==Phrack Inc.== Volume One, Issue Eight, Phile #4 of 9 The Integrated Services Digital Network ---==> By Dr. Doom <==--- ISDN or Integrated Services Digital Network has been talked about off and onby AT&T and until now has just been a demented AT&T fantasy, but it is to soonbecome a reality. This phile is the second I have written on the subject andis a cumulation of information from three basic sources :<1> The ISDN AT&T Technical Journal<2> An interview with an AT&T Long Distance Operations Center Supervisor who will be referred to as Mr. R.<3> and some general ISDN articles from Southwestern Bell Newsletters.ISDN Definition===============CCITT Definition : An end to end digital network that supports a wide range ofservices accessed by a set of standard multipurpose user-network interfaces. ISDN will allow for incredible new services that will drastically change thetelecommunications industry and everyone's lives. For example, one new serviceISDN will bring about is calling party identification. This will allowbusinesses and individuals who subscribe to that service to know exactly whatnumber you are calling from before they even decide whether or not to answerthe phone.In the case of dialups like MCI, the originating # will be stored in a computeralong with whatever code and number that person dialed which would greatlyhinder abuse of codes from a home phone. This is just the tip of the iceberg as far as ISDN is concerned. This philewill analyze and describe how The Integrated Services Digital Network willoperate when it is implemented.Out of Band Signalling====================== Essential to a network capable of providing such enhanced services as callingparty identification is out-of-band signalling. Until the late 70's, when AT&Tintroduced the 4ESS toll switch and CCIS into the national network, switcheshad communicated with each other over the same channels in which our voice ordata was transmitted (in-band). During this time, all signalling betweenswitches had to be limited to a type that could be accommodated in the 'voice'channel thus making it impossible to offer any advanced services. The development of the separate Common Channel Interoffice Signaling (CCIS)network allowed for more freedom and flexibility and thus came about the AT&TCalling Card service. ISDN brings an interface from the network to the subscriber's equipment. Thisis a completely digital interface subdivided into two types of channels :The 'D' Channels are those used for sending signalling and control informationacross the interface. The 'B' Channels are those used only for customerinformation which can be in the form of voice, data, or video.The 'D' Channel hence manages the information or 'B' Channels making thesignalling 'out-of-band' and not 'in-band' as it is now. This approach allowsfor two distinct benefits :<1> All the capacity in the information bearing channels is available for customer use.<2> The 'D' Signaling channel allows for distributed processing across the ISDN Network.ISDN Interfaces--------------- The CCITT has defined two major interfaces that will be used in conjunctionwith the 'D' and 'B' channels :The Basic Rate Interface (BRI) consists of one D Channel and two B Channels.This interface is used for locations where information transport is relativelysmall like a residence.The Primary Rate Interface (PRI) consists of one 'D' Channel and 23 'B'Channels. It is used for large capacity vehicles such as PBX's.Notice that there are 2 DIFFERENT 'B' Channels in the Basic Rate Interface.This allows TWO different types of data to be sent over the same connection atthe same time. For example, you could be ULing files to a board on Channel 1while talking to the SYSOP on Channel 2.So, if both you and a board both have a BRI ISDN Interface, next time the SYSOPsays 'Go Voice', you simply pick up the handset, switch it to channel 2, andstart talking...These multiple channels are also the foundation for the widespread use of VideoPhones. Just like you were sending data over channel 1, and talking voice onchannel 2, you can be sending video over channel 1 (allowing the party's to seeeach other) and talking on channel 2.ISDN Devices============ AT&T Technologies, Advanced Micro Devices, and Intel are all in the processof designing equipment that will be compatible with ISDN. So far, the two maindesigns talked about through SWB and AT&T are :<1> The Voice/Data Terminal This will look like any regular computer terminal with the exception that it has a handset on the side of the terminal and a couple of switches that will allow you to decide which channel is for DATA and which channel is for VOICE. This will also (of course), allow two customers with a V/D Terminal to be exchanging DATA over one channel while talking voice over the other one.