LAN Hardware SBA Slides PDF 2024

Topic 2: LAN Hardware [2.1 Wired Hardware] SUBJECT: LAN TECHNOLOGIES SEMESTER: S3, 2024 DCS SBA, DEC 2024 topics 2.1 Wired hardware ◦ Layer 2 switches ◦ Layer 3 switches ◦ Layer 4 switches 2.2 Wireless hardware ◦ Wireless components ◦ Client devices...

Topic 2: LAN Hardware [2.1 Wired Hardware] SUBJECT: LAN TECHNOLOGIES SEMESTER: S3, 2024 DCS SBA, DEC 2024 topics 2.1 Wired hardware ◦ Layer 2 switches ◦ Layer 3 switches ◦ Layer 4 switches 2.2 Wireless hardware ◦ Wireless components ◦ Client devices SBA, DEC 2024  Common Types of Networks LANs and WANs Network infrastructures vary greatly in terms of: Size of the area covered Number of users connected Number and types of services available Area of responsibility Two most common types of networks: Local Area Network (LAN) Wide Area Network (WAN). SBA, DEC 2024  Common Types of Networks LANs and WANs (cont.) A LAN is a network infrastructure that spans a small A WAN is a network infrastructure that spans a geographical area. wide geographical area. LAN WAN Interconnect end devices in a limited area. Interconnect LANs over wide geographical areas. Administered by a single organization or Typically administered by one or more service individual. providers. Provide high-speed bandwidth to internal Typically provide slower speed links between LANs. devices. SBA, DEC 2024 Devices in a Small Network SBA, DEC 2024 Devices in a Small Network Small Network Topologies The majority of businesses are small most of the business networks are also small. A small network design is usually simple. Small networks typically have a single WAN connection provided by DSL, cable, or an Ethernet connection. Large networks require an IT department to maintain, secure, and troubleshoot network devices and to protect organizational data. Small networks are managed by a local IT technician or by a contracted professional. Devices in a Small Network Device Selection for a Small Network Like large networks, small networks require planning and design to meet user requirements. Planning ensures that all requirements, cost factors, and deployment options are given due consideration. One of the first design considerations is the type of intermediary devices to use to support the network. Factors that must be considered when selecting network devices include: ◦ cost ◦ speed and types of ports/interfaces ◦ expandability ◦ operating system features and services Devices in a Small Network IP Addressing for a Small Network When implementing a network, create an IP addressing scheme and use it. All hosts and devices within an internetwork must have a unique address. Devices that will factor into the IP addressing scheme include the following: ◦ End user devices - The number and type of connections (i.e., wired, wireless, remote access) ◦ Servers and peripherals devices (e.g., printers and security cameras) ◦ Intermediary devices including switches and access points It is recommended that you plan, document, and maintain an IP addressing scheme based on device type. The use of a planned IP addressing scheme makes it easier to identify a type of device and to troubleshoot problems. Devices in a Small Network Redundancy in a Small Network In order to maintain a high degree of reliability, redundancy is required in the network design. Redundancy helps to eliminate single points of failure. Redundancy can be accomplished by installing duplicate equipment. It can also be accomplished by supplying duplicate network links for critical areas.  Devices in a Small Network Traffic Management The goal for a good network design is to enhance the productivity of the employees and minimize network downtime. The routers and switches in a small network should be configured to support real-time traffic, such as voice and video, in an appropriate manner relative to other data traffic. A good network design will implement quality of service (QoS). Priority queuing has four queues. The high- priority queue is always emptied first. Small Network Applications and Protocols SBA, DEC 2024 Small Network Applications and Protocols Common Applications After you have set it up, your network still needs certain types of applications and protocols in order to work. The network is only as useful as the applications that are on it. There are two forms of software programs or processes that provide access to the network: ◦ Network Applications: Applications that implement application layer protocols and are able to communicate directly with the lower layers of the protocol stack. ◦ Application Layer Services: For applications that are not network-aware, the programs that interface with the network and prepare the data for transfer. Small Network Applications and Protocols Common Protocols Network protocols support the applications and services used by employees in a small network. Network administrators commonly require access to network devices and servers. The two most common remote access solutions are Telnet and Secure Shell (SSH). Hypertext Transfer Protocol (HTTP) and Hypertext Transfer Protocol Secure (HTTP) are used between web clients and web servers. Simple Mail Transfer Protocol (SMTP) is used to send email, Post Office Protocol (POP3) or Internet Mail Access Protocol (IMAP) are used by clients to retrieve email. Small Network Applications and Protocols Common Protocols File Transfer Protocol (FTP) and Security File Transfer Protocol (SFTP) are used to download and upload files between a client and an FTP server. Dynamic Host Configuration Protocol (DHCP) is used by clients to acquire an IP configuration from a DHCP Server. The Domain Name Service (DNS) resolves domain names to IP addresses. Note: A server could provide multiple network services. For instance, a server could be an email, FTP and SSH server. Small Network Applications and Protocols Voice and Video Applications Businesses today are increasingly using IP telephony and streaming media to communicate with customers and business partners, as well as enabling their employees to work remotely. The network administrator must ensure the proper equipment is installed in the network and that the network devices are configured to ensure priority delivery.  