b Physical Network Design Muhammad Anshari Selecting Technologies and Devices for Networks

Selecting Technologies and Devices LAN Cabling Plant Design LAN Technologies Selecting Internetworking Devices

Intro Physical network design involves the selection of LAN and WAN technologi. During this phase of the top-down network design process, choices are made regarding cabling, physical and data link layer protocols, and internetworking devices (such as hubs, switches, routers, and wireless access points). es for campus and enterprise network designs. A network designer has many options for LAN and WAN implementations. No single technology or device is the right answer for all circumstances.

a. LAN Cabling Plant Design Topologi Kabel; –A centralized cabling scheme terminates most or all of the cable runs in one area of the design environment. A star topology is an example of a centralized system. –A distributed cabling scheme terminates cable runs throughout the design environment. Ring, bus, and tree topologies are examples of distributed systems. Building-Cabling Topologies; Within a building, either a centralized or distributed architecture can be used, depending on the size of the building. For small buildings, a centralized scheme with all cables terminating in a communications room on one floor is possible. A centralized scheme offers good manageability but does not scale. For larger buildings, a distributed topology is more appropriate. Many LAN technologies make an assumption that workstations are no more than 100 meters from a telecommunications closet where hubs or switches reside. For this reason, in a tall building with large floors, a distributed topology is more appropriate

LAN Cabling Plant Design Campus-Cabling Topologies; The cabling that connects buildings is exposed to more physical hazards than the cabling within buildings. A distributed scheme offers better availability than a centralized scheme. The top part of Figure 10-2 shows a centralized topology. The bottom part of Figure 10-2 shows a distributed topology. The centralized topology in Figure 10-2 would experience a loss of all interbuilding communication if the cable bundle between Buildings A and B were cut. With the distributed topology, interbuilding communication could resume if a cable cut between Buildings A and B occurred.Figure 10-2

Jenis Kabel Three major types of cables are used in campus network implementations: –Shielded copper, including shielded twisted-pair (STP), coaxial (coax), and twin-axial (twinax) cables –Unshielded copper (typically UTP) cables –Fiber-optic cables STP cabling was widely used in Token Ring networks in the 1980s and 1990s. Most Token Ring networks have been replaced by Ethernet networks these days. Ethernet generally uses UTP and fiber-optic cabl. Coax cable was popular in the early days of LANs.ing, although it is possible to make Ethernet work on STP cabling. The cabling was usually installed in a bus topology and was hard to manage in large installations without multiport repeaters. UTP is the typical wiring found in most buildings these days. It is generally the least expensive of the three types of cables. It also has the lowest transmission capabilities because it is subject to cross talk, noise, and electromagnetic interference. Fiber-optic cables are quickly becoming a standard for new facilities. As the prices for cables and connection devices drop, it becomes practical to install fiber-optic cabling for vertical and horizontal wiring between telecommunications closets. Some companies also use fiber-optic cabling for work-area wiring, but the cost of network interface cards (NICs) with fiber-optic support is still high, so that is not common yet. Fiber-optic cabling has been used between buildings for many years.

LAN Teknologi This section covers data link layer technologies that are available for LANs. Ethernet is recommended for most campus networks because it provides superior scalability, manageability, and affordability. ATM is also scalable, but it is more complex and expensive than Ethernet and harder to configure and manage.

Selecting Internetworking Devices for a Campus Network Design

Latihan Sebagai network admin, anda diinformasikan oleh manajer bahwa perusahaan anda akan dikembangkan dan pindah ke gedung baru. Anda diberi informasi oleh pemilik gedung bahwa semua lantai bangunan tersebut telah dipasangi kabel dengan Cat-5 UTP. Anda diminta untuk memberikan rekomendasi jaringan yang handal, murah, yang mudah untuk dikembangkan lebih lanjut untuk kebutuhan kedepan. Kecepatan tinggi sangat diharapkan tapi biaya menjadi faktor utama. Jenis network apa yang akan anda rekomendasi?

Rekomendasi Rekomendasi anda adalah 100BaseTX(fast ethernet) adalah pilihan yang tepat. Fast ethernet menggunakan Cat-5 UTP dan yang paling populer saat ini. Karena gedung sudah diinstall dengan kabel tersebut maka hanya diperlukan perlengkapan jaringan lain perlu dibeli. Lebih lanjut Fast Ethernet sangat memungkinkan untuk future growth