This post continues from Part 1 and covers a few more important networking concepts. These terms often come up when learning how data moves through a network, especially when understanding how devices identify each other, how applications communicate, and how data is structured at each layer.<\/p>\n\n\n\n
1. MAC Address \u2013 Device-Level Identification<\/strong><\/p>\n\n\n\n A MAC (Media Access Control) address is a unique identifier assigned to a device\u2019s network interface card (NIC). It works at the Data Link layer (Layer 2) and is mainly used for communication within a local area network.<\/p>\n\n\n\n Format:<\/p>\n\n\n\n Purpose:<\/p>\n\n\n\n MAC addresses are used to represent the Next-Hop (Next device) in communication.<\/strong><\/p>\n\n\n\n 2. Port Numbers \u2013 Process-to-Process Communication<\/strong><\/p>\n\n\n\n When two devices communicate, it\u2019s not enough to just reach the device (IP address) \u2014 we also need to reach the correct application or process<\/strong> on that device. That\u2019s where port numbers<\/strong> come in.<\/p>\n\n\n\n Port numbers are part of the Transport layer (Layer 4)<\/strong> and are used by protocols like TCP and UDP.<\/p>\n\n\n\n Example:<\/strong><\/p>\n\n\n\n Port Ranges:<\/strong><\/p>\n\n\n\n When your browser connects to a website:<\/p>\n\n\n\n 3. Protocol Data Unit (PDU) \u2013 The Payload at Each Layer<\/strong><\/p>\n\n\n\n A Protocol Data Unit (PDU)<\/strong> is the formatted unit of data<\/strong> that each layer of the OSI model works with. As data moves down the layers, it gets wrapped with the necessary headers at each stage.<\/p>\n\n\n\n Here\u2019s how the PDU is named at each layer:<\/p>\n\n\n\n Example:<\/p>\n\n\n\n Understanding these terms helps when you\u2019re analyzing packet captures or discussing where certain headers are added.<\/p>\n\n\n\n 4. Types of Communication \u2013 Who Gets the Data?<\/strong><\/p>\n\n\n\n When a device sends data, it can send it to one or many recipients. Here are the common types of network communication:<\/p>\n\n\n\n Unicast<\/strong><\/p>\n\n\n\n Multicast<\/strong><\/p>\n\n\n\n Broadcast<\/strong><\/p>\n\n\n\n Anycast<\/strong><\/p>\n\n\n\n Summary Table<\/strong><\/p>\n\n\n\n <\/p>\n<\/body>","protected":false},"excerpt":{"rendered":" This post continues from Part 1 and covers a few more important networking concepts. These terms often come up when learning how data moves through a network, especially when understanding how devices identify each other, how applications communicate, and how data is structured at each layer. 1. MAC Address \u2013 Device-Level Identification A MAC (Media […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"wp-custom-template-post-with-sidebar2","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[330],"tags":[339,338,40,335,337,336,334,332,333],"class_list":["post-1231","post","type-post","status-publish","format-standard","hentry","category-networking-fundamentals","tag-anycast","tag-broadcast","tag-mac-address","tag-multicast","tag-networking-basics","tag-pdu","tag-port-numbers","tag-protocol-data-unit","tag-unicast"],"yoast_head":"\n\n
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Range<\/strong><\/td> Purpose<\/strong><\/td><\/tr><\/thead> 0 \u2013 1023<\/td> Well-known ports<\/strong> (e.g., HTTP, FTP)<\/td><\/tr> 1024 \u2013 49151<\/td> Registered ports<\/strong> (for user processes)<\/td><\/tr> 49152 \u2013 65535<\/td> Dynamic\/Ephemeral ports<\/strong> (temporary)<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n \n
\n\n\n\nOSI Layer<\/strong><\/td> PDU Name<\/strong><\/td><\/tr><\/thead> Application<\/td> Data<\/td><\/tr> Transport<\/td> Segment (TCP) \/ Datagram (UDP)<\/td><\/tr> Network<\/td> Packet or Datagram<\/td><\/tr> Data Link<\/td> Frame<\/td><\/tr> Physical<\/td> Bits<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n \n
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\n\n\n\nTerm<\/strong><\/td> What It Refers To<\/strong><\/td><\/tr><\/thead> MAC Address<\/td> Unique Layer 2 identifier for a device<\/td><\/tr> Port Number<\/td> Layer 4 identifier for application traffic<\/td><\/tr> PDU<\/td> Data format unit used at each OSI layer<\/td><\/tr> Unicast<\/td> One-to-one communication<\/td><\/tr> Multicast<\/td> One-to-selected group communication<\/td><\/tr> Broadcast<\/td> One-to-all in the same network<\/td><\/tr> Anycast<\/td> One-to-nearest receiver (IP shared)<\/td><\/tr> <\/td> \u00a0<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
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