Small Network Applications and Protocols Voice and Video Applications The factors that a small network administrator must consider when supporting real-time applications: ◦ Infrastructure - Does it have the capacity and capability to support real-time applications? ◦ VoIP - VoIP is typically less expensive than IP Telephony, but at the cost of quality and features. ◦ IP Telephony - This employs dedicated servers form call control and signaling. ◦ Real-Time Applications - The network must support Quality of Service (QoS) mechanisms to minimize latency issues. Real-Time Transport Protocol (RTP) and Real-Time Transport Control Protocol (RTCP) and two protocols that support real-time applications. WIRED HARDWARE -Switches -Routers SBA, DEC 2024 Switches Switches / Link Layer Switches The role of the switch: ◦ To receive incoming link-layer frames and forward them onto outgoing links The switch itself is transparent to the hosts and routers in the subnet; ◦ a host/router addresses a frame to another host/router (rather than addressing the frame to the switch) ◦ Hosts unaware that a switch will be receiving the frame and forwarding it.  Switch Function: Filtering and Forwarding Filtering ◦ the switch function that determines whether a frame should be forwarded to some interface or should just be dropped. Forwarding ◦ is the switch function that determines the interfaces to which a frame should be directed, and then moves the frame to those interfaces. Switch filtering and forwarding are done with a switch table. The switch table contains entries for some, but not necessarily all, of the hosts and routers on a LAN. An entry in the switch table contains(1) a MAC address, (2) the switch interface that leads toward that MAC address, and (3) the time at which the entry was placed in the table. SBA, DEC 2024 Switches are self learning Switches are self learning. ◦ It built its MAC table automatically, dynamically and autonomously without any intervention of the network administrator / configuration protocol SBA, DEC 2024 SBA, DEC 2024 SBA, DEC 2024 Type of switches Type of switches ◦ Unmanaged switches – plug and play, no configuration ◦ Managed switches – switch with operating system, implements additional features SBA, DEC 2024 Switches: Managed Switches Managed switches ◦ Per port configuration ◦ Port security – lock switch ports to a specific MAC address ◦ Virtual LANs (VLAN) – segmenting a physical network into multiple logical networks without having additional hardware ◦ VLAN trunking – transferring VLAN traffic between two or more switches ◦ And more… SBA, DEC 2024 SBA, DEC 2024 SBA, DEC 2024 SBA, DEC 2024 Routers SBA, DEC 2024 The Network Layer Network layer provides host to host communication service There is a piece of network layer in each and every host and router in the network. Role of Network Layer Move packets from a sending host to a receiving host To do so, two (2) important network layer functions: ◦ Forwarding ◦ Packet arrives at a router’s input link (e.g. Host H1 to Router R1) ◦ Move the packet to the appropriate output link (e.g. Router R1 to next router on a path on to Host H2) ◦ Routing ◦ Determine the route of path taken by packets as they flow from sender to receiver ◦ Use algorithms to calculate these paths (routing algorithms) (e.g. determine the path along which packets from from H1 to H2) ◦ A network-wide process that determines end-to-end paths that packets move from source to destination SBA, DEC 2024 SBA, DEC 2024 SBA, DEC 2024 Router Routers are network layer (Layer 3) devices Forwarding table ◦ A key element in every network router ◦ Forwards a packet by comparing the fields of the packet header and the forwarding table A piece of hardware / software that forwards packets based on their destination IP address. Contain at least two interfaces (connections). ◦ Example (Figure 7.1): ◦ One WAN connection – to the ISP (e.g. through cable modem) ◦ One LAN connection – to the LAN ◦ One LTE connection – failover to a cellular modem connection in the case WAN goes down SBA, DEC 2024 SBA, DEC 2024 SBA, DEC 2024 SBA, DEC 2024 SBA, DEC 2024 SBA, DEC 2024 SBA, DEC 2024 Switches vs Routers Routers are store-and-forward packet switches that forward packets using network-layer addresses. Switch forwards packets (frames as its is known in Layer 2) using MAC addresses. Router works at Layer 3. Switch works at Layer 2. Switch can work with plug-and-play, router needs to be configured before can be used, even at the most basic level. SBA, DEC 2024 Layer 3 Switches / Multilayer Switches Layer 3 Switches / Multilayer Switches Switch with routing capability Layer 3 Switches / Multilayer Switches Functions at both Layer 2 and Layer 3 Ports can be switch port or router port Four advanced capabilities: ◦ Load balancing ◦ Quality of service / traffic shaping ◦ Port bonding / port aggregation ◦ Network protection (IDS, port mirroring , proxy serving, AAA) SBA, DEC 2024