gamiddleton@watmath.waterloo.edu (Guy Middleton) (10/14/89)
I read in the newspaper today about some Northern Telecom fibre-optic equipment that uses a signalling technology called SONET. Does anybody know what SONET actually is?
elliott@ames.arc.nasa.gov (Paul Elliott x225) (10/16/89)
In article <telecom-v09i0447m05@vector.dallas.tx.us>, gamiddleton@watmath. waterloo.edu (Guy Middleton) writes: > I read in the newspaper today about some Northern Telecom fibre-optic > equipment that uses a signalling technology called SONET. Does anybody know > what SONET actually is? SONET is an acronym for Synchronous Optical NETwork. It is not really a signaling technology, but rather is the North American fiber optic transmission standard. The SONET standard is described in Bellcore TA-TSY-000253 (Issue 3, July 1988). SONET transports telephony signals as payloads of multiple DS0 (Dee-Ess-Zero) channels, each DS0 being 64 Kbit/s arranged as 8 bits/channel with an 8000 Hz channel repetition rate. 24 channels are grouped (with one frame bit) into a frame; the resulting signal is called a DS1, and is the basic T1 signal. I won't go into the various signaling and framing formats here (unless someone really twists my arm). SONET provides for several optical transmission rates; these are: STS-1, OC-1: 51.840 Mbit/s, 672 DS0 channels STS-3, OC-3: 155.52 Mbit/s, 3x OC-1 ... and on, up to: STS-48, OC-48: 2488.32 Mbit/s, 48x OC-1 (STS-N = Synchronous Transport Signal level N, the signal description) (OC-N = Optical Carrier level N, the STS-N after conversion to light) Note that the data rates above do not correspond exactly to the number of DS-0 channels being transported. This is due to additional overhead data in the SONET signal. The SONET signal uses laser light sources and single-mode fiber. Here at Optilink, we were amused to see the Northern Telecom press release (in which they claimed to be the first), as we have had a SONET digital loop carrier system in field-trials at several sites for a few months now. The article in the paper was a bit sketchy, so perhaps they are indeed first at _something_SONET_, but certainly they are not alone in the field. Paul M. Elliott Optilink Corporation (707) 795-9444 {pyramid,pixar,tekbspa}!optilink!elliott "I used to think I was indecisive, but now I'm not so sure."
tad@beaver.cs.washington.edu (10/19/89)
Seriously....I always thought SONET referred to Southern New England Telephone Co! Tad Cook tad@ssc.UUCP
johnl@esegue.segue.boston.ma.us (John R. Levine) (10/20/89)
In article <telecom-v09i0461m08@vector.dallas.tx.us> amc-gw!ssc!tad@beaver.cs. washington.edu writes: >Seriously....I always thought SONET referred to Southern New England >Telephone Co! No, that's SNET, pronounced snet, or perhaps SNET Co., pronounced snetco. When I lived in New Haven, all sorts of events happened at the SNET Co. auditorium. Since SNET was an AT&T affiliate rather than a subsidiary, they are not subject to all the restrictions on the RBOCs and they set up a subsidiary sonorously named Sonecor which attempts without notable success to make big bucks in unregulated businesses. SNET lives in my memory as the only phone company ever to send me a "pay or we'll turn off your phone" letter before they even sent the bill. John R. Levine, Segue Software, POB 349, Cambridge MA 02238, +1 617 864 9650 johnl@esegue.segue.boston.ma.us, {ima|lotus|spdcc}!esegue!johnl Massachusetts has over 100,000 unlicensed drivers. -The Globe [Moderator's Note: I might add that SNET Financial Services, Inc. is a big lender of money for people who buy computer systems. In my real life work, they are a client of ours. They lend *huge* amounts of money to commercial borrowers, and function as a factor for computer brokers. PT]
hui@joplin.mpr.ca (Michael Hui) (10/23/89)
I was on the hardware design team of NT's new SONET product line. I designed two ASICs for that product, both involved intimately with the SONET protocol. Currently I am _not_ with Bell-Northern Research anymore. BNR was the R&D arm of NT that actually did the product development. In order to keep myself out of hot water, please only ask (if you want) questions of a nonproprietary nature. This much I will share with you all: The NT offering implements nearly EVERYTHING in the SONET standard. It is very unlikely that it won't be able to work with any other manufacturer's equipment. Yes, it was designed by a very competent team of engineers. It's also very unlikely that we have overlooked subtleties in the standard. The system was subject to extensive chip level, multi-chip level, system level simulation, using our mainframes and Zycad hardware simulation engine. There were still changes to the standard during our development time frame. Most of those have been incorporated into the hardware. The inclination is strong at this point for other telecom engineers to come on stream and debat how/whether/what parts of the standard we implemented. Please keep in mind the proprietary nature of your company's projects, as well as my former employer's rights to their trade secrets. If you really want to know the whole story, please apply for a job in the SONET development group at BNR. It's a good company to work for. I heartily recommend it. Now, if only I could get my hands on the silly sales brochure ...
tad@ssc.UUCP (Tad Cook) (10/23/89)
In article <telecom-v09i0461m08@vector.dallas.tx.us>, amc-gw!ssc!tad@beaver. cs.washington.edu writes: > Seriously....I always thought SONET referred to Southern New England > Telephone Co! OOPS! I just realized that I must have been thinking of SNET, and entirely different animal, of course! Never mind. Tad Cook Seattle, WA Tad@ssc.UUCP MCI Mail: 3288544
elliott@ames.arc.nasa.gov (Paul Elliott x225) (10/25/89)
In article <telecom-v09i0469m03@vector.dallas.tx.us>, hui@joplin.mpr.ca (Michael Hui) writes: > .... > The NT offering implements nearly EVERYTHING in the SONET standard. It > is very unlikely that it won't be able to work with any other > manufacturer's equipment. > .... > The inclination is strong at this point for other telecom engineers to > come on stream and debate how/whether/what parts of the standard we > implemented. > .... In my posting answering (some of) the SONET questions, I mentioned my "amusement" at the NT press release (or used words to that effect). I don't know if Michael is referring to my posting here, but if so, I never intended to imply that NT's implementation was anything but superb. Actually, I have no info on the NT design other than the few paragraphs I saw in the newspaper. ... I just re-read my original post, and find that I used the phrase "_something_SONET_", and this looks suspiciously like what his comments were referring to. What I meant was that the transport of SONET requires many pieces of equipment at various places in the network, and that the NT product may be the first in it's area, but was not the first SONET equipment to hit the field. I did not intend to imply that it only implemented a subset of SONET or anything like that. Anyway, enough humble apology from me for now. On the other hand, if this wasn't referring to my posting....never mind. Paul M. Elliott Optilink Corporation (707) 795-9444 {pyramid,pixar,tekbspa}!optilink!elliott "I used to think I was indecisive, but now I'm not so sure."