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The Line Interface Unit provides signal conditioning. The ADSL modem, besides up/down converting the signal to/from the analog signal with the desired bandwidth, converts the ATM cell stream to/from the non-native bit stream. The non-native bit streams include POTS, video, audio, multimedia, and Internet access applications.
Network management requires the service provider to poll the ATM switch, both backbone and edge switches. The service provider reads the switch MIB variables of interest periodically. Typical reporting periods are 30-minute intervals with some providers moving toward a 15-minute interval in 1998. Trunk and edge access utilization are monitored for service engineering design compliance to ensure QoS class objectives are achieved. Cell loss, peak and average cell times, PVC, and port utilization are some of the network variables that are monitored. Since the data is removed from the switch every 30 minutes, all values are an average of the previous 30-minute time period. Therefore, a user can regularly burst above their PCR without incurring any additional cost, as long as the average PCR over the measurement interval is below the negotiated PCR rate.
Some service providers offer online reports accessible by users for network monitoring. These reports are available for selected time periods, in the measurement increments of 15 or 30 minutes, of hourly, daily, weekly, and monthly. The online port and PVC statistics do not match the billing statistics the user receives due to different business reporting systems utilized for network monitoring and billing.
PVC test loops trace every path in the network. These loops are used to measure loss, delay, and delay variation. Currently, typical network availability is around 99.95 percent.
A 99.95 percent network availability means the network is not available to the user for 36 minutes during a 31-day month.
ATM Interworking is also called Multiple Services Platform (MSP). ATM Interworking provides the ability to pass traffic originating from sources utilizing other protocols across the ATM network. The source data, called non-native since in its original format it is not ATM, must first be converted to the ATM protocol format before it can transit the ATM network. Customer premises equipment called aggregators or concentrators can perform the conversion to ATM protocol.
After the non-native data is converted to ATM format it can be transmitted to any destination regardless of the native protocol of the destination as long as an aggregator or concentrator reformats the data in the native protocol if it is not ATM.
As an example, a Frame Relay concentrator can convert the frames to cells and ship them across the ATM network to an SMDS destination (Switched Multimegabit Data Service), as long as the SMDS destination has an ATM-to-SMDS concentrator to reformat the ATM cells. Also, for Frame Relay interworking, frame PVCs can be carried over ATM PVCs. Or, frame PVCs can be multiplexed onto one ATM PVC.
There exist in the "clouds" many communication technologies, some with great similarity and many with great disparities between their protocols and technologies. There also exist in the "clouds" many user networks utilizing the diverse protocols and technologies seeking to connect to not so similar networks and finding that it can be an acrimonious, complicated, and expensive proposition that can yield a marriage between technologies made in hell. ATM Interworking is the magic that makes the marriage between diverse networks a marriage not made in the "clouds" but one made in the heavens. ATM Interworking provides several benefits worth noting here.
With customer premises concentrators and aggregators providing the ATM-to-whatever interface, ATM Interworking provides a seamless, global data, video, and voice service. CPE is available now that can provide interworking for several legacy technologies. And the CPE is not expensive. Original equipment manufacturers (OEMs) plan to introduce new concentrators and aggregators for the technologies and protocols that are not yet able to be converted by the end of 1998.
ATM Interworking provides users with a smooth, quick, and very economical migration path to ATM. ATM Interworking is as easy as it gets in the networking business. Just purchase, install, turn on, and configure the CPE concentrator or aggregator. Now, you have global access to any other network connected to ATM. ATM Interworking quickly extends the LAN (LAN Extension, or LANE), giving access to WANs and GANs. The day of plug-and-play internetworking is not far off.
ATM Interworking is not without some challenges. Extending LANs to WANs and GANs creates a significant network management issue. To cope with the countrywide, continental, and global management issues, service providers are turning up network management services that not only manage the provider’s backbone network but can also manage the customer premises. While the service providers are struggling to define who, what, when, why, where, and how, entrepreneurial third-party vendors are stepping into the vacuum and offering complete network management services, including site preparation, purchasing, installing, and maintaining CPE, and providing around the clock network monitoring. Additionally, these creative companies can provide any number of network usage and status reports online for the customer.
IP traffic is already heavily multiplexed, which makes ATM overhead a more noticeable burden. Demultiplexing IP traffic may be a short-term solution; changing to native ATM as equipment and systems age is a viable long-term solution.
Service Level Guarantees (SLGs) for Frame Relay is stated contractually in terms of frames. Service Level Guarantees for ATM are stated in terms of cells. Usually, there is not a one-to-one correspondence between the contents of a Frame Relay frame and the contents of an ATM cell. Service providers must determine how to interpret SLGs for ATM Interworking network topologies.
A robust ATM Interworking solution supports all transmission technologies including SMDS, Frame Relay, X.25, IP, audio, voice and video. Currently, ATM Interworking does not support SMDS and X.25 data technologies. Voice Over ATM (VOA) is available from several service providers that use equipment supplied from OEMs each using proprietary solutions. Until the ATM Forum completes the VOA specification and the subsequent adoption of the specification by the industry, the proprietary nature of current solutions makes VOA interworking problematic. The ATM Forum expects to complete a VOA specification by the end of 1998. Vendor compliant equipment will follow soon afterwards.
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