KOMUNIKASI DATA-konsep kerja Pbx pada server softswitch konsep kerja. Pbx pada server softswitch. Kebutuhan Perangkat VOIP. Voice over Internet Protocol (juga disebut VoIP, IP Telephony, Internet telephony atau Digital Phone) adalah teknologi yang memungkinkan percakapan suara jarak jauh melalui media internet.
BAB 11VoIPVoice over Internet Protocol ( VoIP) is a general term for a family of transmission technologies for delivery of voice communications over networks such as the or other. Other terms frequently encountered and synonymous with VoIP are IP telephony, Internet telephony, voice over broadband (VoBB), telephony, and broadband phone.Internet telephony refers to communications services—voice, facsimile, and/or voice-messaging applications—that are transported via the Internet, rather than the (PSTN). The basic steps involved in originating an Internet telephone call are conversion of the analog voice signal to digital format and compression/translation of the signal into (IP) packets for transmission over the Internet; the process is reversed at the receiving end.VoIP systems employ session control protocols to control the set-up and tear-down of calls as well as which encode speech allowing transmission over an IP network as via an. Codec use is varied between different implementations of VoIP (and often a range of codecs are used); some implementations rely on and, while others support codecs. Contents.History.
1974 - The (IEEE) published a paper entitled 'A Protocol for Packet Network Interconnection.' Example of VoIP adapter setup in residential networkA major development starting in 2004 has been the introduction of mass-market VoIP services over services, in which subscribers make and receive calls as they would over the. Full phone service VoIP phone companies provide inbound and outbound calling with. Many offer unlimited calling to the U.S., and some to Canada or selected countries in Europe or Asia as well, for a flat monthly fee as well as free calling between subscribers using the same provider. These services have a wide variety of features which can be more or less similar to traditional.There are three common methods of connecting to VoIP service providers. A typical analog telephone adapter (ATA) for connecting an analog phone to a VoIP provider.
An (ATA) may be connected between an IP network (such as a broadband connection) and an existing telephone jack in order to provide service nearly indistinguishable from PSTN providers on all the other telephone jacks in the residence. This type of service, which is fixed to one location, is generally offered by broadband Internet providers such as cable companies and telephone companies as a cheaper flat-rate traditional phone service.
Dedicated are phones that allow VoIP calls without the use of a computer. Instead they connect directly to the IP network (using technologies such as or ).
In order to connect to the PSTN they usually require service from a VoIP service provider therefore most people also use them in conjunction with a paid service plan. A (also known as an Internet phone or Digital phone) is a piece of software that can be installed on a that allows VoIP calling without dedicated hardware. This section needs additional for.Please help by adding. Unsourced material may be. (January 2009)Quality of ServiceBecause the underlying IP network is inherently unreliable, in contrast to the circuit-switched public telephone network, and does not inherently provide a mechanism to ensure that data packets are delivered in sequential order, or provide (QoS) guarantees, VoIP implementations face problems mitigating and.Voice travels over IP networks in packets in the same manner as data, so when you talk over an IP network your conversation is broken up into small packets. These voice and data packets travel over the same network with a fixed.
This system is more prone to congestion and than traditional systems.Fixed delays cannot be controlled (as they are caused by the physical distance the packets travel), however some delays can be minimized by marking voice packets as being delay-sensitive (see, for example, ). Fixed delays are especially problematic when satellite circuits are involved, due to long round-trip propagation delay (400–600 milliseconds for links through ).A cause of packet loss and delay is congestion, which can be avoided by means of.The receiving node must restructure IP packets that may be out of order, delayed or missing, while ensuring that the audio stream maintains a proper time consistency. Variation in delay is called. The effects of jitter can be mitigated by storing voice packets in a jitter upon arrival and before producing analog audio, although this further increases delay.