<2> The Video Phone This is where (yes) Big Brother is arriving... The Video Phone will work pretty much just like it does in Science Fiction movies like 'Aliens' or whatever. If two ISDN customers have video phones, they can talk and see each other or whatever they want to show each other (HAHA) at the same time. Video Phones obviously open up new frontiers for those with entrepreneurial instincts. You can bet there will be some interesting Video Phone Sex lines around... Then, you can have things like 'Dial a Movie...Please enter (1) to view Rambo'..etc... The list goes on. This also leads to a whole new world of problems for the telephone company like 'Obscene Video Calls'. This is again where Calling ID becomes important.Each of these units, and others that will work with ISDN will have some sort ofa special viewing screen that will contain the necessary information aboutincoming calls which includes the originating number and can include suchthings as :<1> The name of the owner of that #<2> The city and state<3> The whole address for that #AT&T ISDN Building Blocks========================= AT&T has designated certain 'building blocks' that will eventually be laid inplace across the entire country to form ISDN.<1> AT&T Communications Service Node------------------------------------ The service node is the customer's gateway to the AT&T Communications nodalfamily of services, including MEGACOM, MEGACOM 800, and Acunet. The firstservice node went into service in 1985 in Philadelphia, PA.<2> Integrated Access--------------------- This allows customers to integrate switched and private line services over asingle DS-1 link to the Service Node.<3> Out-of-Band Signaling------------------------- Discussed earlier.<4> CCS7-------- The CCS7 Common Channel Signaling Network will soon replace CCIS as anout-of-band signalling between AT&T Network Communications Facilities. Becauseof its longer message format and layered structure, the CCS7 will support thenew features.<5> Digital Backbone Network---------------------------- This nationwide AT&T Network includes extensive lightwave and digital radioroutes. By the end of 1988, these Digital Lightwave routes will extend toEurope with the TAT-8 lightwave system, and across the Pacific withHAW-4/TPC-3.<6> Intelligent Software Controlled AT&T Communications Network----------------------------------- This brings about more advanced software related services listed in #1.AT&T ISDN Operations====================Access Transport---------------- Your DS-1 signal is transported from your ISDN equipment to an AT&TCommunications Service Node somewhere. Your line gets to AT&T by tariff from the local exchange carrier (i.e...Southwestern Bell, GTE, or whomever happens to own your local switch...) orAT&T. The direct link to the AT&T Service Node bypasses your local switching.AT&T Service Node----------------- Your local AT&T Service Node is a service office that acts as a gateway toall the new AT&T Nodal ISDN services. This service node is typically composedof :<1> A Refinished 4ESS Switch<2> CNI Ring (Common Net.-Interface)<3> Digital Access and Cross Connect System (DACS)Here is a diagram of how a customer location either goes to a local switch orAT&T's node :Key---CL = Customer Location= = DS-1 Line! = DS-1 Line> = Exiting out to AT&T Network -------- - - **** - Bell - *CL*=======- 5ESS - **** - - -------- ! ! ! ! **** ! *CL* --------!-------- ****===========4ESS=====> - 4ESS= **** - ! ! ! *CL*======DACS=! ! CNI==> **** -DACS ! CNI -DACS= ! - ! 1PSS====> - !=1PSS - ----------------- AT&T Service Node The above diagram shows first how an AT&T Customer with ISDN can eithercontinue service with his local telephone co. or go with a direct link to theAT&T Service Mode. All lines going to an AT&T Service Node whether throughBell or a direct link terminate on either the 4ESS or the DACS. When a line terminates on a DACS it serves as an Integrated AccessDistributor and sends the call to the 1PSS (Packet Switch) for Acunet PacketService or to the 4ESS and then eventually out to the AT&T Network.The AT&T Internodal Network--------------------------- In the internodal network facility, AT&T is in the process of deploying bothdigital lightwave and digital radio systems.Lightguide Systems : In areas where growth is low, the FT3C and FTX180 Single mode terrestriallightguide systems will be used between nodes. On high growth routes AT&T will install fiber pairs at line rates of 1.7Gb/swith 20 mile repeater spacings.Digital Radio : In the digital radio area, 4Gb/s systems such as the TD-90 and the TD-180provide a vehicle for rapid expansion of digital connectivity.ISDN and Digital Switches========================= AT&T has redesigned the 5E Switching Modules in such a way that they arefully compatible with ISDN, but many of the existing 5E's and other switcheswere manufactured without ISDN capability. To meet this need, AT&T hasproduced ISDN interfaces that modularly connect to the system. Here is adiagram of a 5ESS Switching Module with interfaces :Key---$ = ISDN V/D Terminal or Video Phone% = Standard Telephone= = Digital Line< = In-Band LineISLU = Integrated Services Line UnitPSIU = Packet Switch Interface Unit -------------------------- - 5ESS - - Switching - - Module - - - ------------=----=-------- - = = - $====-----======== = - - - = - $====- - --------=--- - -ISLU- - - - %<<<<- ===== PSIU - - - - - - - $====--------------------------The two new hardware additions are :<1> Integrated Services Line Unit and<2> The Packet Switch Interface Unit These units allow a LOCAL 5ESS (or other digital) Switch to serve both ISDNand non-ISDN customers. These interfaces are integrated into a switching modulein a way that will allow ISDN customers to maintain all their previous Bellservices like Local Calling. Notice also that all lines, whether ISDN or not,terminate on the ISLU.Calling Party Identification============================ Discussed briefly in the preface of this phile, the ISDN