{"id":2170,"date":"2011-01-14T15:26:08","date_gmt":"2011-01-14T19:26:08","guid":{"rendered":"http:\/\/www.engineeringradio.us\/blog\/?p=3928"},"modified":"2023-09-23T09:34:09","modified_gmt":"2023-09-23T13:34:09","slug":"audio-over-ip-what-is-it-why-should-i-care","status":"publish","type":"post","link":"https:\/\/www.engineeringradio.us\/blog\/2011\/01\/audio-over-ip-what-is-it-why-should-i-care\/","title":{"rendered":"Audio over IP, what is it, why should I care?"},"content":{"rendered":"\n

IP networks are the largest standardized data transfer networks worldwide.\u00a0 These networks can be found in almost every business and home and are used for file transfer, storage, printing, etc.\u00a0 The Internet Protocol<\/a> over Ethernet<\/a> (802.x) networks is widely understood and supported.\u00a0 It is robust, inexpensive, well-documented, readily deployed, and nearly universal.\u00a0 Many equipment manufacturers such as Comrex, Telos, and Wheatstone have developed audio equipment that uses IP networks to transfer and route audio within and between facilities.<\/p>\n\n\n\n

\"IP<\/a>
IP protocol stack<\/figcaption><\/figure>\n\n\n\n

Audio enters the system via an analog-to-digital converter (A\/D converter<\/a>), often a sound card, at which point a computer program stores it as a file.\u00a0 These files can be .wav<\/a>, .mp3<\/a>, .mp4<\/a>, apt-X<\/a>, or some other format.\u00a0 Once the audio is converted to a digital data format, it is handled much the same way as any other digital data.<\/p>\n\n\n\n

IP stands for \u201cInternet Protocol,\u201d which is a communications protocol for transmitting data between computers connected to area networks.\u00a0 In conjunction with a transmission protocol, either TCP<\/a> (Transmission Control Protocol) or UDP<\/a> (User Datagram Protocol) IP forms what is known as the Internet Protocol Suit known as TCP\/IP.\u00a0 The Internet Protocol Suit<\/a> contains four layers:<\/p>\n\n\n\n

    \n
  1. Application layer \u2013 This is the protocol that contains the end-use data.\u00a0 Examples of these would be HTTP, FTP, DCHP, SMTP, POP3, etc.\u00a0 Telos Systems uses its own application called \u201cLivewire\u201d for its equipment.\u00a0 Wheatstone<\/a> uses \u201cWHEATNET.\u201d\u00a0 Digigram<\/a> uses \u201cEthersound.\u201d\u00a0\u00a0 This is an important distinction.<\/li>\n\n\n\n
  2. Transfer layer \u2013 This contains the TCP or UDP header information that contains such things as transmitting, and receiving ports, checksum value for error checking, etc.\u00a0 It is responsible for establishing a pathway through multiple IP networks, flow control, congestion routing, error checking, and retransmission.\u00a0 TCP allows for multiple IP packets to be strung together for transmission, increasing transfer rate and efficiency.<\/li>\n\n\n\n
  3. Internet layer \u2013 This is responsible for transporting data packets across networks using unique addresses (IP addresses).<\/li>\n\n\n\n
  4. Link Layer \u2013 This can also be called the physical layer, using Ethernet (802.x), DSL, ISDN, and other methods.\u00a0 The physical layer also means things like network cards, sound cards, wiring, switches, and routers.<\/li>\n<\/ol>\n\n\n\n

    Advantages:<\/p>\n\n\n\n

    An IP network can be established to transmit data over almost any path length and across multiple link layer protocols.\u00a0 Audio, converted to data can thus be transmitted around the world, reassembled, and listened to with no degradation.\u00a0 Broadband internet connections using a cable, DSL, ISDN, or T-1 circuits can be pressed into service as STL\u2019s, ICR\u2019s, and TSL\u2019s.\u00a0 This translates to fast deployment; no STL coordination or licensing issues, no antennas to install if on a wired network.\u00a0 Cost reductions are also realized when considering this technology over dedicated point-to-point TELCO T-1\u2019s.\u00a0 Additionally, license-free spread spectrum radios that have either DS-1 or 10baseT Ethernet ports can be used, provided an interference-free path is available.<\/p>\n\n\n\n

