A Basic Enterprise LAN Network Architecture – Block Diagram and Components

LAN Architecture Diagram and Components
LAN Architecture Diagram and Components

Have you ever wondered about what could be the various networking components that make an enterprise LAN (Computer Network / Local Area Network)? The above diagram shows you the connectivity architecture of the major components that form an enterprise network. We have also included a brief description of the individual components below:

Internet: The Internet cloud refers to the source of the Internet to an organization. The organization could be connected to the Internet via Internet Leased Lines/ Broadband/ 3G etc. For connectivity to other branches, a VPN Network over the Internet could be used (or) A Managed Leased Line/ MPLS circuit could be used as well.

Router: The Enterprise Router is basically a Layer-3 Network device that connects disparate networks. It acts as a gateway between the LAN and the WAN networks and the Internet Leased Lines/ MPLS Circuits/ Managed Leased Lines/ Broadband networks are all terminated on the router. Some Routers support additional modules for secure connectivity to other branches through VPN, Intrusion Prevention and Content Filtering etc. Routers have WAN ports and LAN ports to connect WAN and LAN connections respectively, and some of them have built-in Wireless/ VOIP capabilities.

UTM/ Firewall: The Unified Threat Management Appliance (or software) is for providing gateway level network security for the various end points used in the organization. The UTM Devices provide the following network security options: Firewall, Anti-Spam, Anti-Virus, Content Filtering, URL Filtering, Intrusion Prevention (IPS), Virtual Private Network (VPN), Protection from Internet threats like Phishing etc.

Core Switch: A Core Switch is generally a Layer-3 based Network Switch that connects to the various distribution switches, edge switches (through distribution switches / directly) using Optical Fiber Networks or UTP Copper cabling. They generally also connect to the computer servers (ERP, Web Server, Mail Server, Database Server, Application Servers, etc). The core switch is in the center of an enterprise network and it also provides Inter-VLAN routing. They are either stand-alone switches (24/48 Ports Copper, 4/24 Port Fiber) or Chassis-based where there is processing unit and number of blade modules(For connecting fiber/copper) that go in to empty slots allowing for a flexible configuration.

NAS Device: A NAS Device refers to a Network Area Storage Appliance (This could also be a Storage Area Network, depending upon the storage requirements) where bulk of the files/ data are stored for the servers and individual users (PC’s) to access them over the network whenever required. These appliances are mostly disk based and can be connected anywhere on the network (preferably to a core switch). They come in sizes ranging from 1 TB(Tera Byte) to multiple Tera Byte configurations.

Wireless Controller: There are many access points to provide wireless (Wi-Fi) access to the PC’s/ Laptops/ Wi-Fi Phones in the enterprise. All these Access Points are managed/ controlled by an appliance called ‘Wireless Controller’. Basically a wireless controller provides centralized authentication, encryption, network policies, radio frequency management, failover, load balancing, wireless intrusion scanning and other functionalities required for the wireless users across the network.

IP Telephony Server: The IP Telephony Server provides the call control functions (voice switching) for the telephony operations in an enterprise network. Since the IP Phones connect to the computer networks, these IP Telephony Servers provide centralized administration and connectivity to PSTN Lines to all the IP Phones/ VOIP devices over the network including the assigning of extension/ DID numbers and IVR (Interactive Voice Response).

Distribution Switches: Distribution Switches provide an aggregation layer for network switching. The distribution switches connect to both copper UTP cable network as well as optical fiber networks. The distribution switches are connected to the core switch on one end and to the edge switches on the other. Generally, there may be one distribution switch for each department and a network is sometimes formed without the distribution/ aggregation layer by connecting the network endpoints directly to them.

Edge Switches: The Edge/ endpoint switches are basically Layer-2 switches that provide direct connectivity to the various network devices like PC’s, laptops, Wireless Access Points etc using the Copper UTP cables. They come in various configurations including 8 Port/ 16 Port, 24 Port, 48 Port etc. They support 10/100 Mbps as well as 10/100/1000 Mbps connectivity to the various network devices. Some of them even support POE (Power Over Ethernet) for electrical power required for operation of certain network devices (like Wireless Access Points, IP Phones etc) and some of them could be stacked to each other for providing a single management interface/ combined backplane for multiple such edge switches.

Wireless Access Points: The Wireless Access Points contain built-in radios which provide wireless signals for connecting certain network devices that has an in-built wireless adapter. Basically these access points send wireless signals that can be interpreted by the wireless enabled network clients for communicating the data/ information over the wireless medium. Their job is just to collect these signals, convert them in to wired signals and send it over the LAN network for the wireless controller to interpret them and take appropriate action. They generally have a coverage range of 20-30 meters indoor and 80-100 meters outdoor and each device can connect to more than 15 wireless devices within their coverage area. They operate in the 2.4 and 5 Ghz frequency spectrum.

Network Endpoints/ Devices: There are various network devices/ endpoints connecting to the LAN via edge switches/ wireless access points. Some of them include PC/ Laptop/ PDA etc for data connectivity, IP Phones, Cell Phones/Wi-Fi Phones, Soft Phones for voice connectivity, IP Surveillance Cameras/ IP Video Conferencing devices for video over IP. There are also network based accessories like network printers, MFP’s (Multi-Function Printers), Scanners etc. connecting to the enterprise computer network.

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Related Article: A basic Block Diagram of Active and Passive Components (Structured Cabling) used in a Local Area Network (LAN) with explanation

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