VoIP

Telephone Systems

over IP

Voice services from the ISP

Instead of a telephone system to operate itself, voice services, companies can go to their local Internet provider. Properly enforced, these Centrex services have not been in this country. That could change: flat rate charges for telephone and connections as well as the convergence of IP services offer the chance for a breakthrough.

A ffers of service for voice transmission over the Internet Protocol (VoIP) are numerous and complex.As a common feature of VoIP services through a provider which can be continuously built up line call to the customer. This can be either a fixed connection or a DSL (Digital Subscriber Line) to connect the user for example via a VPN connection (VPN, Virtual Private Network).

Moreover, the way the network termination is an important differentiator. The envisaged telephone system is no longer in his own basement, but the provider. There will decide the scope of services offered. SIP provider (Session Initiation Protocol) networks such as indigo or Freenet, the IP telephony

mainly to provide retail place emphasis on telephony and also provide some

few functions, such as an answering machine. For professional users, it should be but a bit

be more: A very good availability management functions, and via service level agreements (SLA)

verifiable services are available in this league on the request list. The leave as Managed Services, Hosted PBX (Private Branch Exchange) or IP Centrex services designated in accordance with these requirements relate to specific conditions. The prices depend on the availability of services, bandwidth and performance for specific values ​​such as the temporal variation (jitter), or the delay of IP packets (latency). The test is based on SLAs, which document the quality. The outsourcing of the old telephone system assumes control when softswitch providers. The term comes from the softswitch software that allows central control of the switches. Functions such as routes, protocol conversion, resource and bandwidth management, and media gateway controller can be operated with it. The performance and termination of calls, the service provider. He runs the gateway to a public platform and can give priority to individual packets. The customer can monitor and configure their own VPN connections via a management console. For high-quality voice and video services, this technology is state of things - but at a high price. MPLS IP-routing maps to the IP forwarding to any IP packets by a MPLS header (shim header) added. The MPLS header consists of the label for forwarding, the Class of Service field (CoS) to distinguish between classes of service, the bottom-of-stack field (S) and the time-to-live field (TTL ). For MPLS VPNs and traffic engineering multiple labels come in the form of a label stack is used. Administrators configure the MPLS backbone routers.

Unmanaged IP connections

(Via DSL): This is best effort, so the best possible transmission quality.This often means non-guaranteed bandwidth and response times, making some phone calls to remind walkie-talkie connections. In addition, the quality is unpredictable from the utilization of DSL networks. For enterprises, this variant is not recommended, even if the price is relatively low. VoIP in cable networks can be an alternative for companies with cable connection, but is usually more relevant for consumers.There are specific solutions based on GSM, WLAN or WiMAX is currently only for some large corporations or localized closely: VoIP via radio.There are providers who accept managed services as a complete telephone system and operate. This service-oriented approach is ideal for the enterprises in question, which want to outsource their entire telecommunications.The majority of users likely to use SIP services in the foreseeable future. The customer will receive from the providers own telephone number, and thus can then communicate via SIPTelefon. The providers themselves are either operators or have leased capacity. The discontinuation of IP telephone calls from the data to the public

Public Switched Telephone network requires a gateway Telephony Network (PSTN). Many providers offer free calls in their own IP network. The transition to traditional landlines or mobile networks will cost extra - usually as much as the usual fixed-line call-by-call tariffs. Below is a selection of providers to offer the voice services for businesses.

Services for rent

At a fixed monthly price per service and port Computacenter expects from his voice-on-demand solution.

Instead of buying a PBX, the customer pays for the service for a fixed monthly fee and receives an IP telephony infrastructure - including monitoring, maintenance and administration. Both the number and type of devices as well as the respective services are required for this service to their specific requirements. Parts of the existing telecommunications infrastructure can be part of a "soft migration" will. One of the first users of this offer, the call center provider Sellbytel, umrüstet the first 75 extensions to the technique.

