2.3 configure and deploy common Ethernet switching features. Flashcards
Data virtual local area network (VLAN)
A Data Virtual Local Area Network (VLAN) is a logical subdivision of a physical network that allows devices on different physical LANs to communicate as if they were on the same network. VLANs enable network segmentation, improving performance, security, and management by isolating broadcast traffic.
For the exam, you should know that VLANs can be configured using IEEE 802.1Q standard, which adds a VLAN tag to Ethernet frames to identify the VLAN membership. This tagging allows switches to properly route traffic to the appropriate VLAN. VLANs can also enhance security by isolating sensitive data or systems, limiting access based on user roles. Understanding how to implement and manage VLANs is essential for optimizing network performance and security in diverse environments.
Voice VLAN
A Voice VLAN is a specific type of virtual local area network (VLAN) dedicated to carrying voice traffic, typically from Voice over IP (VoIP) phones. By segregating voice traffic from data traffic, a Voice VLAN enhances the quality of service (QoS) for voice communications and improves overall network performance.
For the exam, you should know that Voice VLANs are usually configured on network switches to prioritize voice packets, ensuring they receive the necessary bandwidth and low latency required for clear audio quality. This is often accomplished by implementing QoS policies that give voice traffic higher priority over other types of traffic. Additionally, configuring a Voice VLAN can simplify network management by allowing separate handling of voice devices, which can help troubleshoot and maintain the VoIP system more effectively. Understanding how to set up and manage a Voice VLAN is important for ensuring reliable and high-quality voice communication in a network.
Port configurations
Port configurations refer to the settings applied to the physical or virtual ports on network devices, such as switches, routers, and firewalls. These configurations dictate how data is transmitted and received through each port, impacting network performance and security.
For the exam, you should know that port configurations can include settings such as enabling or disabling a port, configuring speed and duplex settings, assigning VLAN membership, and applying Quality of Service (QoS) policies. Additionally, security features like port security can be implemented to limit access based on MAC addresses or to prevent unauthorized devices from connecting to the network. Understanding how to configure and manage ports is crucial for optimizing network operations, ensuring proper traffic flow, and enhancing security across the network infrastructure.
Port tagging/802.1Q
Port tagging, defined by the IEEE 802.1Q standard, is a method used to identify and manage VLANs in Ethernet networks. When a frame is transmitted through a switch port configured for VLANs, the switch adds a VLAN tag to the Ethernet frame, which contains information about the VLAN membership.
For the exam, you should know that the VLAN tag includes a 12-bit VLAN ID, allowing for up to 4,096 distinct VLANs. This tagging enables switches to handle frames appropriately, ensuring they reach the correct VLAN while traversing the network. Port tagging is essential for supporting VLAN trunking, where multiple VLANs share the same physical link between switches or network devices. Understanding 802.1Q and its role in VLAN implementation is crucial for managing and optimizing network traffic and maintaining proper network segmentation.
Port aggregation
Port aggregation, also known as link aggregation or EtherChannel, is a networking technique that combines multiple physical network connections into a single logical link. This approach increases bandwidth and provides redundancy, enhancing overall network performance and reliability.
For the exam, you should know that port aggregation allows for load balancing of traffic across the aggregated links, which can prevent congestion and improve throughput. It also offers fault tolerance; if one link in the aggregated group fails, traffic can continue to flow over the remaining links. Standards such as IEEE 802.3ad (Link Aggregation Control Protocol or LACP) facilitate the automatic configuration and management of aggregated links. Understanding port aggregation is essential for optimizing network infrastructure, improving performance, and ensuring high availability in complex network environments.
Link Aggregation Control Protocol (LACP)
Link Aggregation Control Protocol (LACP) is a networking standard defined by IEEE 802.3ad that enables the automatic configuration of port aggregation on switches and network devices. LACP allows multiple physical network links to be combined into a single logical link, enhancing bandwidth and providing redundancy.
For the exam, you should know that LACP facilitates load balancing by distributing traffic across the aggregated links, which can improve overall network performance and reliability. Additionally, LACP helps maintain network stability; if one link in the aggregated group fails, traffic can continue to flow through the remaining links without interruption. LACP is commonly used in enterprise networks to connect switches and servers, ensuring efficient use of available bandwidth and improving fault tolerance. Understanding how to configure and manage LACP is important for optimizing network performance and ensuring redundancy in network designs.
Duplex
Duplex refers to the capability of a network connection to transmit data in one direction or both directions. There are two primary types of duplex configurations: half-duplex and full-duplex.
For the exam, you should know that in half-duplex mode, data transmission can occur in both directions, but not simultaneously. This means that while one device is sending data, the other must wait to respond, leading to potential delays. In contrast, full-duplex mode allows for simultaneous two-way data transmission, which increases the efficiency and performance of network communications. Full-duplex is commonly used in modern Ethernet networks, while half-duplex may still be seen in older technologies or specific applications. Understanding the differences between duplex modes is important for configuring network devices and optimizing communication performance.
Port Configurations - Speed
Port configurations for speed involve setting the transmission rate of a network device’s port to match the capabilities of connected devices, ensuring optimal communication. This configuration is crucial for maintaining performance and avoiding issues related to speed mismatches.