This avoids a condition known as, in which the is missing audio since the next voice packet has not yet arrived. When IP packets are lost or delayed at any point in the network between VoIP users there will be a momentary of voice if all packet delay and loss mechanisms cannot compensate.It has been suggested to rely on the packetized nature of media in VoIP communications and transmit the stream of packets from the source phone to the destination phone simultaneously across different routes (multi-path routing). In such a way, temporary failures have less impact on the communication quality. In it has been suggested to use at the packet level or particularly for transmitting extra redundant packets making the communication more reliable. A number of protocols have been defined to support the reporting of QoS/QoE for VoIP calls.
These include RTCP XR (RFC3611), SIP RTCP Summary Reports, H.460.9 Annex B (for H.323), H.248.30 and MGCP extensions. This section is written like and may require. Please by rewriting it in an.
(April 2009)The nature of makes it difficult to locate network users geographically., therefore, cannot easily be routed to a nearby call center. Sometimes, VoIP systems may route emergency calls to a non-emergency phone line at the intended department. In the United States, at least one major police department has strongly objected to this practice as potentially endangering the public.A fixed line phone has a direct relationship between a telephone number and a physical location. A telephone number represents one pair of wires that links a location to the telco's exchange.
Once a line is connected, the telco stores the home address that relates to the wires, and this relationship will rarely change. If an emergency call comes from that number, then the physical location is known.In the IP world it is not so simple. A broadband provider may know the location where the wires terminate, but this does not necessarily allow the mapping of an IP address to that location. IP addresses are often dynamically assigned, so the may allocate an address for online access, or at the time a broadband router is engaged. The ISP recognizes individual IP addresses, but does not necessarily know what physical location to which it corresponds. The broadband service provider knows the physical location, but is not necessarily tracking the IP addresses in use.There are more complications, since IP allows a great deal of mobility.
For example, a broadband connection can be used to dial a that is employer-owned. When this is done, the IP address being used will belong to the range of the employer, rather than the address of the ISP, so this could be many kilometres away or even in another country. To provide another example: if mobile data is used (e.g. A 3G mobile handset or USB wireless broadband adapter) then the IP address has no relationship with any physical location, since a mobile user could be anywhere that there is network coverage, even roaming via another cellco.In short there is no relationship between IP address and physical location, so the address itself reveals no useful information for the emergency services.At the VoIP level, a phone or gateway may identify itself with a registrar by using a username and password.
So in this case, the Internet Telephony Service Provider knows that a particular user is online, and can relate a specific telephone number to the user. However, it does not recognize how that IP traffic was engaged. Since the IP address itself does not necessarily provide location information presently, today a 'best efforts' approach is to use an available database to find that user and the physical address the user chose to associate with that telephone number-clearly an imperfect solution.VoIP (E911) is another method by which VoIP providers in the United States are able to support emergency services. The VoIP E911 emergency-calling system associates a physical address with the calling party's telephone number as required by the Wireless Communications and Public Safety Act of 1999.
All 'interconnected' VoIP providers (those that provide access to the system) are required to have E911 available to their customers. VoIP E911 service generally adds an additional monthly fee to the subscriber's service per line, similar to analog phone service. Participation in E911 is not required and customers can opt-out or disable E911 service on their VoIP lines, if desired. VoIP E911 has been successfully used by many VoIP providers to provide physical address information to emergency service operators.One shortcoming of VoIP E911 is that the emergency system is based on a static table lookup. Unlike in cellular phones, where the location of an E911 call can be traced using or other methods, the VoIP E911 information is only accurate so long as subscribers are diligent in keeping their emergency address information up-to-date.
In the United States, the Wireless Communications and Public Safety Act of 1999 leaves the burden of responsibility upon the subscribers and not the service providers to keep their emergency information up to date.A tragic example of a miscommunication with VoIP is the death of 18-month-old Elijah Luck in, Canada. In an emergency, services were called. An ambulance was sent to the former home of the Lucks. The VoIP telephone company knew the correct address, as they were paying their bill from the correct current billing address the company had on record. 'It's up to subscribers to ensure the company has up-to-date contact information' was the response from the VoIP company. After about a half hour wait, the Lucks called from a neighbour's land line, whereupon emergency services arrived in six minutes.
