NetNews Usenet Archive 1992 #27

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Path: sparky!uunet!haven.umd.edu!umd5!macbeth.umd.edu!carl From: carl@umd5.umd.edu (Carl Symborski) Newsgroups: comp.dcom.cell-relay Subject: cell-relay monthly FAQ posting (long) Summary: November FAQ Message-ID: <17164@umd5.umd.edu> Date: 24 Nov 92 03:18:26 GMT Sender: news@umd5.umd.edu Followup-To: comp.dcom.cell-relay Organization: University of Maryland, College Park Lines: 459 Originator: carl@macbeth.umd.edu [Last Updated November 1992] This article contains the answers to some Frequently Asked Questions (FAQ) or general information which is related to or has been seen in comp.dcom.cell-relay. It is posted to provide information of general interest to both new and experienced readers. The FAQ list includes answers to the following questions, which are loosely grouped into categories. Questions marked with a + indicate questions new to this issue; those with significant changes of content since the last issue are marked by *: A) TOPIC: COMP.DCOM.CELL-RELAY BASIC INFORMATION A1) What is the CELL-RELAY group? A2) What is the archive site for this group? A3) Is there a parallel mailing list for this group? A4)* What other mailing lists are related to ATM? B) TOPIC: INDUSTRY FORUMS AND VENDOR INFORMATION B1)* How can I contact the ATM Forum? B2)* What vendors are working on ATM technology? C) TOPIC: ATM REFERENCES C1)* What are some good getting started ATM references? C2) Where/What is the "Network Compatible ATM for LANs" document? C3) Where are hosts with ATM related information? C4)* How can I get the ATM Forum's Interface Specification? C5)+ List of CCITT Recommendations concerning ATM. D) TOPIC: ATM TECHNOLOGY QUESTIONS D1)* What are the various ATM Access layers? D2) Are ATM cells delivered in order? D3) What do people mean by the term "traffic shaping"? D4) What is happening with signalling standards for ATM? E) TOPIC: ATM VS. XYZ TECHNOLOGY E1)* How does ATM differ from SMDS? If you have suggestions or corrections for any of these answers or any additional information, please send them directly to carl@umd5.umd.edu; the information will be included in the next revision (or possibly the one after that). This posting is intended to be distributed once a month. New versions are archived along with other comp.dcom.cell-relay traffic on mythos.ucs.indiana.edu. See subject A2 for instructions to access the archive. The information contained herein has been gathered from a variety of sources. Most derived from a consensus of postings on the group. If you would like to claim responsibility for a particular item, please let me know. Enjoy! Carl Symborski carl@umd5.umd.edu ----------------------------------------------------------------------------- TOPIC: A) TOPIC: COMP.DCOM.CELL-RELAY BASIC INFORMATION ----------------------------------------------------------------------------- SUBJECT: A1) What is the CELL-RELAY group? The purpose of this group is to provide a forum for the submission of articles and inquiries dealing with networks using Cell Relay as a transport; including local, metropolitan, and wide area networks. The name cell-relay was chosen as a compromise over objections to the name "ATM" during the creation of this group. The acronym ATM in the context of this group stands for Asynchronous Transfer Mode, not Automatic Teller Machines or Adobe Type Manager. The term "cell" in cell-relay is taken to mean a small, fixed sized, information bearing unit that provides the foundation for transport and multiplexing of user traffic. This topic area is not related to cellular phones or intra-cellular organisms. SUBJECT: A2) What is the archive site for this group? The archives for comp.dcom.cell-relay are available via anonymous ftp to mythos.ucs.indiana.edu (129.79.17.52) as: pub/cell-relay/archive/YY-MM.mbox where YY=year and MM=month. There are available in both compressed and normal formats. Additionally there is a WAIS-based bibliography of ATM related research papers. This is available on the same host under: pub/cell-relay/bib SUBJECT: A3) Is there a parallel mailing list for this group? A direct mailing list has been setup which is a mirror of the USEnet newsgroup comp.dcom.cell-relay. To send mail TO the list, send it to: comp.dcom.cell-relay@news-relay.indiana.edu To un/subscribe, or send other notes to the list management, please use the address: cell-relay-request@mail-relay.indiana.edu SUBJECT: A4) What other mailing lists are related to ATM? There are three lists described below. One is for an IETF group working on the issue of IP over ATM. This work is on going and primarily focused on that task. General ATM questions and blue-skying are inappropriate and discouraged by the members on the list. To send mail TO the list, send it to: atm@sun.com To un/subscribe, or send other notes to the