The provider Interoute promises its customers 55 percent savings on international calls.Companies, he offers a VPN service for secure data and voice services. This managed service is based on MPLS. Companies can connect traditional or IP-enabled phone systems, and fully converged networks.Besides VoIP, Interoute offers support for Video over IP. The carrier uses in its network softswitches. You assume the voice connections between the different network types and the connection control. A resource and bandwidth management to the required Quality of Service (QoS) guarantee SLAs define the desired availability. Arcor has its managed service offering on behalf of the Company named Arcor IP-telephony.The entire internal communications, including telephone traffic via the IP-VPN of the provider. The common features of traditional telephone systems such as call forwarding, call history, phone numbers and name remain preserved. Moreover, can record the company's internal address and phone books on the corporate server. The MPLS network

also serves as the video communication. Arcor argued with access to data and voice. Existing phone systems can migrate through the prescreening of gateways and provide new services. No investment in hardware, flat rates and manageable costs via the web-based management extensions,

For example, for setting up new users, the benefits of managed services. The Centrex solution is mainly for small and medium-sized companies in question wish to free themselves from dependence on their hardware. Even for small offices / home offices (SOHO), the managed service can be used, for example,

using multi-site team functions. Existing phone numbers can be maintained. 30-50 to implement the features of the phones functions. The Frankfurt Toplink Internet provider has a VoIP product for business customers.Tplpbx with smaller or medium-sized businesses are able to carry voice over IP calls, without sacrificing comfort and functionality need. Variants are available with 5, 10, 25, 50 or 100 extensions. For the version with five unique jobs are € 79 for setup and then to 39 € per month. New extensions can be added at any time, so the telephone system is growing with the company. Companies with home offices and field staff can

log in via the Internet to the telephone system so that the costs for a diversion.

SIP provider

Our Company

Telephone calls between the headquarters and the individual offices of a company are free. The

Telephone system is in the data center with round-the-clock care. Requirement for operating an ADSL, SDSLoder the other faster connection. To the service can be connected to any SIP-enabled phones. The provider operates in the central Internet exchange point DE-CIX Frankfurt, in a soft switch as a transition to the public telephone network. A total of 180 000 students perform on the platform SIPTelefonate.The provider guarantees that ms from the transfer point at DE-CIX, the delay (delay) is less than 10 and lost less than 0.01% of the data packets.After a first attempt using Siemens as the supplier of the supplier Colt is now in a partnership with Avaya.The IP telephony solution COLT IP Voice is based on products such as the Communication Manager, SBS3000-shared blade servers, IP Softphone, IP phones 4625 and 4621, digital phones, 3616 and a voice-mail system, so all the usual functions of a telephone system , also called flat rate, are available.The telephone system is managed in the data centers of the provider or the customer premises. The offer includes several hundred telephony features and functions such as IP softphones to make calls via the computer or the possibility at any location on the same extension to be reachable (hot desking). Additional services such as video telephony, digital voice recording (voice recording) or solutions for connecting fixed and mobile networks are currently under development. Customers such as financial services WCWB in the UK, the

Maertelaere Bank of Belgium or in the city of Amsterdam already use the voice services to Colt. Reductions in telecommunications costs by up to 30 percent to reach Hosted IPT solutions such as British Telecom.The provider uses primarily phones and programs at Cisco. Voice, video and data transport, the IP platform. A variety of service options to choose from, including multimedia (MM) VoIP and VoIP Port. In MM VoIP using voice, multimedia and collaboration applications, the IP infrastructure, VoIP port while the existing telecommunications infrastructure operates on the IP infrastructure and connects the customer with the IPT-hosting platform from BT.

This makes it possible to use new services and protect existing investments. In addition, gradually

IP technology to migrate, for example, at a location to continue to use the existing telecommunications infrastructure,

while other departments already use telephony hosting. Telephony features such as voice messaging, waiting

feature, call forwarding, number portability and caller identification to improve the accessibility of the mobile subscriber.