Elijah Luck was pronounced dead at the Alberta Children's Hospital.Number portability(LNP) and (MNP) also impact VoIP business. In November 2007, the in the United States released an order extending number portability obligations to interconnected VoIP providers and carriers that support VoIP providers. Number portability is a service that allows a subscriber to select a new telephone carrier without requiring a new number to be issued. Typically, it is the responsibility of the former carrier to 'map' the old number to the undisclosed number assigned by the new carrier.
This is achieved by maintaining a database of numbers. A dialed number is initially received by the original carrier and quickly rerouted to the new carrier.
Multiple porting references must be maintained even if the subscriber returns to the original carrier. The FCC mandates carrier compliance with these consumer-protection stipulations.A voice call originating in the VoIP environment also faces challenges to reach its destination if the number is routed to a mobile phone number on a traditional mobile carrier. VoIP has been identified in the past as a (LCR) system, which is based on checking the destination of each telephone call as it is made, and then sending the call via the network that will cost the customer the least. This rating is subject to some debate given the complexity of call routing created by number portability. With number portability now in place, LCR providers can no longer rely on using the network root prefix to determine how to route a call.
Instead, they must now determine the actual network of every number before routing the call.Therefore, VoIP solutions also need to handle MNP when routing a voice call. In countries without a central database, like the UK, it might be necessary to query the network about which home network a mobile phone number belongs to. As the popularity of VoIP increases in the enterprise markets because of options, it needs to provide a certain level of reliability when handling calls.MNP checks are important to assure that this quality of service is met. By handling MNP lookups before routing a call and by assuring that the voice call will actually work, VoIP service providers are able to offer business subscribers the level of reliability they require.In countries such as Singapore, the most recent solution is expected to open the doors to new business opportunities for non-traditional telecommunication service providers like wireless broadband providers and voice over IP (VoIP) providers.PSTN Integrationis a global numbering standard for both the. Most VoIP implementations support to allow calls to be routed to and from VoIP subscribers and the PSTN/PLMN.
VoIP implementations can also allow other identification techniques to be used. For example, Skype allows subscribers to choose 'Skype names' (usernames) whereas SIP implementations can use similar to.
Often VoIP implementations employ methods of translating non-E.164 identifiers to E.164 numbers and vice-versa, such as the Skype-In service provided by Skype and the service in IMS and SIP.Echo can also be an issue for PSTN integration. Common causes of echo include in analog circuitry and acoustic coupling of the transmit and receive signal at the receiving end.SecurityAs a computer-based technology, Voice over Internet Protocol telephone systems (VoIP) are as susceptible to attacks as PCs. This means that who know about these vulnerabilities can institute attacks, harvest customer data, record conversations and break into voice mailboxes.Another challenge is routing VoIP traffic through. Private are used along with firewalls to enable VoIP calls to and from protected networks. Uses a proprietary protocol to route calls through other Skype peers on the network, allowing it to traverse and firewalls.
Other methods to traverse NATs involve using protocols such as or.Many consumer VoIP solutions do not support encryption, although having a secure phone is much easier to implement with VoIP than traditional phone lines. As a result, it is relatively easy to eavesdrop on VoIP calls and even change their content. An attacker with a packet sniffer could intercept your VoIP calls if you are not on a secure.There are open source solutions, such as, that facilitate sniffing of VoIP conversations. A modicum of security is afforded by patented audio codecs in proprietary implementations that are not easily available for open source applications , however such has not proven effective in other fields. Some vendors also use compression to make more difficult. However, real security requires encryption and cryptographic authentication which are not widely supported at a consumer level. The existing security standard (SRTP) and the new protocol are available on as well as various.
