News: Finally 4G?

IMS was designed in a very a general way. As a service network which is access independent, supports multiple identities and it is very expensive to implement. Sometimes less is more – at least in the beginning. That’s also why we have the VoLTE – a minimum IMS profile which reduces the scope into something manageable and more practical.

As the VoLTE has been around for a couple of years already and works fine, the early adopters are looking for more – HD Voice, EVS, WebRTC and other technologies. Recently T-Mobile USA (DIGITS) and AT&T (NumberSync) announced their solutions for multi-device feature. Not all the features are always successful or truly practical – but this time I’d think more operators will follow. Btw. with IoT to come I wonder when exactly we will see a first virtual entity (agent) seamlessly moving from one devices to another 🙂

News: Telco Monitoring

I always enjoy to visit telcos’ monitoring centres. One feels like to be in NASA. It’s a pity that mostly it is not allowed to take any pictures.

AT&T Monitoring
AT&T Monitoring

It is interesting that rarely there is just one vendor of this monitoring. Usually it is a mix of various applications, which inform about the most important KPIs and events. Often we can see open applications to be used. If you are working in support you probably know at least some of them – cacti, zabbix, nagios, observiumMRTG, munin, zenoss, etc. One of them is grafana.

Grafana
Grafana

I’ve recently seen a T1-operator monitoring based on Grafana. The nice thing about it is that it allows to include various data sources, analytics where we can easily combine charts with related events and it supports multi-tenancy. Just before Christmas we have got a new version 4.1 with a new alerting feature. The alert rules are easy to configure using existing graph panels and threshold levels can be set simply by dragging handles. The rules will continually be evaluated by grafana-server and notifications will be sent out when the rule conditions are met. Besides the altering there are many other improvements and enhancements.

Anyway whatever tool you use, happy NYE monitoring!

Challenges of Automated Testing (for telcos)

Recently I have been asked for an advice regarding automated testing. I spent several years in R&D designing our test framework (for SMSC, MMSC, RCS, IPSMGW, ..), sometimes I felt like trying to break a wall, sometimes it was very rewarding (at least for me it is rewarding to find a bug 🙂 ). There are some lessons learnt I’ll remember for a long time. I’m afraid this post won’t be a short reading.

Fukushima Nuclear Power Plant

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News: UAVs and LTE

Drones, 3D printers and Mobile Internet are associated with the latest technology development. For a long time computers were providing us only with virtual values. They allowed us to learn, entertain, communicate, but they hardly ever created anything what we could really touch. That is about to change. It will take some time for sure, there will be a lot of disappointment, but at the end of the day I’m quite sure IoT, Drones and 3D printers will have even a bigger impact on our lives than the mobile phones have now.

Amazon Prime Air
Amazon Prime Air

You probably remember the first news about the Amazon Delivery using Drones/Unmanned Aerial Vehicle (UAV) back in 2013. Since then this industry has skyrocketed. Sure that brings also some challenges. An interesting fact is, that LTE can help to overcome some of them.

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News: Internet in Vivo

Do you remember IT 20 years ago? AltaVista, Win95, Linux 2.0, … and Deep Space Nine 🙂 Things have changed a lot. In 90s I was interested in Artificial Neural Networks and Artificial Life. Nothing could be farther from the real life that time. But our technology is developing very fast. So it is genetic engineering and biology. Our scientist are now able to create a real artificial cell. Or at least they have JCVI-syn3.0 – a working approximation of a minimal cellular genome, a compromise between small genome size and a workable growth rate for an experimental organism.

Deep Space Nine

I can imagine that after some time we’ll be able to monitor and analyze the behavior of our cells in the same way as we’re monitoring the computer networks these days or as we want to do it with IoT. I doubt we’ll use SNMP, but surely some intelligent cells could trigger an alarm once they’ll register low sugar level or they’ll notice reduced activity of dopamine-secreting cells.

The research takes long and it is hard to predict the results. But our smart phones are not that far from tricoders in the DS9, are they? Looking at what the mankind was able to achieve within just one generation why not to be optimists? A better technology doesn’t mean better life anyway.

News: Li-Fi – pushing the IoT forward

Do you switch-off  your smartphone or wifi, when you go to sleep? Many people do. I’m not going to discuss if the waves have any real effect on our health or psyche. But undoubtedly in the industry with more and more active devices we have to think about possible interference. Especially in the electromagnetic sensitive areas such as in aircrafts, hospitals or chemical plants.

