Centralizing the telephony infrastructure across Europe allows T-Systems to create a combined IP system.

Getting Europe on the line.

Organizations can cut down on aggravation and expense by centralizing their telephony infrastructure, particularly if they cast their nets wider than a single country. One key building block: a central SIP gateway for Europe.
Author: Yvonne Nestler
Photos: iStockphoto
It was once the queen of telephony, the ultimate symbol of long-distance communications. Today, the telephone booth does nothing more than collect dust in large, sepulchral warehouses. It lost its crown first to the cell phone, then to the smartphone. However, technological progress hasn’t just come to people who use phones; it helps those who manage telephony services, too – including organizations. In most cases, their telephony infrastructure is still highly localized, unlike email servers and business applications, which tend to be hosted centrally at a data center. To put this in more concrete terms, each business site has one or more ISDN lines plus a private branch exchange (PBX). It’s a costly set-up, partly because the organization has to maintain each PBX individually and manage or extend phone lines separately. In addition, global organizations have to negotiate with a raft of local phone service providers and satisfy different requirements for each country, including emergency call functions and special regulations.
That’s all changing now – thanks to all-IP. Voice no longer requires dedicated hardware. Instead, it runs on servers as an application and communicates over data networks, just like email. Its name: voice over IP (VoIP). It doesn’t really matter where the server for this application resides. All locations can use a central PBX and a central SIP gateway – the telephone line of the all-IP age – that are connected over a data network (VPN), which the organization has to have anyway. 

Opportunity for big savings

The benefits are clear: organizations can lower recurring telephony costs by a wide margin while improving security, quality and availability. How? It’s partly because it is easier to maintain a smaller number of PBXs. And it’s because the IT department can manage all the communications services and end devices centrally for the entire enterprise.
With this set-up, business sites only need to connect to the VPN, and not to the public switched telephone network (PSTN). Organizations end up requiring far fewer voice channels to the PSTN for two reasons. First, internal calls stay within the corporate network instead of breaking out to the PSTN through the SIP gateway. Second, since all the sites share the central gateway’s voice channels for external calls, the IT department no longer has to leave as much of a “buffer” for peak calling periods.

Central border guard

Security is better, too. To protect voice communications and data networks, VoIP requires a system to stand guard between the corporate network and the PSTN: a session border controller (SBC). It does a variety of things, from warding off DDoS attacks to supporting the encryption of signaling and voice data to performing important routing functions. If an organization uses one central phone line, it needs only one central session border controller. The SBC not only costs less than buying multiple local components, but also makes it easy to implement highly available VoIP security in a consistent way.
“These benefits are multiplied if you centralize phone lines or SIP trunks for several countries, and not just in one country,” said Hanno Wirth, Voice Services & Marketability TC. To make this possible, T-Systems launched Corporate SIP International in August 2017: a central phone line that currently serves 19 European countries, along with a central network-based enterprise session border controller. Connected sites can make up to 50,000 external phone calls simultaneously. There’s even an option to access a central PBX in a private cloud.

Key functions remain

With Corporate SIP International, organizations need only one partner and one master contract for all their countries instead of juggling umpteen phone service providers per country. T-Systems takes care of rolling out the solution and migrating legacy lines transnationally. All the processes are the same in every country, making it much easier for organizations to manage their telephony across Europe.
At the same time, the solution also satisfies requirements that are specific to each country. It’s still possible, in other words, to keep existing local phone numbers, locate emergency callers and comply with local laws and regulations. If requested, T-Systems will even issue country-specific invoices – in a standardized electronic format to allow direct processing.

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