It is possible to use to secure VoIP by using. Does not use SRTP, but uses encryption which is transparent to the Skype provider. In 2005, Skype invited a researcher, Dr Tom Berson, to assess the security of the Skype software, and his conclusions are available in a published report.The solution provides for enterprise VoIP networks by applying encryption to the digitized voice stream.Caller IDsupport among VoIP providers varies, although the majority of VoIP providers now offer full caller ID with name on outgoing calls.In a few cases, VoIP providers may allow a caller to the caller ID information, potentially making calls appear as though they are from a number that does not belong to the caller. Business grade VoIP equipment and software often makes it easy to modify caller ID information.
Although this can provide many businesses great flexibility, it is also open to abuse.The 'Truth in Caller ID Act' has been in preparation in the US congress since 2006, but as of January 2009 still has not been enacted. This bill proposes to make it a crime in the USA to 'knowingly transmit misleading or inaccurate caller identification information with the intent to defraud, cause harm, or wrongfully obtain anything of value.' Interconnection to traditional PSTN telephonesSome analog telephone adapters do not decode pulse dialing from older phones. The VoIP user may use a pulse-to-tone converter, if needed.
Fax handlingSupport for sending faxes over VoIP implementations is still limited. The existing voice are not designed for fax transmission; they are designed to digitize an analog representation of a human voice efficiently. However, the inefficiency of digitizing an analog representation (modem signal) of a digital representation (a document image) of analog data (an original document) more than negates any bandwidth advantage of VoIP.
In other words, the fax 'sounds' simply don’t fit in the VoIP channel. An alternative IP-based solution for delivering fax-over-IP called is available.The T.38 protocol is designed to work like a traditional fax machine and can work using several configurations. The fax machine could be a traditional fax machine connected to the PSTN, or an ATA box (or similar). It could be a fax machine with an RJ-45 connector plugged straight into an IP network, or it could be a computer pretending to be a fax machine. Originally, T.38 was designed to use UDP and TCP transmission methods across an IP network.
The main difference between using UDP and TCP methods for a FAX is the real time streaming attributes. TCP is better suited for use between two IP devices.
However, older fax machines, connected to an analog system, benefit from UDP near real-time characteristics.There have been updated versions of T.30 to resolve the fax over IP issues, which is the core fax protocol. Some new fax machines have T.38 built-in capabilities which allow the user to plug right into the network with minimal configuration changes. A unique feature of T.38 is that each packet contains a copy of the main data in the previous packet. This is an option and most implementations seem to support it. This forward error correction scheme makes T.38 far more tolerant of dropped packets than VoIP.
With T.38, two successive lost packets are needed to actually lose any data. The data you lose will only be a small piece, but with the right settings and error correction mode, there is a high probability that you will receive the whole transmission.Tweaking the settings on the T.30 and T.38 protocols could also turn your unreliable fax into a robust machine. Some fax machines pause at the end of a line to allow the paper feed to catch up. This is good news for packets that were lost or delayed because it gives them a chance to catch up. However, were this to happen on every line, your fax transmittal would take a long time. Another possible solution is to treat the fax system as a message switching system, which does not need a real-time data transmission (such as sending a fax as an email attachment (see ) or remote printout (see )).
The end system can completely buffer the incoming fax data before displaying or printing the fax image.Support for other telephony devicesAnother challenge for VoIP implementations is the proper handling of outgoing calls from other telephony devices such as boxes, receivers, systems, conventional and other similar devices that depend on access to a PSTN line for some or all of their functionality.These types of calls sometimes complete without any problems, but in other cases they fail. If VoIP and substitution becomes very popular, some ancillary equipment makers may be forced to redesign equipment, because it would no longer be possible to assume a conventional PSTN telephone line would be available in consumer's homes.Legal Issues. This article is in need of attention from an expert on the subject. Or the may be able to help recruit one.
