to see the forest for the trees.
The last two years the IP-based mobile technologies were booming. If you are working with 4G networks you know it well. This year however the number of new deployments decreased significantly (Sep 2017, source GSMA).
IP Deployments Sep-17
Well, there can be many reasons for that. Rather than guessing, let’s have a fun and take a look on how popular are some telco topics on Google in the last 3 years.