The Future of Service Providers


Remote access design is usually implemented to meet the business need for a longer rather than shorter period. This decision requires an answer to the question "how will service providers change in the future?" Emerging technologies will continue to require that enhanced and complex services be supported by providers.

Service Offering

One of the main directions in the service offering for remote access is Multiprotocol Label Switching VPN (RA to MPLS VPN). This service enables users to connect to the corporate network and handles remote access connectivity for mobile users, telecommuters, and small offices through dial, ISDN, DSL, cable, and wireless technologies (see more in Chapter 19). The increase of IP-based transport changes the focus of the transport from TDM to packet-based services. The connection-oriented restrictions of TDM systems will be overcome with connectionless technologies by providing higher versatility and multiservice support features. These technologies include Media Gateway Control Protocol (MGCP), HTML, Voice XML (VXML), session initiation protocol (SIP), and Automatic Speech Recognition (ASR). These technologies enable service offerings that can be tailored to any combination to meet the customer's needs.

The Last-Mile Problem

In July 2001, a group called IEEE 802.3ah Ethernet in the First Mile Task Force (http://grouper.ieee.org/groups/802/3/efm/public/) was established to provide solutions for the so-called last-mile issue. Currently, a wide variety of protocols provide services to the last mile. They include ISDN, DSL, cable modems, satellite, and broadband wireless solutions, which offer speeds under 10 Mbps. However, existing Intranets use technologies such as Fast and Giga-Ethernet with speeds several Gbps and higher. Therefore, to interconnect these two environments, a fairly sophisticated protocol conversion is required.

To achieve the conversion goal, the Task Force planned to bring Ethernet to home users. For this purpose, IEEE 803.3ah defines three access layers : home network, access/distribution layer, and a core layer. IEEE also defines three main topologies (the analogy with the Cisco design model is obvious). [1] The topologies are based on two main factors for media and for configuration of the access/distribution layer:

  • Ethernet over a point-to-point copper line is expected to adopt the very-high-data-rate DSL (VDSL) and Media Access Control (MAC) protocol on the top of the VDSL physical specification. This should be able to deliver speeds ranging from 10 Mbps and higher over existing copper cabling.

  • Gigabit Ethernet over point-to-point fiber is supposed to deliver speeds up to 1 Gbps for distances up to 10 km (6.25 miles).

  • Point-to-multipoint fiber topologyThe multipoint part is an aggregation point, called an access switch, which provides services for up to 16 passive splitters that are connected to optical network terminators. This topology is designed to deliver speeds starting from 30 to 60 Mbps, up to 100 to 200 Mbps for business and residential customers.

Cisco Systems announced the Optical Ethernet to the First Mile (EFM) Cisco Catalyst 4000 Family in December 2001. The Cisco Catalyst 4000 Series includes a 48-Port 1000BASE-LX Gigabit Ethernet Line Card, a 48-Port 100Base-FX Line Card and a Cisco ONT 1000 Gigabit Ethernet. All solutions work with the Cisco Ethernet Subscriber Solution Engine 1105 (Cisco ESSE 1105), which is a hardware-based management system for metro access networks and the Cisco Secure Access Control Server (ACS) Version 3.0 centralized access control.

The 3G Wireless Alternative

A bit of a battle is shaping up inside the industry over 2G, 2.5G, and 2.75G solutions. Verizon and Sprint are backing (code division multiple access) CDMA2000 technology. AT&T Wireless, Cingular Wireless, and VoiceStream are backing the Global System of Mobility/General Packet Radio Service (GSM/GPRS) systems, which provide speeds that range from 15 to 40 kbps. Nextel is backing its iDEN (Motorola proprietary version of TDMA with its unique push-to-talk radio capability).

The Wireless 3-th Generation (3G) solution is seen as an evolutionary new path in telecommunications. CDMA2000 1xEV-DO was standardized by the Telecommunications Industry Association (TIA) in October 2000. 1xEV-DO was recognized by the ITU-R WP8F as an IMT-2000 standard.

The first CDMA2000 networks were launched in Korea in October 2000, providing 144-kbps data rates to subscribing customers and delivering nearly twice the voice capacity that operators experienced with their cdmaOne (IS-95) systems. The success of the CDMA2000 1X system in Korea has encouraged many operators in the Americas and Asia to follow through with their plans to launch CDMA2000 this year.

Although the arguments about true 3G solutions in the U.S. are underway, Verizon Wireless with its Express Networks became the first carrier to launch 3G wireless in the U.S. in January 2002primarily in the Bay Area, East Coast, and Salt Lake Cityoffering speeds up to 144 kbps, with an average of 40-60 kbps. Meanwhile, Sprint PSC, working with partners such as Samsung and Hitachi, announced its plans and launched nationwide (U.S. market), a 3G solution in August 2002 called PCS Vision.

According to the ITU, a 3G link must be able to send data at rates of up to 144 kbps while mobile, at rates of up to 384 kbps at walking speeds, and at rates of up to 2.4 Mbps when stationary. These speeds are expected to be exceeded soon. The available sources show that plans are underway for variations on CDMA2000, which will change 3G systems dramatically. The wider band , commonly referred to as CDMA2000 3X or 3XRTT will be replaced by a two-phase strategy called CDMA2000 1xEV. 1xEV stands for 1X evolution, or evolution using 1.25 MHz, which is typical for today's CDMA2000 1X systems based on a standard 1.25 MHz carrier for delivering high data rates and increased voice capacity peak data rates of 2.4 Mbps. The 1xEV includes two phases, labeled 1xEV-DO (DO-data only) and 1xEV-DV (DV-data and voice). The CDMA2000 1xEV-DO can provide customers with peak data rates of 2.4 Mbps. However, to implement 1xEV-DO, operators will have to install a separate carrier that's dedicated to data-only use at each cell location where high-speed data services are demanded. Still, customers will be able to hand off seamlessly from a 1X to a 1xEV-DO carrier.

As long as the demand for high-speed wireless high-speed access grows in the years ahead, all the carriers are expected to upgrade their systems to provide 3G services.

E-mail exchange, instant messaging, and Internet browsing are the major forces behind the demand for 3G services.




Troubleshooting Remote Access Networks CCIE Professional Development
Troubleshooting Remote Access Networks (CCIE Professional Development)
ISBN: 1587050765
EAN: 2147483647
Year: 2002
Pages: 235

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