Cableservice provider are face a troublesome obstacle . Consumer demand for bandwidth is approaching – and in some cases exceeding –networkcapacity . Many cable companies extend a wide range of services , including cabletelevisionprogramming , digitalvideoand audio TV channel , high definition(HD ) television channels , video on demand(VOD ) , cable modemInternetservices and digitalphoneservice . While coaxial andfiber - opticsystems have a relatively large bandwidth mental ability , service can suffer if too many client are using it at the same fourth dimension . cable television service companies are consider several choice to suffer customer needs , includingswitched digital video(SDV ) .
To understand how SDV function , we ’ll first want a quick lesson on how cable television service companies traditionally ply service to customers . In older cable systems , the cable television company broadcasts every channel in a individual stream of programming to every section of its web all the time . When you use yourset - top box(STB ) to tune to a particular channel , the STB look the stream for the channel ’s frequence and carries the signal to your television .
Because the cable television company sends every channel through the entire web , there ’s not much spare bandwidth available for net divine service or digital telecasting groove . High definition channels take up more bandwidth than normal digital telecasting , so spare bandwidth diminution as cable company add HD channels to their lineups . Because HDTVs have become more affordable and more house have acquired them , demand for HD computer programming has increased . cable’s length society have to discover way to encounter customer expectations , particularly in light of the fact that HD television providers already volunteer dozens of epithelial duct in HD data formatting .
Switched digital TV uses a unlike deliverance scheme . or else of combining all communication channel into one programming flow throughout the connection , the line party selects only the most democratic channels for a meshwork - wide stream . For less pop computer programing , the company respond to individual customer demands as the client tunes in to that epithelial duct . In other words , the service provider sends only the channel customer are actually trying to watch . Because the system only sends customer - demanded communication channel , there ’s a band of spare bandwidth pass on over for other services .
According to IneoQuest , a party that offers SDV solutions to transmission line companies , around 80 percent of all viewers in a give area are watching the same top 20 epithelial duct [ source : Switched Digital Video Solutions ] . Providing only the request channel feeds would free up enough bandwidth for the cable television society to :
In this article , we ’ll examine the architecture and equipment used in an SDV system , and we ’ll learn about the likely advantages and disadvantages of SDV . We ’ll also look at some companies and markets that are already using SDV .
In the next section , we ’ll hear how the SDV system connects the transmission line provider to the customer .
Switched Digital Video Architecture
There is no standardized way to set up an SDV scheme , but every system can be categorized into four sections : theheadend , thetransportsystem , theaccesssystemand thecustomer internet .
Theheadend sectionof SDV architecture is where thevideoandInternetfeed beginning enter the system . It admit the equipment forthwith connected to the cable company :
Some constituent of the headend only flow one way into the system , such as the cable company ’s video provender . Others , like the applications server , pass along back and off with thenetworkto ensure that everything is tend smoothly .
Once the headend converts the video provender into MPEG format and encrypts it , it commit the signal on to thetransport systemof the SDV architecture . The transport organisation ’s purpose is to route the video recording and Internet feeds from the cable ship’s company to the access scheme . This incision consists ofnodes , point where cable connections intersect and limb off , androuters . node and routers redistribute the signal to other node and routers so that the original feed get across the cable company ’s entire customer base . The transport system ’s path connects the headend to the admission system of rules .
Theaccess systemis where the actual digital switch take station . The core of the access system is theSDV waiter . It ’s the SDV server ’s Book of Job to keep data track of customer ' channel change requests . SDV servers are dedicated computers that head for the hills package plan to interpret each channel request . The server sends commands to anEdge Resource Manager(ERM ) and severalEdge QAMdevices to meet demand .
In the next section , we ’ll get word about some of the advantages and disadvantages of SDV overhaul .
Switched Digital Video Advantages and Disadvantages
flip digital video systems ' most obvious advantage is that they cover one of the big problemscablecompanies have – run out of bandwidth . As more masses sign up forHDTVservices , mellow speedcable modemsand VOD , cable companies have to find a way to have . An SDV system helps line company implement a solution without supercede mi of line , since the system can work on top of an subsist substructure .
increase bandwidth can also lead to more avail . A cable companionship could choose to increase the number of channel it offers , allowing it to compete more effectively withsatellite televisioncompanies . extra channels could include more HD feed or programming catered to a particular part .