(November 2008)As the popularity of VoIP grows, and PSTN users switch to VoIP in increasing numbers, governments are becoming more interested in regulating VoIP in a manner similar to PSTN services, especially with the encouragement of the state-mandated telephone monopolies/oligopolies in a given country, who see this as a way to stifle the new competition.Another legal issue that the U.S. Congress is debating concerns changes to the Foreign Intelligence Surveillance Act. The issue in question is calls between Americans and foreigners.
The National Security Agency (NSA) isn't authorized to tap Americans' conversations without a warrant-but the Internet, and specifically voice over Internet protocol, or VoIP, doesn't draw as clear a line to the location of a caller or a call's recipient as the traditional phone system does. So as VoIP's low cost and flexibility convinces more and more organizations to adopt the technology, the line separating the NSA's ability to snoop on phone calls will only get blurrier. VoIP technology has also increased security concerns because VoIP and similar technologies have made it more difficult for the government to determine where a target is physically located when communications are being intercepted, and that creates a whole set of new legal challenges.In the U.S., the now requires all interconnected VoIP service providers to comply with requirements comparable to those for traditional telecommunications service providers. VoIP operators in the U.S. Are required to support; make service accessible to people with disabilities; pay regulatory fees, contributions, and other mandated payments; and enable law enforcement authorities to conduct surveillance pursuant to the (CALEA).
'Interconnected' VoIP operators also must provide service, disclose any limitations on their E-911 functionality to their consumers, and obtain affirmative acknowledgements of these disclosures from all consumers. VoIP operators also receive the benefit of certain U.S.
Telecommunications regulations, including an entitlement to and exchange of traffic with via wholesale carriers. Providers of 'nomadic' VoIP service — those who are unable to determine the location of their users — are exempt from state telecommunications regulation.Throughout the developing world, countries where regulation is weak or captured by the dominant operator, restrictions on the use of VoIP are imposed, including in where VoIP is taxed, Guyana where VoIP is prohibited and India where its retail commercial sales is allowed but only for long distance service. In, where the government is monopolizing telecommunication service, it is a criminal offense to offer services using VoIP. The country has installed firewalls to prevent international calls being made using VoIP. These measures were taken after a popularity in VoIP reduced the income generated by the state owned telecommunication company.In the, the treatment of VoIP service providers is a decision for each Member State's national telecoms regulator, which must use competition law to define relevant national markets and then determine whether any service provider on those national markets has 'significant market power' (and so should be subject to certain obligations).
This section does not any. Please help by adding citations to. Material may be challenged and removed. (January 2009)In Japan, IP telephony ( IP電話, IP Denwa ) is regarded as a service applied by VoIP technology to the whole or a part of the telephone line. As of 2003, IP telephony services have been assigned telephone numbers. IP telephony services also often include videophone/video conferencing services. According to the Telecommunication Business Law, the service category for IP telephony also implies the service provided via Internet, which is not assigned any telephone number.IP telephony is basically regulated by (MIC) as a telecommunication service.
The operators have to disclose necessary information on its quality, etc., prior to making contracts with customers, and have an obligation to respond to their complaints cordially.Many Japanese Internet service providers (ISP) are including IP telephony services. An ISP who also provides IP telephony service is known as a 'ITSP (Internet Telephony Service Provider)'. Pengertian internetInternet berasal dari kata Interconnection Networking yang mempunyai arti hubungan komputer dengan berbagai tipe yang membentuk sistem jaringan yang mencakup seluruh dunia (jaringan komputer global) dengan melalui jalur telekomunikasi seperti telepon, radio link, satelit dan lainnya.Dalam mengatur integrasi dan komunikasi jaringan komputer ini digunakan protokol yaitu TCP/IP. TCP (Transmission Control Protocol) bertugas memastikan bahwa semua hubungan bekerja dengan benar, sedangkan IP (Internet Protocol) yang mentransmisikan data dari satu komputer ke komputer lain. TPC/IP secara umum berfungsi memilih rute terbaik transmisi data, memilih rute alternatif jika suatu rute tidak dapat di gunakan, mengatur dan mengirimkan paket-paket pengiriman data.Untuk dapat ikut serta menggunakan fasilitas Internet, biasanya Anda harus berlangganan ke salah satu ISP (Internet Service Provider) yang ada di kota Anda.
