ALL IP by the short hairs-Part 1

all-ipIf we were to summarize the current situation in the ALL IP market, we would see that the migration from ISDN to ALL IP has reached a stage where the number of IP-based telephone connections has exceeded other fixed-line connections such as analog or ISDN. In contrast to other VoIP/SIP providers, Germany’s largest carrier has not been able to offer SIP trunk connections in the last year, thus many business customers could not migrate from ISDN point-to-point connections to ALL IP.  Another important point to mention is that the offer of cloud-based ICT solutions has increased therefore migration to ALL IP is even possible for non-office environments.


Michael Bindner:

ALL-IP Migration and Special Services

all ip migrationSpecial services are offered via analog or ISDN connections in combination with terminal devices by service providers.

The particular challenge is now to guarantee the customer all these special services despite the on-going migration to ALL-IP. For the customer, the question is: will it work and who is responsible for it?

First of all, let us have a closer look at these special services. Deutsche Telekom lists the following services:

  • ·         Alarm systems
  • ·         Electronic cash terminals
  • ·         Elevator emergency call systems
  • ·         Accounting systems for medical doctors/physicians
  • ·         Remote meter reading systems
  • ·         Medical alarms
  • ·         Pay phones

Especially alarm systems are very common, taking into account the fact that alarms such as fire, burglary, heating, cooling or power failure, pump defects, door monitoring, water-pipe-rupture and many other functions are supervised and, in case of an emergency, are reported as soon as possible to mobile phones, fire departments, the police or security companies. Broadly speaking, services related to these problems have to be alerted – reliably and quickly!

Special services include also applications such as ISDN Eurofile transfer, fax, PBX maintenance which are integrated in company processes.

Many providers do not consider this as a problem because in most cases IP-based solutions are currently available. One of the most common examples is the electronic cash terminal. dataphone

Analog or ISDN point of sale devices can be exchanged at a reasonable price by now. Some providers offer this service even for free. Nevertheless, particularly in financial transactions, the device function requires maximum reliability.

In case the customer uses applications which do not yet have an IP solution or which are too expensive to migrate to IP, the whole subject has a greater impact. Investment protection plays an important role.

technology of All-IP

Technology of All-IP

Therefore, let us have a closer look into the technology All-IP. All these aspects above need to be considered in each case individually.

Voice and Voice Applications

Almost perfect migration solutions for voice and voice applications have been created thanks to decades of very intensive development. The quality is far higher compared to ISDN and analog solutions. HD voice or voice in Hi-Fi quality can be achieved. Basis for this is the fact that humans perceive speech in a different way than machines. A short example without getting too much into the technology below:

In case voice packets are lost, clicks and drop outs are normally expected. Cutting-edge technology compensates this problem by stretching the packets and adapting the transition from one to the next packet according to the sound. How does this affect the listener? The listener does not notice it because the voice sounds only slightly deeper and no noise occurs.

Why do I mention this? This example mentioned above is an important aspect when migrating from conventional technology to ALL-IP and integrating the new technology.

ISDN PBX maintenance

Why is this an important example? Large ISDN PBX systems which are operated by the manufacturer are often quite expensive and are deeply integrated into internal corporate processes. IP upgrades are rather complex and cost-intensive if at all possible. A special feature of ISDN is the synchronous connection which does not accept package loss, however the network is very stable but rather slow. Error corrections have been left out since they were not necessary.

PBX maintenance bear the risk that only one single transmission error can near-irretrievably put the PBX out of operation.

Is there a solution for this?

Yes, there are solutions but not all will be supported by every provider and terminal. It is the customer’s responsibility to clarify this.

Deutsche Telekom’s official statement mentions that functionality of a special service operating via an ALL-IP connection can only be guaranteed by a qualification test of the service provider. Therefore, it is important that you as the customer contact your service provider to agree about further steps before actually migrating to IP.

What does this mean from the technical point of view?

A brief excursion into the technical details of ISDN, tells us that, it is a technology which even differentiates between voice and data. In case of EuroFile transfer or PBX maintenance connection, a request for comment will be created, more precisely RFC4040, payload format for a 64 kbit/s transparent call. This is a quasi standard for processing this kind of data. Thus, in case you have a media gateway or a PBX and your provider supports RFC4040, you are well prepared to successfully migrate your special service to IP.


RFC 4040 in combination with a sufficient bandwidth and Quality of service (QoS) enables a secure and error-free deployment of ISDN data transfer via the ALL-IP network.

From the technical point of view, analog data connections via analog and ISDN connections cause problems. Here, the customer along with the provider has to prove each case separately. Nevertheless, functional reliability cannot be guaranteed and can be affected by any kind of change in the provider’s network.

In general, experiences with many customers as well as tests show that data transmission rates up to 33 kBaud have a good chance of a successful migration into the world of ALL-IP.

Randolf Mayr:

Long live ALL IP

all ipIt is no new that ISDN will soon be switched off. Up to what point the whole procedure is planned to be done is also well known. There will be no or almost no delay because the necessity on the part of the carriers is clearly articulated and mandatory. Companies are forced to take action sooner rather than later. Two possible solutions are available for the conversion to ALL IP.

It is time for a “new” network

Technically speaking, ISDN stands for Integrated Services Digital Network, from the user’s point of view, a long-standing, stable, and reliable communication network which standardizes a digital telecommunications network and unifies various services such as telephony, data, teletext or datex-P on one single network. Previously, each service required its own network and all networks were connected via gateways.

