{"id":212050,"date":"2025-05-05T14:13:15","date_gmt":"2025-05-05T14:13:15","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=212050"},"modified":"2025-05-05T14:13:17","modified_gmt":"2025-05-05T14:13:17","slug":"a-layer-2-ethernet-switch-constructs-a-mac-address-table","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/05\/05\/a-layer-2-ethernet-switch-constructs-a-mac-address-table\/","title":{"rendered":"A Layer 2 Ethernet Switch Constructs A MAC Address Table"},"content":{"rendered":"\n

A Layer 2 Ethernet Switch Constructs A MAC Address Table. What Information Is Contained In This Table?<\/p>\n\n\n\n

A TCP And\/Or UDP Port Numbers Associated With Each Frame
B A Mapping Of IP Addresses To The Ports From Which They Were Learned
C IP Route Entries Learned Via Routing Protocols (E.G. OSPF)
D A Mapping Of MAC Addresses To The Ports From Which They Were<\/p>\n\n\n\n

The correct answer and explanation is :<\/strong><\/mark><\/p>\n\n\n\n

The correct answer is D: A mapping of MAC addresses to the ports from which they were learned<\/strong>.<\/p>\n\n\n\n

Explanation:<\/h3>\n\n\n\n

In Layer 2 Ethernet switches, the primary role is to forward Ethernet frames based on MAC (Media Access Control) addresses. A MAC address table<\/strong> (also known as a forwarding table<\/strong> or content-addressable memory (CAM) table<\/strong>) is maintained by the switch to facilitate efficient frame forwarding.<\/p>\n\n\n\n

How the MAC Address Table Works:<\/h4>\n\n\n\n

When a switch receives a frame, it checks the source MAC address<\/strong> and the port<\/strong> from which the frame was received. It then records this information in the MAC address table. The key information stored in the MAC address table is:<\/p>\n\n\n\n

    \n
  1. MAC Address<\/strong>: The unique identifier for network devices (like computers, printers, etc.) on the network. Each device has a unique MAC address assigned to its network interface card (NIC).<\/li>\n\n\n\n
  2. Port Number<\/strong>: The port on the switch where the frame was received.<\/li>\n<\/ol>\n\n\n\n

    For example, if a frame is received on port 1 with a source MAC address of 00:1A:2B:3C:4D:5E<\/code>, the switch will create an entry in its MAC address table that looks something like this:<\/p>\n\n\n\n

      \n
    • MAC Address: 00:1A:2B:3C:4D:5E<\/code><\/li>\n\n\n\n
    • Port: 1<\/code><\/li>\n<\/ul>\n\n\n\n

      Now, when a frame is later sent with a destination MAC address of 00:1A:2B:3C:4D:5E<\/code>, the switch will know to forward it out through port 1.<\/p>\n\n\n\n

      Why Other Options Are Incorrect:<\/h4>\n\n\n\n
        \n
      • A: TCP and\/or UDP Port Numbers<\/strong>: These are Layer 4 information (Transport Layer) and are not stored in a MAC address table. Layer 2 (Ethernet) switches do not deal with TCP or UDP port numbers.<\/li>\n\n\n\n
      • B: A Mapping of IP Addresses to the Ports From Which They Were Learned<\/strong>: This is the job of Layer 3 devices<\/strong> like routers, not Layer 2 switches. IP-to-port mappings are generally maintained in routing tables.<\/li>\n\n\n\n
      • C: IP Route Entries Learned via Routing Protocols (e.g., OSPF)<\/strong>: Routing tables with IP routes are maintained by routers, not Layer 2 switches.<\/li>\n<\/ul>\n\n\n\n

        Thus, option D<\/strong> is the correct answer because the MAC address table in Layer 2 switches maps MAC addresses to switch ports to determine where to forward frames.<\/p>\n","protected":false},"excerpt":{"rendered":"

        A Layer 2 Ethernet Switch Constructs A MAC Address Table. What Information Is Contained In This Table? A TCP And\/Or UDP Port Numbers Associated With Each FrameB A Mapping Of IP Addresses To The Ports From Which They Were LearnedC IP Route Entries Learned Via Routing Protocols (E.G. OSPF)D A Mapping Of MAC Addresses To […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-212050","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/212050","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=212050"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/212050\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=212050"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=212050"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=212050"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}