    IP audio within facilities can also be employed with some brands of consoles and soundcards, thus greatly reducing audio wiring and distribution systems and corresponding expenses.\u00a0 As network speeds increase, file transfer speeds and capacity also increase.<\/p>\n\n\n\n

    Disadvantages:<\/p>\n\n\n\n

    Dissimilar protocols in the application layer mean a facility can\u2019t plug a Barix box into a Telos Xtream IP and make it work.\u00a0 There are likely hundreds of application layer protocols, most of which do not speak to each other.\u00a0 At some point in the future, an IP audio standard, like the digital audio AES\/EBU may appear, which will allow equipment cross-connections.<\/p>\n\n\n\n

    Additionally, the quality of the physical layer can degrade performance over congested networks.\u00a0 The installations must be carefully completed to realize the full bandwidth capacities of cables, patch panels, patch cords, etc.\u00a0 Even something as little as stepping on a Category 6<\/a> cable during installation can degrade its high-end performance curve.\u00a0 The cable should be adequately supported, not kinked, and not stretched (excessive pulling force) during installation.<\/p>\n\n\n\n

    TCP\/IP reliability is another disadvantage over formats like ATM<\/a>.\u00a0 In a TCP\/IP network, no central monitoring or performance check system is available.\u00a0 TCP\/IP is what could be called a \u201cbroadcast\u201d protocol.\u00a0 That is to say, it is sent out with a best-effort delivery and no delivery confirmation.\u00a0 Therefore, it is referred to as a connection-less protocol and in network architecture parlance, an unreliable network.\u00a0 Lack of reliability allows any of these faults to occur; data corruption, lost data packets, duplicate arrival, out of order data packets.\u00a0 That is not to say that is does not work, merely that there is no alarm generated if an IP network begins to lose data.\u00a0 Of course, the loss of data will affect the reconstruction of the audio.<\/p>\n\n\n

    \n
    \"Analog<\/a>
    Analog digital converter symbol<\/figcaption><\/figure>\n<\/div>\n\n\n

    Finally, latency can become an issue over longer paths.  Every A\/D converter, Network Interface Card (NIC), cable, patch panel, router, etc has some latency in its circuitry.  These delays are additive and dependent on the length of the path and the number of devices in it.<\/p>\n\n\n\n

    Provided care is taken during design and installation, AOIP networks can work flawlessly.  Stocking adequate spare parts, things like ethernet switches, NICs, patch cables and a means to test wiring and network components is a requirement for AOIP facilities.<\/p>\n","protected":false},"excerpt":{"rendered":"

    IP networks are the largest standardized data transfer networks worldwide.\u00a0 These networks can be found in almost every business and home and are used for file transfer, storage, printing, etc.\u00a0 The Internet Protocol over Ethernet (802.x) networks is widely understood and supported.\u00a0 It is robust, inexpensive, well-documented, readily deployed, and nearly universal.\u00a0 Many equipment manufacturers … Continue reading Audio over IP, what is it, why should I care?<\/span><\/a><\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[158,306,177],"class_list":["post-2170","post","type-post","status-publish","format-standard","hentry","category-tech-stuff","tag-aoip","tag-audio","tag-ethernet"],"_links":{"self":[{"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/posts\/2170","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/comments?post=2170"}],"version-history":[{"count":13,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/posts\/2170\/revisions"}],"predecessor-version":[{"id":12459,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/posts\/2170\/revisions\/12459"}],"wp:attachment":[{"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/media?parent=2170"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/categories?post=2170"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/tags?post=2170"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}