list management, use the address: atm-request@sun.com Another list is associated with the general problem of IP over large public networks. As with the ATM list above, its purpose is for an IETF working group. The same restrictions apply. To send mail TO the list, send it to: iplpdn@NRI.Reston.VA.US To un/subscribe, or send other notes to the list management, use the address: iplpdn-request@nri.reston.va.us Related to cell-relay technology is the Distributed Queueing mailing list. The distributed queueing list is intended for discussion about protocol design, variants, extensions, associated with the use of DQ for arbitrating access to cells in shared-medium cell-relay networks. To send mail TO the list, sent it to: dqlist@atri.curtin.edu.au To un/subscribe, or send other notes to the list management, use the address: dqlist-request@atri.curtin.edu.au ----------------------------------------------------------------------------- TOPIC: B) INDUSTRY FORUMS AND VENDOR INFORMATION ----------------------------------------------------------------------------- SUBJECT: B1) * How can I contact the ATM Forum? Similar to the Frame Relay Forum, the ATM Forum is an open public forum with over 80 contributing and auditing companies. Membership includes many international companies. Some companies also participate in ANSI T1S1 and other standards bodies. Those interested in joining the forum or needing additional information shoud contact the ATM Forum's secretariat, Interop Inc at (415) 941-3399. The ATM Forum Hotline number is (415) 941-0849. Audit membership of the Forum is $1000/year. SUBJECT: B2) * What vendors are working on ATM technology? It is tough to get a number on this. There are a few companies with hardware they can demonstrate. More who have made product announcements. Many more who have stated product intentions. Some are building big central office switches, others smaller ones for the LAN market. Workstation vendors are working on ATM interface boards. Chip companies are working on ATM chip sets, etc. Some switch vendors mentioned on this list with hardware available this year include Fore Systems, Adaptive, MPR Teltech Ltd., and Nokia Telecommunications just to name a few. Naturally the big telco switch vendors (NEC, Hitachi, etc.) are developing big central office type switches. In addition there is a group in North America working on low-cost SONET-based ATM physical layer chips for local nets using optics and twisted pair interfaces. This group is called the Saturn Development Group, and consists of PMC-Sierra, Sun Microsystems, Ungermann-Bass, Bell-Northern Research, Interphase, Optical Data Systems, SynOptics Communications, Newbridge, Themis Computer, BBN, MPR Tetltech, and the University of British Columbia. Adaptive designed an ATM/AAL chipset for use in equipment (computer, workstation, router, etc.) which connects to an ATM network. That chipset is now licenced to two chip manufacturers, TransSwitch and National Semiconductor. ----------------------------------------------------------------------------- TOPIC: C) ATM REFERENCES ----------------------------------------------------------------------------- SUBJECT: C1) * What are some good getting started ATM references? Generally it is hard to pick up any communications related technical journal, conference, or trade publications and not find something about ATM. Most of what has been written in the 1985 through 1990 time frame primarily deals with the application of ATM to Broadband ISDN. These provide the foundation on which other applications of ATM have been based and therefore should not be over looked. Note that because of the pace of ATM standardization, reference books rapidly become out-of-date. Specifically, there have been major changes to the specification of the AALs subsequent to the publication of these books and articles. However, the following references do offer a good base of background information. --General: "Data Communications Special Guide", IEEE Spectrum, 8/91, p.22. o Hi-level overview of high-speed lans, wans, bisdn, atm, with glossary and bibliography. IEEE Communications Magazine, April 1992, VOL. 30, NO. 4 o This is a special issue with six articles on gigabit networks technology. "Cell Relay Switching", Data Communications, 9/91, p.58. o Looks at cell relay and switching in general, not just ATM. Rainer Handel and Manfred Huber. "Integrated Broadband Networks: An Introduction to ATM-Based Networks". Addison-Wesley, 1991. ISBN 0-201-54444-X. 230 pp. --ATM: "Overview of ATM Networks: functions and procedures", Computer Communications, 12/91, p.615. o Cell headers, bit definitions and the like. 33 References, including good list of CCITT recommendations. "Broadband ISDN and Asynchronous Transfer Mode (ATM)", IEEE Communications, 9/89. o Describes most of the jargon as well as the paradigm and unresolved