VoIP from

the MPLS network

The Cologne SDSL provider QSC calls his virtuosic range, the abbreviation for Virtual Office Suite.The Office on Demand

Call Management enables companies without major investment. The basic package provides applications

as the call control (routing personnel), an interactive voice recognition interactive voice response (IVR) and an additional module for telephone conferences. All incoming calls can be time-consuming to caller groups or lead to different ports depending on origin. In this way the subscriber can be reached with a single number. VIP or block lists enable the preferred agencies or by the complete blocking of callers. That is to keep harassment from telemarketing calls (Spam over Internet Telephony, SPIT) within limits. In collaboration with Telefonica, Computacenter is launched.The existing application is extended by Computacenter Telefonica modules, so that individual business locations in the telephone network

can be integrated. The provider manages the centralized and extensible telephone system provides the necessary support. The Hamburg-based network operator Broadnet Mediascape begins with his solution dataVoIP as five participants and 24 months contract period.Advantage is about that hardware updates to confine the virtual IPCentrex system solely on the number of terminals. Everything else, from phone to client to update the firmware of the phones, controls the software centrally and without use of outside service technician. The IPCentrex-

Telephone system of the provider does not require ISDN system telephone lines or other infrastructure, but

relies on symmetric DSLVerbindungen. In addition to normal telephony capabilities of the messaging service provider. Verizon was only launched last year with its VoIP offering. Global Voice VPN with the product to a global VPN solution for the connection of private telecommunications systems (PBX) are associated with traditional forms of national and international business communication. The heart of Global Voice VPN is a database that supports a wide range of call and routing functions for voice, fax and switched data services.

It provides the telephone systems, mobile users and home offices with calls. The provider dns: Net equips

his offer VoIP Centrex: Centrex with unified messaging capabilities, IVR functions, call centers, video and telephone conferences from. The discussions are ongoing about the local area network (LAN) or in larger companies over the VPN connections. The customer only needs IP phones on its own or leased facilities, portable telephones are in a secured wireless connection, which also provides access via a wireless LAN card with the

Notebook allows. About one IPAnbindung to the power of the provider to run the phone calls and Internet connection. The provider operates two identical IP telephone systems. Both call-manager-soft switches are Cisco and are housed in different data centers in Germany. Because of the redundant structure, a failure of one of the two systems or individual components does not affect the stability of the service have.

IP as a market opener

for Centrex?

Despite all the advantages of managed services must first compete in the market. Here are some vendors that something

were quickly forged ahead, caused confusion. Instead of pushing on the price spiral, some providers were

well advised to listen to good corporate clients and to design the products accordingly. Then:

, the expected breakthrough for almost ten years for the technology within reach.

Offer niche

Radio relay terminal

as an alternative to cable

The initial euphoria surrounding the WiMAX wireless standard IEEE 802.16 as an alternative DSL has somewhat abated. Private and corporate customers who can not benefit from a fast DSL connection, must be generally longer than hoped to be patient. In some regions there is Wimax

at least considered as an offer in the niche.

W hen T-Com alone as a market leader in DSL connections (Digital Subscriber Line) of Germany in one

Sufficiency rate of 91 percent of the population speaks and it still offers the other party to come, it sounds huge. But at the same time it means that despite consideration of various alternatives such as cable or satellite, the desire of many Internet users looking for a fast connection remains. High hopes so stoked Wimax. In recent years several regional carriers have installed such wireless networks, but also some of them adjusted again. The reasons are manifold: slow standardization, delayed offer

standardgerechtem of equipment, unclear business model, development of competing technologies. Rapid spread was also previously an open question in the way of license. Originally planned, the Federal Network Agency

(NGN) for the award of so-called broadband wireless access frequencies in the 3.5 GHz band a "Licensing

Light. " Potential operators should agree among themselves, where the spectrum and for which services

uses. Now, in the NGN, but more than 1,200 applications have been received from 102 applicants, of which show, according to spokesman Rudolf Boll of eight, maybe even nine vendors interested in a nationwide WiMAX services. Therefore, it is now but be an auction, where the goal is "the frequency allocation still perform in this year." The primary scope of which peels out of the fixed Internet access. It could

one - from the customer point of view - to offer, especially in rural areas. But even if Matthias Kurth, President of the NGN, in March pleased with the number of applications for previously high-frequency-free regions: The focus of today or will in the near future offerings are planned in urban areas.