For the exam, you should know that common Ethernet speeds include 10 Mbps, 100 Mbps, 1 Gbps, and 10 Gbps. Most modern switches and devices support auto-negotiation, allowing them to automatically select the best possible speed and duplex settings. However, in some cases, manual configuration may be necessary, especially in environments with specific requirements or legacy equipment. Correctly configuring port speed is vital for maximizing bandwidth utilization, minimizing collisions, and enhancing overall network efficiency. Understanding the principles of port speed configuration is essential for effective network design and troubleshooting.
Port Configurations - Flow control
Flow control is a network feature that manages the rate of data transmission between devices to prevent overwhelming a receiving device’s buffer. It ensures that the sender does not send data faster than the receiver can process it, thus maintaining data integrity and preventing packet loss.
For the exam, you should know that common flow control mechanisms include IEEE 802.3x, which uses pause frames to temporarily halt data transmission when a device’s buffer reaches a certain threshold. Additionally, flow control settings can often be configured on switches and network interfaces, allowing administrators to enable or disable flow control based on specific network requirements. Proper flow control configuration is essential for optimizing network performance, especially in high-traffic environments, by ensuring smooth data transfer and minimizing congestion. Understanding flow control principles helps in troubleshooting network issues and enhancing overall network reliability.
Port mirroring
Port mirroring is a network feature that allows the duplication of network traffic from one or more ports on a switch to a designated monitoring port. This is typically used for monitoring, analyzing, and troubleshooting network performance and security.
For the exam, you should know that port mirroring enables network administrators to capture and analyze traffic without affecting the flow of data in the network. Common use cases include traffic analysis, intrusion detection, and performance monitoring. When configured, the switch copies packets from the source port(s) to the destination port, where monitoring tools or intrusion detection systems can analyze the data in real time. Understanding how to set up and utilize port mirroring is essential for effective network management, security monitoring, and troubleshooting.
Port security
Port security is a network security feature implemented on switches to control access to a port based on the MAC addresses of devices connected to it. This feature helps prevent unauthorized access and potential network attacks by limiting the number of devices that can connect to a specific port.
For the exam, you should know that port security can be configured to allow only specific MAC addresses, limit the number of MAC addresses per port, and take actions when security violations occur (e.g., shutting down the port, sending alerts, or logging events). This functionality is essential for enhancing network security, particularly in environments where sensitive data is transmitted. Understanding how to configure and manage port security is crucial for protecting network resources and maintaining a secure networking environment.
Jumbo frames
Jumbo frames are Ethernet frames that exceed the standard maximum transmission unit (MTU) size of 1,500 bytes, typically allowing sizes of up to 9,000 bytes or more. This larger frame size enables more data to be transmitted in a single packet, reducing the overhead associated with processing multiple smaller packets.
For the exam, you should know that using jumbo frames can improve network efficiency and performance, particularly in high-bandwidth environments such as data centers or for applications like video streaming and large file transfers. However, all devices on the network path, including switches and routers, must support jumbo frames for them to be effective. Misconfiguration can lead to fragmentation or dropped packets. Understanding how to configure and implement jumbo frames is important for optimizing network performance and ensuring compatibility across the network infrastructure.
Auto-medium-dependent interface crossover (MDI-X)
Auto-Medium-Dependent Interface Crossover (MDI-X) is a feature found in network devices that automatically configures the ports to work as either a standard Ethernet (MDI) or a crossover Ethernet (MDI-X) connection. This functionality eliminates the need for crossover cables when connecting devices directly.
For the exam, you should know that MDI ports are used to connect devices to network devices (like switches), while MDI-X ports are used to connect devices directly to one another (like connecting two computers). With MDI-X, the network device can automatically detect and adjust its port configuration, making it more flexible and user-friendly. This feature is particularly useful in simplifying network setups, reducing cable requirements, and minimizing configuration errors. Understanding MDI and MDI-X is important for effective network design and troubleshooting.
Media access control (MAC) address tables
Media Access Control (MAC) address tables, also known as forwarding tables or content addressable memory (CAM) tables, are used by network switches to map MAC addresses to specific switch ports. This mapping allows the switch to efficiently forward frames to the appropriate destination based on the MAC address contained in the Ethernet frames.
For the exam, you should know that when a switch receives a frame, it examines the source MAC address and records it in the MAC address table along with the port number on which it was received. This enables the switch to learn the locations of devices on the network and to make forwarding decisions without flooding all ports with broadcast traffic. MAC address tables can also age out entries after a period of inactivity to accommodate changes in the network. Understanding MAC address tables is crucial for grasping how switches optimize network performance and manage data flow in local area networks (LANs).
Power over Ethernet (PoE)/ Power over Ethernet plus (PoE+
Power over Ethernet (PoE) is a technology that enables the transmission of electrical power along with data over standard Ethernet cabling (typically Cat 5e or higher). This allows devices such as IP cameras, VoIP phones, and wireless access points to receive power and network connectivity through a single cable, simplifying installation and reducing the need for separate power sources.
For the exam, you should know that there are different standards for PoE, including PoE (IEEE 802.3af), which can deliver up to 15.4 watts per port, and Power over Ethernet Plus (PoE+) (IEEE 802.3at), which can provide up to 30 watts per port. PoE is widely used in enterprise environments to enhance flexibility and reduce installation costs for network devices. Understanding PoE and PoE+ specifications is essential for planning and deploying network infrastructures that rely on powered devices.