Fortunately there is a new technology which doesn’t utilize the radio waves but still belongs to the same standard family 802.11 as Wi-Fi. Li-Fi is a bidirectional, high speed and fully wireless communication technology, that uses light from light-emitting diodes (LEDs) as a medium. The visible light spectrum is 10,000 times larger than the entire radio frequency spectrum. On the other hand the light waves cannot penetrate walls which makes a much shorter range. Still the direct line of sight isn’t a must. A light reflected off the walls can achieve 70 Mbit/s!

So what is the real data rate? The Estonian Velmenni startup  just announced that they are able to send data at up to 1GBps. That means 100-times faster than via Wi-Fi. As the British scientists have even reached the data rates of over 10 Gbit/s, which is more than 250 times faster than current broadband, we can expect further improvements in the future.

 

Headers in User-centric networks

One of the key reasons why we need the IMS is the support of multiple devices for the same public identity. Simply put we don’t care what physical device our counterpart has, we just call and it is up to the network to select the particular device or more devices. For example my buddy can be connected via 3G or 4G and wifi from his smartphone, and he can be also connected from a web browser using the WebRTC (and well there are already some operators testing this).

As the logic says the key headers which are being used for routing will remain the same.

The examples here are taken from real networks (AS/CSCF). The exact ids and IPs were modified. You can enjoy the diversity of headers we can find all around the world. There could be much more of them, but I don’t want to have the post too long and boring.

 

Request-URI
INVITE sip:0123456789;
phone-context=ims.mnc000.mcc000.3gppnetwork.org@ims.mnc000.mcc000.3gppnetwork.org;
user=phone SIP/2.0

or

INVITE sip:+12345678912@ims.operator.com;
user=phone SIP/2.0

or just

INVITE sip:12345678912@server.networks.operator.com SIP/2.0

 

P-Prefered-Identity
P-Preferred-Identity: sip:+12345678912@ims.operator.com

P-Asserted-Identity
P-Asserted-Identity: sip:+12345678912@ims.operator.com
P-Served-User
P-Served-User: <sip:+12345678912@ims.operator.com>;
sescase=orig;regstate=reg

 

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Crack the NAT

It is really hard to predict the future. The authors of SIP and SDP designed (1996) a great concept which really addressed the needs of not just real-time communication for the next two decades. But they also believed the the Network Address Translation (NAT) is only a temporary solution which will be obsolete once everyone will use IPv6. In 2015 we still use the NATs and I’d think (! the same mistake again) that we’ll use it for a couple more years.

NAT is technique  which became in conjunction with IP masquerading a popular as an essential tool in conserving global address space allocations in face of IPv4 address exhaustion. These days the NAT is used also for security reasons e.g. topology hiding, port and IP restrictions etc.

The basic functionality of NAT is to translate one IP into another. Typically we can found NATs which mask behind one public IP a whole private network (one-to-many NAT). The traffic then can originate only from the private network (private IP space is not directly addressable from the public network).

Why we care about the NAT anyway? And what’s wrong with the SIP?

Right. Let’s remind that the SIP+SDP are used to establish a media session. It means we’re exchanging IP addresses of the originator and recipient which will be then used for (e.g. RTP, MSRP) data stream. These IP addresses are in the SIP body in the SDP content.

SDP with IP behind NAT
SDP with IP behind NAT

The media communication is then established on these IP:ports. As the addresses and ports are private the other clients can’t use them as they don’t see each other.

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Someone’s Watching

The quantum physics says that some events will happen differently if someone is watching. And one doesn’t need to be a physics to have that experience. At least my performance is always worst when someone is watching me playing piano.

Authors of IMS Presence System were either aware of it or they knew that there can be a thin line between being a watcher and being a stalker. Either way IMS allows to inform a presentity about watchers and authorize their subscription.

The key specification is the RFC 3857 which defines so called watcher info (winfo) event “template-package”. Event template-packages are event packages that can be applied to any other event package (so not only presence). The winfo provides the users with information about who is watching the subscribed resource. If the winfo is applied to presence (see previous posts Presence – More than you wanted to know and Is the Presence Social?) the value of the Event header field is set to presence.winfo.

Event: presence.winfo

The package defines a new MIME type application/watcherinfo+xml. When a SIP request or response contains a Content-Type header field set to application/watcherinfo+xml, it is indicating that the body is an XML document that contains watcher information.

NOTIFY sip:Richard@operator.com SIP/2.0
Content-Type: application/watcherinfo+xml
<?xml version="1.0"?>
   <watcherinfo xmlns="urn:ietf:params:xml:ns:watcherinfo"
                version="0" state="full">
      <watcher-list resource="sip:Richard@operator.com"
                    package="presence">
        <watcher id="23456abcd" event="subscribe"
                 status="pending">sip:Jorgen@operator.com</watcher>
      </watcher-list>
   </watcherinfo>

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