Numerous WiMAX

Islands

Currently, there are few WiMax offerings on the market, plus a few field tests or precursors for commercial

Wimax networks: some of Arcor in Kaiserslautern, of St. Augustine and Tcom Swisttal or a project in Düsseldorf.

For Wimax Telecom is "an additional, central key in our commitment to a comprehensive broadband coverage in Germany," such as T-Com Executive Walter Raizner formulated during the Cebit. The company is in his mid-last year launched a pilot project as a classic Wimax DSL supplement. The new method should be used for applications where a DSL line via copper wire is either technically impossible (eg because of too great a distance to the nearest telephone exchange) or not economically feasible (such as to extensive construction work). In the T-Com pilot project, which was valid until March, was given to each of the 100 selected

Customers with a square antenna (about 20 cm x 20 cm) to gain in-house.The downlink transmits around 1 Mbit / s, which corresponds to approximately one standard DSL connection. Tcom made, according to spokesman Ruediger Gräve of good experiences with the technology, and individual customers without DSL coverage Wimax would like to use further.

The company does not yet have Wimax licenses for a regular operation and has applied for the NGN. A further major network operator Arcor in Kaiserslautern since December 2005, a WiMAX network operated in that about half of the metropolitan area - will provide you with a wireless broadband access with VoIP - lie in the fiber optic cables instead of copper cable. The users receive the WiMAX signals with 1 Mbit / s per

Modem, come from where they are in the computer via WLAN. The monthly flat fee of 40 € for the Airmax mentioned offer a flat rate for surfing and a flat rate for nationwide calls to landlines are included. Whether there will be a range of WiMAX Arcor elsewhere, the company can not or will not say yet. The greatest PR machine regarding the German Wimax Broadband Services GmbH (DBD) has set in motion. Under the brand DSLonair is one already for some time now with about two dozen smaller

WiMAX networks, especially in the countryside present. Under the brand MAXXtelekom DBD started in summer 2005 in Heidelberg, and offer business customers in early November 2005 in the "high-desert" Berlin-Pankow, a private client offering. Here is the transfer of up to 3.5 Mbit / s along with Internet telephony from 33,99 € per month

poss However, that in one year the entire city is developed as planned with Wimax, is partly due to technical problems in the stars.A source innovation, and engineering of a major network operator

puts it: "Wimax works best in wooden houses. In concrete structures, it is with the in-house supply

difficult. " Due to licensing, the network planning is tricky. All this comes one year since the cellular

Mobile communications (GSM, UMTS) known, present at the site a building permit for any antenna must.

Delays are therefore to be expected for Wimax. This was demonstrated in practice about the development of WiMAX

Network in Dresden. Here the plan was to take it to the end of June in operation until the problem one location

Thwart the bill made. How DBD spokeswoman Daniela Gutfleisch explains, one must negotiate in addition to a framework agreement with a large housing association contracts for individual properties, is also still involved in the conservation authority. In these days, but now the network will go into operation, and also in terms of a network in Leipzig is one confident to do it later this year. After all, the DBD has been over frequencies from WLL times (Wireless Local Loop), which is also for Wimax

can use. In Heidelberg, for the supply of the city, only a single transmission tower was necessary, and here comes Intel's Rosedale WiMax chip set used. Speaking of Intel: The Americans attack the DBD financially strong under the arms so that the new operator can show the necessary structure for the network triple-digit million amount. In return, the DBD is a Wimax equipment from Intel. In July ordered the DBD, the appearance of their new WiMAX deals: While the proposed rural DSLonair offer under this name will continue, the current offer is now MAXXtelekom MAXXonair. These two brands are to be public now presents "pure DSL" in "an aggressive campaign" under the slogan as "the first unbundled DSL offering in Germany, which provides customers with a DSL alternative they can use without a landline connection." A brand new WiMAX offering is the Televersa Online GmbH in southeast Bavaria. It has been built there by its own account as a combination of a radio network and WLL Wimax and starts as a supplement to existing DSL offerings. The network of Televersa to "the first nationwide WLL / WiMAX network in Germany for a large region," be. The catchment area covers an area of more than 20 000 km 2 with about2.5 million inhabitants. Televersa will thus amount to 95 percent of all households and

Companies and 98 percent of the area to reach, while the DSL service in this region now accounting for only 60 percent of households, and each of the area. In addition, it should not be complicated for the customer to go to radio instead of using a combination of splitter and router DSLModem the Internet. With regard to prices will be inspired by the tariffs and DSL-based solutions, but remain below the prices of T-Com. Televersa has put in his flying-called DSL offer different packages, subdivided for residential and business customers.