enhanced CallingParty Identification service offered by AT&T ISDN will be into service alongwith the ISDN. This quote out of the AT&T ISDN Technical reference should give you a goodidea of the impact ISDN will have on hacking and phreaking : 'One example of an enhanced service which has already been included in the ISDN signaling protocol and will have a fundamental impact on day to day telecommunications is the provisions of calling party identification. Calling party ID will help us decide whether or not to answer incoming calls and will minimize instances of nuisance calls and COMPUTER FRAUD via telephone.' Mr. R, our AT&T Supervisor has been attending ISDN Conferences that includerepresentatives from all the major LD Companies (AT&T, MCI, GTE, LDS, etc..),the Regional Bells, and other concerned parties. He said quote 'One of thecontrolling factors behind The Integrated Services Digital Network is thesimple fact that AT&T, MCI, and other long distance companies are losingMILLIONS to Phone Phraud.' Once ISDN is realized, so will network wide CallingParty Identification. Again, our friend Mr. R will enlighten us on the subject of ISDN CallingParty ID and a simple explanation of how it will work : 'Right now, when you pick up the phone in your home, Port Isabel South Western Bell knows that you did. Then, when you dial a number, they know what number you dialed. So they send that information along to us (the AT&T Toll Switch). We then send that along through the network to the person you are calling.'Of course, there is one transaction between AT&T and a Bell Office at the endthat he left off, but if the person or computer you are calling has ISDNCalling Party ID service, your originating # will be sent along the DS-1 LineInterface from Bell to his equipment and show up on his screen after travelingthrough the network like Mr. R described.This is rather simple when you think about it and is one example of how a onceshattered network is working together.Some Sample CP ID Uses----------------------This can be used by large telephone ordering companies to instantly display arecord of that persons credit, previous orders, etc... before the call is evenanswered on the attendant's terminal.When someone logs onto a computer, the originating # is listed on the user logalong with the account name, etc... so that if there is an unauthorized login,they can contact the authorities to do whatever or monitor that number untilthey get enough evidence to prosecute. The same thing holds true with LDDialups. They will record the originating number along with the code and billmaking MCI use rather dangerous.SWB ISDN News============= The following article was extracted from The Southwestern Bell TexasPublication of Telephone Times and is entitled 'User Forum simplifies ISDN' :" Houston---Houston Marketing employees played show and tell with two customersand all three groups are better off for it. Marketing Representatives, with support from Bell Comm. Research, IllinoisBell, AT&T, and McDonald's Corp. met with Shell and Tenneco to discuss ISDN. 'ISDN is an evolving technology' said Bob Campbell, division managermarketing business sales. 'It's still in the developmental stage. These UserForums will give customers input on how it's deployed and what it will looklike.' ISDN is an all digital network that transmits voice and data messagessimultaneously over a single telephone line. 'The User Forums allow customers to share information on specific problemsconcerning implementation, training, customer premise equipment andapplications,' Campbell said. Linda Hobson, manager marketing administrative and coordinator of the event,said not only will User Forums be standard practice in Houston, but probablywill become the national standard. 'We're doing it quarterly here, but as more people become interested, we maymeet more often,' Hobson said. Shell and Tenneco, who have signed letters of intent to purchase ISDN, werespecifically interested in such topics as trial status (SWBT's ISDN trials willbegin soon in St. Louis and Texas), available features, power requirements, andfuture enhancements. 'In the past, we bought the available enhancements, then sold them to thecustomer,' said Hobson. 'That's changing. We have to find out what thecustomer wants, then deliver the service that meets the specific needs'" That concludes the nice little article which by the way, contained someinteresting little tidbits of information.Conclusion========== ISDN is a VERY complicated plan that will drastically change thetelecommunications scene in this country and abroad. Although AT&T has boastedin it's Technical Journals of being able to have its ISDN Capable Networkcompleted by Early 1987, this date seems to keep getting postponed backaccording to our friend Mr. R (The AT&T Supervisor) and he is shooting forlarge scale ISDN no earlier that late 1988 or 1989. Whenever ISDN does becomereality, people will probably just put out files with lists of computers thatsubscribe to ISDN Calling Party Identification, and tell people not to callthem from their home. I hope you have enjoyed reading this phile on ISDN, I will be on the outlookfor more information on it.If you don't already have the # and New User Passwords to Metromedia BBS, sendme (Dr. Doom) mail on any of the boards I am on.
Downloaded From P-80 International Information Systems 304-744-2253 12yrs+