Cable company provideInternetaccess in much the same way of life they providetelevisionfeeds . fellowship feed Internet downstream through 6 - megahertz ( MHz ) television channel in the cable system bandwidth . Upstream provender , the information sent back through your modem to the Internet , start into a 2 MHz channel . When customer demand bring heavy , the cable television service company creates a Modern 6 megacycle per second transmission channel to relieve accent on the organisation . With SDV , cable company have more bandwidth useable to win over into Internet duct during periods of high customer demand .
A switched digital video system sends only the channels requested by viewers, saving the cable provider bandwidth. Click play to learn more.
SDV systems provide some option that are more important to the cable company than the consumer . Using SDV system , cable company can get more information about what their customers watch over – most SDV systems preserve individual customer secrecy , but they still allow cable troupe to see which channel are in high requirement in various region . Some SDV companies provide systems that would countenance a cable society to direct specific region , or even specific households , with local advertising based on see use . That can be a herculean bargaining chip when the cable television service supplier play with potential advertisers , though consumers might not be as thrilled about it .
Increased bandwidth could also let cable television service companies offer more synergistic options . Let ’s say you ’ve decided to order aboxingmatch pay - per - opinion special . The cable ship’s company could process your petition and send you a subject matter that gives you the option to orderpizzafrom a local eating house . You use yourremote controlto pilot a menu , choose your pizza pie and topping , and substantiate your order . Half an hour later , you ’re watching the pay per aspect and enjoy a hot pizza pie .
The big disadvantage to SDV organization is that there are many component part in the scheme . This think that when problems arise , cable company might detect it difficult to figure out the seed of the issue . trouble could bulge in any section of an SDV system ’s computer architecture , and different trouble require different solution . Problems originating from the client ’s STB will only affect that one household , but a problem with an SDV server or SRM has the potential drop to affect chiliad of customer and might require squad of technicians to get it back on track . In many case , cablegram companies will have to trust on products from multiple vendors to make one SDV system . Some products may have compatibility issues with others , make it gainsay for cable fellowship to give birth reliable service . Even so , SDV systems are an attractive alternative to replacingfiber - opticand coaxal cable with high electrical capacity line .
In the next section , we ’ll take a look at some markets that have SDV systems in place .
Switched Digital Video Market
Companies that plan and produce SDV system components include great names like Scientific Atlanta and Motorola . Some companies build all the components an SDV system needs , but others specialize in specific hardware likeencryptorsorrouters . The variety of products allowscablecompanies to shop around to retrieve the arrangement that full suit client needs and demand .
Because the applied science is relatively new and there ’s potential that job in an SDV system could be difficult to name and correct , implementation has been a gradual cognitive process . Cable company like Comcast Corporation , Time Warner , Cox Communications Inc. and Cablevision Systems Corporation are experiment with SDV equipment by implementing it in select markets [ reservoir : Cable Digital News ] .
These grocery include Cablevision’sNew Yorkmetro region , Time Warner Cable ’s marketplace inAustin , Texas , and Columbia , S.C. , and Comcast ’s market inDenver , Colo. and New Jersey , to name a few . These pilot markets let in millions of cable client , but it ’s still a relatively diminished portion of the whole consumer base . There have n’t been any major issues with the pilot light programme so far . Several cable fellowship be after to implement SDV system in more markets beginning in 2008 .
take for granted the pilot programs work well , we may see cable companies embracing SDV technology over the next few years . It will also take clock time for companies to develop strategy to provide customer support and solve problem when they arise in the internet . This could include hiring adviser to acquire unexampled customer service approach and breeding staff members so that they know how to solve expert issue as they arise .
For client , change might be subtle at first . Some SDV systems can work with existing plant - top box engineering , which means customers wo n’t have to promote their equipment at home . For them , changes could seem to happen overnight . They might find they have a fasterInternetconnection or more channel options . Other systems require new client equipment , which will require existing customers to flip out their STBs .
Every time you change the channel in an SDV system, your set-top box engages in a complex digital conversation with the SDV network. Press play to learn more.
To learn more about switched digital video and related to topics , follow the links on the next Thomas Nelson Page .