Alamat elektronik Yahoo!Alta VistaLycosWebCrawlerInktomiDejaNewsBimaSakti. Internet Relay Chat (IRC)Internet Relay Chat/IRC merupakan fasilitas untuk komunikasi langsung dengan menggunakan keyboard.
Anda dapat ambil bagian dalam komunikasi publik dengan sekelompok orang. Atau, jika Anda inginkan, Anda dapat menggunakan IRC untuk mengatur komunikasi pribadi dengan orang-orang tertentu, yaitu sejenis teleconference. Internet Phone/ConferenceFasilitas untuk melakukan percakapan jarak jauh via INTERNET.
Untuk itu diperlukan aplikasi khusus dan dukungan hardware multi media. WAIS ServerWAIS (Wide Area Information Service) menyediakan cara lain untuk menemukan informasi yang tersebar dalam INTERNET. WAIS mampu mengakses segala database yang besar (seperti dokumen, file berisi gambar, video dan suara). GopherInternet menyediakan banyak informasi yang dapat diakses penggunanya lewat sistem menu.
Seorang pengguna INTERNET dihadapkan pada sebuah menu yang bercabang-cabang. Untuk menuju ke informasi atau data yang dituju, seorang pengguna menyeleksi pilihan-pilihan yang disediakan hingga masuk ke topik yang diinginkan. Fasilitas demikian disebut Gopher. Mailing ListKelompok diskusi - fasilitas ini dibangun menggunakan teknik yang sama dengan proses penyebaran surat elektronik. Dengan menggunakan fasilitas ini, sebuah berita/file dapat didistribusikan ke banyak pengguna sekaligus.
Bahkan penggunanya dapat melakukan diskusi, seminar, ceramah, konferensi secara elektronik tanpa terikat dimensi ruang dan waktu. Diskusi dapat berlangsung setiap hari tanpa henti. Hasil yang diperoleh akan jauh lebih efektif daripada penyelenggaraan seminar/konferensi konvesional.Daftar alamat Mailing List dengan topik ekonomi. Keterangan Nacubo%[email protected],Keuangan, dan Administrasi ProPerkembangan ekonomi InternasionalEkonomi di negara-negara kurang berkembangEkonomi globaletEkonomi politikBEBERAPA ISTILAH INTERNETBrowserAplikasi yang ada di komputer Anda, mirip dengan aplikasi pengolah kata atau aplikasi lain, yang dirancang untuk membaca tipe file data tertentu. Untuk mengakses WWW, Anda membutuhkan program software internet browser ini.Browsing-metode untuk menjelajahi WWW Internet.
Mem- browse WWW sering disebut sebagai surfing the Net.CU-SeeMeAplikasi yang memungkinkan konferensi video pada Internet.CyberspaceTempat virtual di mana orang dapat berkomunikasi dan bertemu.Domain nameBagian yang membentuk IP address pada Internet. Domain name terdiri dari dua bagian atau lebih yang terpisah oleh tanda titik. Bagian paling kiri adalah bagian yang paling penting, menunjukkan tujuannya.
Contoh: WWW menunjukkan Web server mail. Sembarang domain name akan “melebur” menjadi hanya satu IP address yang unik untuk setiap mesin. Bagian sebelah kanan menunjukkan tipe site. Contoh.gov menunjukkan negara asal site, misalnya id menunjukkan negara Indonesia.E-MailMirip surat pos, tetapi dikirimkan secara elektronik, sehingga tiba ditempat tujuan nyaris dalam tempo seketika itu juga.
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