issues. One point to note is that the article is fairly old (1989) and some things have changed. For example, the ATM cell headers described are no longer valid. "Asynchronous Transfer Mode: Solution for Broadband ISDN", Martin de Prycker, Ellis Horwood, New York, 1991. ISBN 0-13-053513-3 --SWITCH FABRICS: These papers offer a fast jump start on ATM switch architectures, design issues and tradeoffs. H. Ahmadi and W. Denzel, "A Survey of Modern High-Performance Switching Techniques", IEEE J on Selected Areas in Comm, Vol. 7, No. 7, Sept 1989, p. 1091-1103 F. Tobagi, "Fast Packet Switch Architectures for Broad-band Integrated Services Digital Networks", Proceedings of IEEE, Vol. 78, No. 1, Jan. 1990, p. 133-167 Joseph Y. Hui, "Switching and Traffic Theory for Integrated Broadband Networks", Kluwer Academic Publishers, 1991, ISBN 0-7923-9061-X o A back to basics text book explaining core switching concepts like batcher/banyon, clos, min, buffering, etc. SUBJECT: C2) Where/What is the "Network Compatible ATM for Local Network Applications" document? "Network Compatible ATM for Local Network Applications", V1.0, April 3, 1992. A proposal for a 150 Mb ATM LAN from Apple, Bellcore, Sun and Xerox. Available in standard postscript and compressed standard postscript from: thumper.bellcore.com: /pub/nclatm/nclatm.ps /pub/nclatm/nclatm.ps.Z ftp.apple.com: /pub/latm/nclatm.ps /pub/latm/nclatm.ps.Z parcftp.xerox.com: /pub/latm/nclatm.ps /pub/latm/nclatm.ps.Z SUBJECT: C3) Where are hosts with ATM related information? Here's a list of sites that that seem to cater to the ATM/broadband/real-time continuous-media crowd: cc-hw.bbn.com Rec_I_cls.ps, Rec_I_cls.hqx icsi-ftp.Berkeley.EDU Research, Continuous media wuarchive.wustl.edu Research, ATM Hardware datanet.tele.fi Standards drafts lcs.mit.edu ?? nsco.network.com HIPPI gregorio.stanford.edu IP Multicast (Source: Allen Robel, robelr@mythos.ucs.indiana.edu) SUBJECT: C4) * How can I get the ATM Forum's Interface Specification? The ATM Forum has produced a document called the User-Network Interface specification. For those which are not ATM Forum members, hard copy can be obtained for a nominal reproduction fee from the ATM Forum's secretariat, Interop Inc. See information listed under topic B1 for how to contact the ATM Forum. SUBJECT: C5) + List of CCITT recommendations concerning ATM This list is provided for informational purposes only. No guarentee as to its completeness or correctness. Also, although they are not formally published, many of the following recommendations have been substantially updated since first published. If you can find a CCITT participant you should try to get the later versions, which are very close to frozen. The translated versions will be tabled at the Plenary Assembly in June 1993 for approval to publish. You can buy these on paper from the ITU: ITU Place des Nations CH-1211 Geneva 20 Switzerland. The fax number of the sales office is +41 22 730 5194. They are also available commercially from at least 2 sources in the U.S.: Information Gatekeepers in Boston, MA (1-800-323-1088) Phillipps Publishing (1-800-OMNICOM) Phillips usually has documents in stock & has fast delivery. =CCITT Recommendations Concerning ATM = E.164 Numbering plan for the ISDN era 08/91 G.707 Synchronous digital hierarchy bit rates 04/91 G.708 Network node interface for the synchronous 04/91 digital hierarchy G.709 Synchronous multiplexing structure 04/91 I.150 !! B-ISDN asynchronous transfer mode functional 04/91 characteristics I.211 !! B-ISDN service aspects 04/91 I.311 !! B-ISDN General Network aspects 04/91 I.321 B-ISDN protocol reference model and its 04/91 application I.327 B-ISDN functional architecture 04/91 I.330 ISDN numbering and addressing principles 1988 I.332 Numbering principles for interworking between 1988 ISDNs and dedicated networks with different numbering plans I.361 !! B-ISDN ATM layer specification 04/91 I.362 !! B-ISDN ATM adaptation layer (AAL) functional 04/91 description I.363 !! B-ISDN ATM adaptation layer (AAL) specification 04/91 I.413 B-ISDN user-network interface 04/91 I.432 B-ISDN user-network interface - Physical layer 04/91 specification I.610 !! OAM principles of the B-ISDN access 04/91 Q.11 bis Numbering plan for the ISDN era 1988 Q.11 ter Timetable for coordinated implementation of the 1988 full capability of the numbering plan for the ISDN era (Recommendation E.164) Q.931 ISDN user-network interface layer 3 1988 specification for basic call control Those marked with !! are being revised through the efforts of Study Group XVIII, Questions 2, and 13. Certainly the others are being updated as well. Also, there are two new Recommendations yet to be published: I.364 Temp Doc 58 (XVIII) 'Support of Broadband Connectionless Data Service on B-ISDN' I.371 Temp Doc 64 (XVIII) 'Traffic Control and Congestion Control in