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Technology Stocks : LAST MILE TECHNOLOGIES - Let's Discuss Them Here -- Ignore unavailable to you. Want to Upgrade?

To: MikeM54321 who wrote (1857)	8/7/1998 7:11:00 PM
From: DenverTechie	Respond to of 12823

MikeM you are correct that Fore's ATM switch was not purpose built for HFC. However, they are one of the leaders in the enterprise size ATM market and the sizing and port capacities of the Fore switch matched up the best with RoadRunner's needs. Time Warner Cable's first foray into ATM was with the Lucent Globespan 2000 for the Full Service Network in Orlando for delivering interactive multimedia including video on demand. It was not purpose built either since cable wants to use off the shelf (however bleeding edge at the time) gear whenever possible for interoperability with other equipment in the network and also not the least to keep costs down Tellabs is one of the leaders in the voice over HFC market (along with Nortel's Arris Interactive joint venture), but you don't hear much about them. They have an excellent architecture and good cost structure for less dense network areas. They have major contracts with all the major cable companies providing this service. They have also penetrated the European voice over HFC market in a big way. The Stratus computers will fit in the HFC environment. The way to get full functionality for IP telephony is to have SS7 support and other operational support systems that make IP telephony look as close to circuit switched telephony as possible. Stratus systems will enable this over HFC as over any other network using IP for voice services. But critical in the case of HFC cable based networks because the is no existing support infrastructure in place as there is for other networks.

To: MikeM54321 who wrote (1857)	8/7/1998 8:53:00 PM
From: Hiram Walker	Respond to of 12823

Mike, a great article from IBM et all, HLIT works with them over in Israel. Anyway it addresses my contention at to how to implement the future technologies for last mile. bcr.com In the SONET multiplexing structure, high-speed signals can be created in two ways. As shown in Figure 2, a number of discrete STS-1 channels, each with its own payload and overhead, can be multiplexed together. SONET also defines concatenated formats where the payloads from several STS-1 equivalents are combined to create one higher-capacity channel. The concatenated formats are identified by the suffix "c," and the STS-3c and STS-12c formats are currently defined as transport options for ATM and other network services. Now, in addition to these two possibilities, DWDM provides an additional multiplexing option: Several optical signals can be combined onto the same fiber path. Because WDM operates at the optical range, it couldn't care less about the digital multiplexing format that is being used. That means SONET and non-SONET fiber systems, as well as analog fiber systems used for cable television, can all be combined onto the same fiber New Switching Options Clearly what we are getting here is a whole new set of options for how to switch, multiplex and transmit information in a high-capacity network (Figure 4, p. 26). By itself, SONET was a major step in building flexibility and functionality into a fiber network. The SONET terminal is the main serving device for lower-capacity channels; SONET add/drop muxes allow the carrier to reconfigure channels at Layer 1 (i.e., digital cross connect), using commands sent in part of the SONET overhead. If the system used virtual tributary mapping, the SONET device could cross-connect individual DS1 channels. If the interface to the SONET environment were an asynchronous DS3 (i.e., the output of an M13 multiplexer), the SONET network could only cross-connect the entire DS3. The development of DWDM and high-capacity ATM and Layer 3 switches will provide new options for how switched or dedicated services can be delivered to users. With DWDM, each independent fiber transmitter is assigned a different wavelength, which means we can switch different wavelengths onto different paths. The ability to switch those different wavelengths is called lambda switching or photonic switching. (If SONET is doing Layer 1 switching, lambda switching must be Layer 0.5!) The idea in a photonic switch would be to use a switching network to break out the wavelengths of the various fiber inputs and recombine them into new outputs. The first step toward photonic switching--optical cross connects and add/drop multiplexers--is no longer a distant prospect. Ciena Corp. (www.ciena.com) and Harmonic Lightwaves are developing products for rearranging optical channels. Lucent (www.lucent.com) introduced a preliminary 32-line optical cross connect system last year. Others, like Astarte Fiber Networks (www.starswitch.com) and Cambrian Systems (www.cambriansys.com, a division of Newbridge) are also planning products in this area. Chorum Technologies (www.chorumtech.com) and Tellium (www.tellium.com) are developing optical add/drop multiplexers for WDM fiber networks. Other suppliers, like Lightwave Microsystems (www.lightwavemicro.com) and Optical Micromachines (San Diego) are building components for switching optical signals. The preliminary versions of these devices are quite costly, but according to Mr. Levi of Harmonic Lightwaves, photonic switches should be readily available and cost effective in two to five years. While lambda switching gives us a Layer 0.5 switching capability, ATM switches and Layer 3 switches give us Layer 2 and Layer 3 capabilities. If you have been following recent announcements from established companies like Bay and Cisco, as well as upstarts like Avici Systems and Juniper Networks (see BCR, May 1998, pp. 56-59), you know that router capacities are exploding. One of the great surprises in network technology in the past few years is that we can do hardware switching without ATM. While many of the Layer 3 switching devices actually use ATM under IP (i.e., the IP datagram is split up into a series of 48-octet chunks and sent on an ATM virtual circuit), others like Avici are looking at switching IP directly, without depending on ATM. In either case, SONET will define the standard Layer 1 trunk format, and the SONET frame will be filled with either ATM cells or IP datagrams. If we can build that SONET interface directly into the ATM or Layer 3 switch, it could produce traffic that is wrapped and ready for SONET and connects directly to DWDM equipment. In fact, Ascend Communications and Williams Communications recently announced plans for just such a new network infrastructure. What all of this means is our switching options are sliding all over the OSI model. Given their capacities, ATM and IP switching devices have been designed to deliver end user services. If we have an ATM or Layer 3 switch with sufficient capacity, we might be able to eliminate digital cross-connects. We are already starting to see this "layer creep" in campus networks, where Layer 3 switches are reaching the same price/performance point as Layer 2 LAN switches. Why bother cross-connecting Layer 1 pipes when it's just as cheap to handle all the information on a cell or datagram basis? Hiram

