Lecture CCNA Exploration 4.0 (Kỳ 4) - Chapter 6: Teleworker services

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Describe the enterprise requirements for providing teleworker services, including the differences between private and public network infrastructures. Describe the teleworker requirements and recommended architecture for providing teleworking services. Explain how broadband services extend enterprise networks using DSL, cable, and wireless technology,...

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Nội dung Text: Lecture CCNA Exploration 4.0 (Kỳ 4) - Chapter 6: Teleworker services

Chapter 6 - Teleworker Services CCNA Exploration 4.0 1
Introduction Học viện mạng Bach Khoa - Website: www.bkacad.com 2
Business Requirements for Teleworker Services Học viện mạng Bach Khoa - Website: www.bkacad.com 3
The Business Requirements for Teleworker Services • When designing network architectures that support a teleworking solution, designers must balance organizational requirements for security, infrastructure management, scalability, and affordability against the practical needs of teleworkers for ease of use, connection speeds, and reliability of service. Học viện mạng Bach Khoa - Website: www.bkacad.com 4
The Teleworker Solution • The term broadband refers to advanced communications systems capable of providing high-speed transmission of services, such as data, voice, and video, over the Internet and other networks. • Transmission is provided by a wide range of technologies, including digital subscriber line (DSL) and fiber-optic cable, coaxial cable, wireless technology, and satellite. Học viện mạng Bach Khoa - Website: www.bkacad.com 5
The Teleworker Solution • Soon, voice over IP (VoIP) and videoconferencing components will become expected parts of the teleworkers toolkit. • Home Office Components - The required home office components are a laptop or desktop computer, broadband access (cable or DSL), and a VPN router or VPN client software installed on the computer. Additional components might include a wireless access point. When traveling, teleworkers need an Internet connection and a VPN client to connect to the corporate network over any available dialup, network, or broadband connection. • Corporate Components - Corporate components are VPN-capable routers, VPN concentrators, multifunction security appliances, authentication, and central management devices for resilient aggregation and termination of the VPN connections. Học viện mạng Bach Khoa - Website: www.bkacad.com 6
Broadband Services Học viện mạng Bach Khoa - Website: www.bkacad.com 7
Connecting Teleworkers to the WAN • The choice of access network technology and the need to ensure suitable bandwidth are the first considerations to address when connecting teleworkers. Học viện mạng Bach Khoa - Website: www.bkacad.com 8
Connecting Teleworkers to the WAN Học viện mạng Bach Khoa - Website: www.bkacad.com 9
Cable Học viện mạng Bach Khoa - Website: www.bkacad.com 10
Cable Học viện mạng Bach Khoa - Website: www.bkacad.com 11
Cable Học viện mạng Bach Khoa - Website: www.bkacad.com 12
Cable • The Data-over-Cable Service Interface Specification (DOCSIS) is an international standard developed by CableLabs, a non-profit research and development consortium for cable-related technologies. • DOCSIS specifies the OSI Layer 1 and Layer 2 requirements: – Physical layer - For data signals that the cable operator can use, DOCSIS specifies the channel widths (bandwidths of each channel) as 200 kHz, 400 kHz, 800 kHz, 1.6 MHz, 3.2 MHz, and 6.4 MHz. DOCSIS also specifies modulation techniques (the way to use the RF signal to convey digital data). – MAC layer - Defines a deterministic access method, time-division multiple access (TDMA) or synchronous code division multiple access method (S-CDMA). Học viện mạng Bach Khoa - Website: www.bkacad.com 13
Cable Học viện mạng Bach Khoa - Website: www.bkacad.com 14
Học viện mạng Bach Khoa - Website: www.bkacad.com 15
DSL • DSL is a means of providing high-speed connections over installed copper wires. • Several years ago, Bell Labs identified that a typical voice conversation over a local loop only required bandwidth of 300 Hz to 3 kHz. • Advances in technology allowed DSL to use the additional bandwidth from 3 kHz up to 1 MHz to deliver high-speed data services over ordinary copper lines. • The two basic types of DSL technologies are asymmetric (ADSL) and symmetric (SDSL). • The transfer rates are dependent on the actual length of the local loop, and the type and condition of its cabling. For satisfactory service, the loop must be less than 5.5 kilometers (3.5 miles). Học viện mạng Bach Khoa - Website: www.bkacad.com 16
DSL • The two key components are the DSL transceiver and the DSLAM: – Transceiver - Connects the computer of the teleworker to the DSL. Usually the transceiver is a DSL modem connected to the computer using a USB or Ethernet cable. Newer DSL transceivers can be built into small routers with multiple 10/100 switch ports suitable for home office use. – DSLAM - Located at the CO of the carrier, the DSLAM combines individual DSL connections from users into one high-capacity link to an ISP, and thereby, to the Internet. Học viện mạng Bach Khoa - Website: www.bkacad.com 17
DSL • The major benefit of ADSL is the ability to provide data services along with POTS voice services. • ADSL signals distort voice transmission and are split or filtered at the customer premises. There are two ways to separate ADSL from voice at the customer premises: using a microfilter or using a splitter. Học viện mạng Bach Khoa - Website: www.bkacad.com 18
DSL • A microfilter is a passive low-pass filter with two ends. One end connects to the telephone, and the other end connects to the telephone wall jack. This solution eliminates the need for a technician to visit the premises and allows the user to use any jack in the house for voice or ADSL service. Học viện mạng Bach Khoa - Website: www.bkacad.com 19
DSL • POTS splitters separate the DSL traffic from the POTS traffic. The POTS splitter is a passive device. In the event of a power failure, the voice traffic still travels to the voice switch in the CO of the carrier. • Splitters are located at the CO and, in some deployments, at the customer premises. At the CO, the POTS splitter separates the voice traffic, destined for POTS connections, and the data traffic destined for the DSLAM. Học viện mạng Bach Khoa - Website: www.bkacad.com 20