B-ISDN' ----------------------------------------------------------------------------- TOPIC: D) ATM TECHNOLOGY QUESTIONS ----------------------------------------------------------------------------- SUBJECT: D1) * What are the various ATM Adaptation layers? In order for ATM to support many kinds of services with different traffic characteristics and system requirements, it is necessary to adapt the different classes of applications to the ATM layer. This function is performed by the AAL, which is service-dependent. Four types of AAL were originally recommended by CCITT. Two of these have now been merged into one. Also, within the past year a fifth type of AAL has been proposed. Briefly the four ATM adaptation layers (AAL) have/are being defined: AAL1 - Supports connection-oriented services that require constant bit rates and have specific timing and delay requirements. Example are constant bit rate services like DS1 or DS3 transport. AAL2 - Supports connection-oriented services that do not require constant bit rates. In other words, variable bit rate applications like some video schemes. AAL3/4 - This AAL is intended for both connectionless and connection oriented variable bit rate services. Originally two distinct adaptation layers AAL3 and 4, they have been merged into a single AAL which name is AAL3/4 for historical reasons. AAL5 - Supports connection-oriented variable bit rate data services. It is a substantially lean AAL compaired with AAL3/4 at the expense of error recovery and built in retransmission. This tradeoff provides a smaller bandwidth overhead, simpler processing requirements, and reduced implementation complexity. Some organizations have proposed AAL5 for use with both connection-oriented and connectionless services. A recent document which describes these (except AAL2) with frame formats is: "Asynchronous Transfer Mode (ATM) and ATM Adaptation Layer (AAL) Protocols Generic Requirements", Bellcore Technical Advisory, TA-NWT-001113, Issue 1, August 1992. This can be obtained by writing to: Bellcore Document Registrar 445 South Street - Rm. 2J125 P.O. Box 1910 Morristown, NJ 07962-1910 SUBJECT: D2) Are ATM cells delivered in order? Yes. The ATM standards specify that all ATM cells will be delivered in order. Any switch and adaptation equipment design must take this into consideration. SUBJECT: D3) What do people mean by the term "traffic shaping"? Traffic shaping is forcing your traffic to conform to a certain specified behavior. Usually the specified behavior is a worst case or a worst case plus average case (i.e., at worst, this application will generate 100 Mbits/s of data for a maximum burst of 2 seconds and its average over any 10 second interval will be no more than 50 Mbit/s). Of course, understand that the specified behavior may closely match the way the traffic was going to behave anyway. But by knowing precisely how the traffic is going to behave, it is possible to allocate resources inside the network such that guarantees about availability of bandwidth and maximum delays can be given. (Source: Craig Partridge, craig@bbn.com) A variety of techniques have been investigated to implement traffic shaping. Reference the literature for keywords such as "leaky bucket", "congestion", "rate control", "policing". SUBJECT: D4) What is happening with signalling standards for ATM? The ATM Forum Technical Committee has a Sub-Working Group that is actively working on signalling. Most ATM LAN vendors, including Fore Systems are members of this Sub-Working Group. Currently focus is in discussing the requirements for signalling in private ATM networks. Additionally, the ANSI T1S1 as well as the CCITT sudygroup XI are concerned with ATM signalling. An observation would lead one to believe that because of the frequency of meetings of The ATM Forum, work may progress more rapidly than work in T1S1 and CCITT. ----------------------------------------------------------------------------- TOPIC: E) TOPIC: ATM VS. XYZ TECHNOLOGY ----------------------------------------------------------------------------- SUBJECT: E1) * How does ATM differ from SMDS? SMDS is a service offering interface from Bellcore. SMDS provides a datagram service, where a packet has about a 40-octet header plus up to 9188 octets of data. The packets themselves may or may not be transported within the network on top of a connection-oriented ATM service. SMDS uses E.164 (ISDN) addresses. The Subscriber Network Interface (SNI) is currently defined to use IEEE 802.6 Distributed Queue Dual Bus (DQDB) access across the SMDS user-network interface. DQDB itself is a form of cell relay. The lower layers of SMDS fragment the packets into cells with a 5-octet header and 48-octet payload. The payload itself has a 2-octet header, 44-octets of data, plus a 2-octet trailer. An SMDS cell therefore is nearly identical in form to an AAL3/4 cell.