The term ALL IP means unifying and converting all currently existing transmission technologies in telecommunications networks on the basis of Internet Protocol (IP). Thus, services such as telephony, television and mobile communications will be provided by means of a uniform network protocol and no longer via the classical circuit switching. The switch to IP-based lines significantly reduces the complexity of networks while the number of operating network components decreases.

Migration process

The migration from ISDN to ALL IP initially affects private and small business customer’s point-to-multipoint connections. Business customer’s that frequently used point-to-point connections (buzzword: SIP trunk) are expected to be switched off  by Deutsche Telekom at around the time of CeBIT 2016 and alternative carriers are even one step ahead.

From the end of 2015 Deutsche Telekom offers its business partners up to eight parallel voice channels. Due to regulations, customers with more than ten phone numbers per basic ISDN connection currently have to apply for a second ALL IP connection in order to keep their phone numbers. Hence, it makes sense to actively develop an approach already in the run-up phase or to consider changing to another provider.

When evaluating which decision to take, one should consider how old the current operating PBX is, whether it is worth purchasing a new one, or whether the PBX has only been operating for a few years and it already supports VoIP. In the end a simple, economic cost-benefit analysis needs to be undertaken and an evaluation made.

Two options are available for the switch from ISDN to ALL IP

One solution is the migration of the already existing ISDN infrastructure by means of an ALL IP media gateway and the alternative is the replacement of the PBX by an ALL IP communication solution for both voice and data which can be integrated into the network infrastructure.

Teldat with its very long tradition in the telecommunication and IT market, provides both approaches: migration as well as the integration of an ALL IP communication solution. In our next blog entry we will look further into the available solutions for both approaches.

Bernd Buettner:


toipWe live in a digital world. Entertainment, work, information, social relations… today everything is digital. The benefits are obvious. Digital information is much easier to store, transfer and handle than analog and is more powerful.  If we think about it we can find many fields where digitalization has had a remarkable impact. In this article, however, we will only consider the impact on telephone networks.

Regardless of whether the telephone was invented by Alexander Graham Bell or Antonio Meucci (or…), it is clear that it started out as analog, and it remained so for many years. Logically, improvements were made over the years but being inherently analog in operation until the mid-60s, deficiencies in the quality of transmitted voice were inevitable. This was especially the case over long distances that required signal regeneration at intermediate stages, leading to information loss and the introduction of noise. The digitalization of the telephone network was a breakthrough in this regard, since the digital signal is transmitted unchanged regardless of the distance and of the intermediate stages required between sender and receiver.

Integrated Services Digital Network (ISDN)

While the move to a digital network paved the way for its use with a range of other services in addition to voice, the final leg, the last mile, also needed to be digital. This step took place many years later with Integrated Services Digital Network, ISDN. As the name suggests, ISDN allows different services to be used over the telephone network on a single line, digital of course.

The advantages of ISDN are clear: firstly, the sound quality (which is why even today they are still widely used by the radio industry), secondly, the extra features (rapid call setup, support for multiple terminals on the same line or direct inward dialing and caller ID), and thirdly, the additional services such as data or video transmission.

ISDN was introduced by CCITT (ITU-T) in 1988 and had its golden moment during the 90s, being deployed with varying success in countries around the world such as Japan, Australia, India and the United States. The biggest impact was in Europe, however, in countries like Norway, Denmark, Switzerland and above all Germany, which had 25 million channels (29% penetration) and one in five lines installed worldwide.

In the late 90s and early twenty-first century two events mark the decline of ISDN; on the one hand, ISDN cannot keep up with market demands for greater speed, and on the other, the cost of Digital Signal Processors (DSP), which allow more advanced line modulations, lowers significantly. It is the beginning of ADSL and the decline of ISDN.

ISDN, the new paradigm in communications

During the first decade of the twenty-first century, ISDN gradually loses ground to ADSL and from 2010 all ISDN service carriers gradually announce its withdrawal. In 2010, for example, NTT announces its intention to migrate all ISDN phone lines in Japan to IP technologies, in 2013 Verizon decides not to install anymore ISDN lines in the USA and in 2015 BT announces its intention to discontinue the network in the UK. Curiously, however, Deutsche Telekom (DT) in Germany adopts the most aggressive stance. By far the world’s largest ISDN provider, it has already begun migration to ADSL/IP technologies having set an aggressive horizon of 2018 for cutting off ISDN completely.

All carriers with active ISDN networks will no doubt be following the transition of the German DT network very closely and it will likely mark the way forward. DT’s commitment is to network modernization and improving customer service while minimizing the impact on the customer. The proposal, therefore, is to offer data services and voice over IP on the same telephone line (ADSL/VDSL) but at the same time giving the customer the opportunity to keep their existing ISDN infrastructure, emulating the ISDN lines from the EDC to their current ISDN PBX.

The use of xDSL and IP services allowing the customer to maintain their internal ISDN infrastructure practically eliminates any impact on the customer, who controls the evolution of the network to an integrated and up-to-date service.

This is an ambitious project and key for Deutsche Telekom. For this reason, following a rigorous selection process, the company has forged close relationships with partners who have proven ability in providing the solvency, experience and agility needed. Within this framework, Teldat has been entrusted by Deutsche Telekom with the task of supplying the access devices.

Marcel Gil: SD-WAN Business Line Manager