The latter is called the Flying-DSL Business, and is divided again in Business Class with bandwidths 2 to 6 Mbit / s and First Class with belt widths from 4 to 10 Mbit / s as SDSL, fixed IPAdressierung for Network Solutions

and indefinite duration connection. To do this you also campaigning with the possibility of individual solutions and

Service Level Agreements (SLA).

Little equipment,

high prices

In previous years, were mainly smaller producers in the subject Wimax. The largest offering is for

WiMAX equipment in the 3.5 - GHz range, because this band is first available in most European countries, or will be.Already certified devices are designed for the IEEE standard 802.16-2004 (Fixed WiMAX) available. Among the major manufacturers including Alvarion, Aperto and Airspan. For IEEE 802.16-2005 (Mobile WiMAX) takes dieAuswahl still modest. At press time it met only a subset of Samsung WiBro. Besides the small producers have now but also the great of the fledgling broadband industry technology discovered for themselves. Several cooperating with Intel, including Alcatel, Siemens and Nokia. Siemens has since mid-March at an appropriate Wimax solution. The Gigaset 461 is a WiMAX modem with integrated router functionality and creates new services like video on demand, video streaming or VoIP from the data stream. To reduce the dominance of Intel a little, the Japanese manufacturer Fujitsu has the end of April 2005 SystemOn-Chip (SoC) implementation of Wimax to MB87M3400 Basisund presented to client stations. It is comparable to the Rosedale chipset from Intel. Both start at quantities of 1,000 copies at $ 45 and to the delivery of affordable WiMAX

Speed ​​devices, which still cost 300-500 U.S. $. As envisioned limit are $ 200.

The comparatively high prices, especially in relation to wireless equipment, dampen demand. And so the forecasts for WiMAX from very different. A euphoric analysis of telecom market research firm view predicts a market value of 53 billion U.S. $ for the next five years. During the same period to 65 billion dollars in flow structure and marketing of WiMAX services. Wimax in Asia will rise even to the key technology.  When looking at Europe but promptly follows the first "buts." Here, namely, investment in UMTS and HSDPA (HSUPA future too) are so high that Wimax will hardly play a dominant role in wireless or mobile broadband. The OECD warned in its report by mid-March from a too large Wimax euphoria. Due to the lengthy and frequency allocation of frequencies already used in many countries it is questionable what role this technique will eventually. Nevertheless, the market for mobile WiMax could Breitbandlösu lengths find a niche, such as the supply of sparsely populated areas where is not worth laying new copper or fiber optic cable. Is also due to linkage of Wi-Fi quite islands Wimax are good, the replacement of WLANs by contrast, holds WiMax is unlikely, because it worked well locally.

Wimax is not a

cellular network

Especially the expectations of the mobile WiMAX IEEE 802.16-2005 standard was high. Some market observers said, even two years ago by a UMTSErsatz and put the investment in 3G technology in question. Ian Keene, research vice president at the Gartner Group, however, absorbs excessive hopes and believes that Mobile WiMAX "more of a dream" was. As the technical challenges of this variant, the heat generation in the recipients, their power consumption and shift the wavelength of the Doppler effect for moving receivers are mentioned. Additional difficulty is the incompatibility between devices

with support for fixed and mobile Wimax Wimax. Other stumbling blocks are the standardization of terminal equipment, the handover between WiMAX cells, roaming issues and the international release of certain frequencies. It was precisely

here expected the German Wimax market impulses from the auction of WiMAX spectrum by the Federal Network Agency.