sabrina lan wired

LAN Hardware [Wired]

• LAN hardware includes Layer 2 switches, Layer 3 switches, and Layer 4 switches.

Wireless Hardware

• Wireless components are included, as are client devices.

LANs and WANs

• Network infrastructures differ in area covered, number of users, services available, and responsibilities.
• Two primary network types exist: LAN (Local Area Network) and WAN (Wide Area Network).
• LANs cover small geographical areas, are administered by a single entity, and offer high-bandwidth connections.
• WANs cover large geographical areas, are generally managed by several service providers, and characteristically provide slower connections between multiple LANs.

Devices in a Small Network

• Most business networks are small.
• Small network designs are usually simple.
• Small networks typically have one WAN connection (DSL, cable, or Ethernet).
• Large networks often require dedicated IT personnel for maintenance, security, and troubleshooting.

Device Selection for a Small Network

• Small network design needs to meet all requirements considering cost, deployment options.
• Important design consideration is the type of intermediary devices.
• Key selection factors for network devices include cost, speed and port types, expandability, and operating system features.

IP Addressing for a Small Network

• All devices within an internetwork need a unique IP address.
• End user devices (wired, wireless, remote access), servers, peripherals (printers, security cameras), and intermediary devices (switches, access points) all require IP addresses.
• Document and maintain a planned IP addressing scheme based on device types for easier identification and troubleshooting.

Redundancy in a Small Network

• High reliability requires redundancy in network design to eliminate single points of failure.
• Redundancy is accomplished by installing duplicate equipment and providing duplicate network links in critical areas.
• Examples include redundant servers, links, switches, and routers.

Traffic Management

• Network design aims to improve employee productivity and minimize network downtime.
• Routers and switches should support real-time traffic (e.g., voice, video) in a manner appropriate to other data traffic.
• Quality of Service (QoS) is a key concept for managing network traffic priorities.

Small Network Applications and Protocols

• Networks need applications and protocols to function. Two key forms are: network applications and application layer services.
• Network applications use protocols to communicate with lower network layers.
• Application layer services prepare non-network-aware applications for network transfer.

Common Protocols

• Network administrators often need access to network devices/servers. Telnet and SSH are common remote access solutions.
• HTTP (Hypertext Transfer Protocol) and HTTPS (Hypertext Transfer Protocol Secure) are used between web clients and web servers.
• SMTP (Simple Mail Transfer Protocol) sends email; POP3 (Post Office Protocol 3) and IMAP (Internet Message Access Protocol) receive it.
• FTP (File Transfer Protocol) and SFTP (Secure File Transfer Protocol) transfer files.
• DHCP (Dynamic Host Configuration Protocol) assigns IP configurations to clients.
• DNS (Domain Name System) translates domain names to IP addresses.

Voice and Video Applications

• Businesses increasingly use IP telephony and streaming media to enhance communication and remote work capabilities.
• Network administrators must ensure proper equipment installation and configuration for reliable priority delivery.

Voice and Video Applications: Factors to Consider

• Infrastructure needs appropriate capacity for real-time applications.
• VoIP (Voice over Internet Protocol) is typically less expensive than IP telephony but often has lower quality.
• IP telephony uses dedicated servers for call control and signaling.
• Real-time applications require QoS mechanisms (e.g., RTP, RTCP) to minimize latency issues.

Switches

• Switches' role is to forward incoming link-layer frames onto outgoing links.
• Switches are transparent to hosts and routers in the subnet; there is no direct addressing to the switch.
• Hosts are unaware that a switch is receiving and forwarding their frames.
• Switch functionality includes filtering and forwarding, utilizing a switch table.

Switches are Self-Learning

• Switches automatically build MAC tables, dynamically and without admin intervention.

Type of Switches

• Unmanaged switches (plug-and-play, no configuration).
• Managed switches (operating system, additional features).

Managed Switches

• Per-port configuration of managed switches is possible.
• Port security allows locking switch ports to specific MAC addresses.
• Virtual LANs (VLANs) segment physical networks into logical networks without additional hardware.
• VLAN trunking transfers VLAN traffic between switches.

Routers

• Routers are network layer devices (Layer 3).
• Essential function of a router is forwarding tables.
• A router forwards packets based on their destination IP addresses.
• A typical router has at least two interfaces.

Routing Table

• The routing table contains routes to various destinations, each with a gateway, netmask, and type.
• Routing tables help in determining paths for IP packets.

Comparison of Switches and Routers

• Routers operate at Layer 3 of the OSI model using network-layer addresses, while switches operate at Layer 2 using MAC addresses.
• Switches often use plug-and-play, whereas routers typically require configuration.
• Hubs, unlike routers and switches, don't isolate traffic.

Routing Table and Network

• The routing table (Figure 7-8) contains data determining routes for packets.
• The diagram in Figure 7-9 illustrates a network based on the routing table (Figure 7-7). A single router manages traffic between two subnets (10.12.14.0/24 and 76.30.4.0/24) with proper routing protocols.

Routing Algorithm

• Routing algorithms determine values in forward tables as described in Figure 4.2.

Layer 3 Switches/Multilayer Switches

• Layer 3 switches function at both Layer 2 and Layer 3.
• Layer 3 switches have ports that can function as switch ports or router ports.