This chapter from Cisco Press offers an overview from the technologies available today to style networks. Discussions are divided into designing campus networks, designing WANs, utilizing remote connection design, delivering integrated solutions, and figuring out networking requirements.
Networkingthe communication among two or far more networksencompasses just about every aspect of connecting computers together. Networks have grown to help vastly disparate end-system communication specifications. A network demands quite a few protocols and functions to permit scalability and manageability devoid of continuous manual intervention. Massive networks can consist in the following 3 distinct elements:
Campus networks, which consist of locally connected users within a making or group of buildings
Wide-area networks (WANs), which connect campuses
Remote connections, which link branch offices and single users (mobile users and telecommuters) to a nearby campus or the internet
Figure 1-1 delivers an instance of a typical enterprise network.
Figure 1-1 Example of a Typical Enterprise Network
Designing a network could be a challenging task. To style trustworthy, scalable networks, network designers ought to realize that each of the three significant components of a network has distinct design requirements. A network that consists of only 50 meshed routing nodes can pose complicated complications that bring about unpredictable results. Attempting to optimize networks that function a large number of nodes can pose even more complicated troubles.
Regardless of improvements in gear efficiency and media capabilities, network design is becoming more tricky. The trend is toward increasingly complex environments involving numerous media, various protocols, and interconnection to networks outside any single organization's dominion of control. Cautiously designing networks can lower the hardships linked with growth as a networking environment evolves.
This chapter delivers an overview with the technologies out there these days to design networks. Discussions are divided in to the following general topics:
Designing campus networks
Designing WANs
Utilizing remote connection style
Supplying integrated options
Determining your networking requirements
Designing Campus Networks
A campus network is actually a making or group of buildings all connected into one enterprise network that consists of many local-area networks (LANs). A campus is generally a portion of a corporation (or the entire organization) that is constrained to a fixed geographic region, as shown in Figure 1-2.
The distinct characteristic of a campus atmosphere is that the firm that owns the campus network in most cases owns the physical wires deployed inside the campus. The campus network topology is primarily LAN engineering connecting each of the end systems inside the creating. Campus networks generally use LAN technologies, for example Ethernet, Token Ring, Fiber Distributed Data Interface (FDDI), Rapidly Ethernet, Gigabit Ethernet, and Asynchronous Transfer Mode (ATM).
Figure 1-2 Instance of a Campus Network
A large campus with groups of buildings can also use WAN technology to connect the buildings. Although the wiring and protocols of a campus might possibly be according to WAN engineering, they do not share the WAN constraint of the high price of bandwidth. Just after the wire is installed, bandwidth is inexpensive since the company owns the wires and there is no recurring expense to a service provider. Then again, upgrading the physical wiring could be expensive.
Consequently, network designers generally deploy a campus style optimized for the fastest functional architecture that runs on the current physical wire. They may well also upgrade wiring to meet the needs of emerging applications. By way of example, higher-speed technologiessuch as Quickly Ethernet, Gigabit Ethernet, and ATM as a backbone architectureand Layer 2 switching give devoted bandwidth towards the desktop.
Trends in Campus Style
Previously, network designers had only a limited number of hardware optionsrouters or hubswhen buying a technologies for their campus networks. Consequently, it was rare to generate a hardware design mistake. Hubs were for wiring closets, and routers were for the data-center or main telecommunications operations.
Not too long ago, local-area networking has been revolutionized by the exploding use of LAN switching at Layer two (the data link layer) to enhance overall performance and to provide even more bandwidth to meet new information networking applications. LAN switches offer this overall performance benefit by increasing bandwidth and throughput for workgroups and nearby servers. Network designers are deploying LAN switches out toward the network's edge in wiring closets. As Figure 1-3 shows, these switches are usually installed to replace shared concentrator hubs and give higher-bandwidth connections towards the finish user.
Figure 1-3 Example of Trends in Campus Design
Layer three networking is required within the network to interconnect the switched workgroups and to supply solutions that include things like security, good quality of service (QoS), and traffic management. Routing integrates these switched networks, and supplies the safety, stability, and manage necessary to make functional and scalable networks.
Traditionally, Layer two switching has been offered by LAN switches, and Layer three networking has been provided by routers. Increasingly, these two networking functions are getting integrated into widespread platforms. Multilayer switches that provide Layer two and 3 functionality, one example is, are now appearing in the marketplace.
With the advent of such technologies as Layer three switching, LAN switching, and virtual LANs (VLANs), constructing campus networks is becoming significantly more complicated than previously. Table 1-1 summarizes the many LAN technologies expected to develop thriving campus networks. Cisco Systems offers item solutions in all these technologies.
Network designers are now designing campus networks by purchasing separate gear sorts (one example is,cisco certification, routers, Ethernet switches, and ATM switches) and after that linking them. Though person invest in decisions might seem harmless, network designers ought to not forget that this separate gear still works together to type a network.
It really is probable to separate these technologies and make thoughtful styles making use of each and every new engineering, but network designers should give consideration to the overall integration with the network. If this overall integration will not be deemed, the result is usually networks which have a much higher threat of network outages, downtime, and congestion than ever before.