To: MikeM54321 who wrote (1857)	8/8/1998 12:48:00 PM
From: Frank A. Coluccio	Read Replies (2) \| Respond to of 12823

Mike, From my viewpoint, we're not looking at a monolithic set of changes or migrations in the cable industry, as would be characterized by lock step migrations. Rather, the industry is still very fragmented and we're witnessing many different directions of change within the same industry. HFC, however, seems to have finally taken hold and while each operator or MSO may elect to configure its own internal core network and distribution lines differently, they will still be bound by a universally relevant set of attributes and interfaces, since they must all hand off traffic from one to the other, and to the greater global network. And the latter, itself, is undergoing changes at the same time. >>But don't forget, any networking ATM switching equipment could have been used instead of Fore's. I don't believe Fore's ATM switching equipment was purpose-built for HFC. Also Tellabs does have voice over cable expertise. And remember Ascend bought Stratus (SS7 telecom support) lately. How this integrates into an HFC solution, I'm not sure? But I think it does. Maybe DenverTechie or Frank knows? << You've made several points. In some ways, cable operators' head ends will resemble ISP POP server farms as newer services get unpacked and ready for delivery. In those situations where the operator will continue to force feed switched services over DSOs over spectrum using classical FDM and OFDM, they will resemble the telco end office switch locations we have all become familiar with. But in a very short time frame, I think that these operators will live to regret that selection of investment, since the fast emerging IP alternatives will permit a faster ramp-up to application level convergence at the protocol [namely IP] level. ATM is not an inhibitor in this sense, since it is poised to support IP as well. But it does add another level of infrastructure and complexity which is increasingly falling out of favor with architects, albeit of the bleeding edge variety, as optical solutions begin to unfold, and as higher capacities of bandwidth become available through DWDM and optical switching & routing techniques. I suppose the benefits and the costs associated with ATM in FTTC architectures need to be examined on a case by case basis, still, since time to market is a factor and some of the emerging techs which are still just over the horizon are not ready for prime time, and may not be for another two or three years in a way that will scale well in existing subscriber networks. Backwards compatibility is a bummer in this regard, requiring dual operations platforms to be maintained, and most operators are not up to this without massive capital infusions to handle the costs. This presents grounds for argument in favor of the clout that T affords in the TCOMA situation. Getting back to ATM, if it is embedded in the core of a network, and extended out to the neighborhoods, then it's almost a no brainer that it will be used to the premises as well [in the case of the FSAN and other FTTC architectures such as BroadBand Technologies and Next Level]. Despite the conventional wisdom associated with this tact, there will always be newer alternatives becoming available, and that means that the ATM solution may well be relegated, in record time, to legacy status against which new forms of optimization may be motivated. Very Fast IP flows come to mind, for not only voice and data, but for video as well over time. This will require price points for routing to come down further, but isn't that a common factor that has to be taken into account? I am encouraged to read that some emergent companies are beginning to focus on optical level routing. One such company is talking about "bar coding" optically based streams over discrete wavelengths for this purpose. It's going to happen sooner than we'd commonly think. Unless, of course, the rush into now-current techs forces another five to ten year depreciation lock on progress. It happens. I'm not specifically aware of any direct involvement between SRA and cable telephony, although those technologies are being ported by others as we speak, and I see no barrier to ASND's ability to do the same. But a quick glance at the ASND web site reveals that they have been primarily, up until now, devoted to the traditional carrier model in this regard. From their web page that describes their multi voice strategy ascend.com , I offer: ---- Introduction Ascend MultiVoice Transparent Connectivity Access Port Diversity Exploiting the Power of Ascend Switches Three-phase MultiVoice Roll Out Phase One-MultiVoice for IP and Frame Relay Phase Two-MultiVoice over ATM Phase Three-MultiVoice Platform ---- That's not to suggest that they don't have something on the burner ready, for release tomorrow, however. Regards, Frank C.