{"id":35185,"date":"2025-10-28T10:45:45","date_gmt":"2025-10-28T03:45:45","guid":{"rendered":"https:\/\/interdata.vn\/blog\/?p=35185"},"modified":"2025-10-28T15:57:22","modified_gmt":"2025-10-28T08:57:22","slug":"vlan-la-gi","status":"publish","type":"post","link":"https:\/\/interdata.vn\/blog\/vlan-la-gi\/","title":{"rendered":"VLAN l\u00e0 g\u00ec? Ph\u00e2n lo\u1ea1i, L\u1ee3i \u00edch, C\u00e1ch ho\u1ea1t \u0111\u1ed9ng &#038; C\u00e1ch c\u1ea5u h\u00ecnh"},"content":{"rendered":"<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_85 counter-hierarchy ez-toc-counter ez-toc-white ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">N\u1ed8I DUNG<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 eztoc-toggle-hide-by-default' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/interdata.vn\/blog\/vlan-la-gi\/#Mang-VLAN-la-gi\" >M\u1ea1ng VLAN l\u00e0 g\u00ec?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/interdata.vn\/blog\/vlan-la-gi\/#VLAN-hoat-dong-nhu-the-nao\" >VLAN ho\u1ea1t \u0111\u1ed9ng nh\u01b0 th\u1ebf n\u00e0o?<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/interdata.vn\/blog\/vlan-la-gi\/#VLAN-ID-va-Pham-vi-hoat-dong\" >VLAN ID v\u00e0 Ph\u1ea1m vi ho\u1ea1t \u0111\u1ed9ng<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/interdata.vn\/blog\/vlan-la-gi\/#Mang-VLAN-duoc-phan-loai-nhu-the-nao\" >M\u1ea1ng VLAN \u0111\u01b0\u1ee3c ph\u00e2n lo\u1ea1i nh\u01b0 th\u1ebf n\u00e0o?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/interdata.vn\/blog\/vlan-la-gi\/#Phan-biet-Access-Port-va-Trunk-Port\" >Ph\u00e2n bi\u1ec7t Access Port v\u00e0 Trunk Port<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/interdata.vn\/blog\/vlan-la-gi\/#Uu-va-nhuoc-diem-cua-VLAN-la-gi\" >\u01afu v\u00e0 nh\u01b0\u1ee3c \u0111i\u1ec3m c\u1ee7a VLAN l\u00e0 g\u00ec?<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/interdata.vn\/blog\/vlan-la-gi\/#Uu-diem-vuot-troi-cua-VLAN\" >\u01afu \u0111i\u1ec3m v\u01b0\u1ee3t tr\u1ed9i c\u1ee7a VLAN<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/interdata.vn\/blog\/vlan-la-gi\/#Nhuoc-diem-va-thach-thuc-cua-VLAN\" >Nh\u01b0\u1ee3c \u0111i\u1ec3m v\u00e0 th\u00e1ch th\u1ee9c c\u1ee7a VLAN<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/interdata.vn\/blog\/vlan-la-gi\/#Ung-dung-cua-mang-VLAN\" >\u1ee8ng d\u1ee5ng c\u1ee7a m\u1ea1ng VLAN<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-10\" href=\"https:\/\/interdata.vn\/blog\/vlan-la-gi\/#Cach-cau-hinh-va-thiet-lap-mang-VLAN\" >C\u00e1ch c\u1ea5u h\u00ecnh v\u00e0 thi\u1ebft l\u1eadp m\u1ea1ng VLAN<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-11\" href=\"https:\/\/interdata.vn\/blog\/vlan-la-gi\/#Buoc-1-Tao-VLAN\" >B\u01b0\u1edbc 1: T\u1ea1o VLAN<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-12\" href=\"https:\/\/interdata.vn\/blog\/vlan-la-gi\/#Buoc-2-Gan-cong-vao-VLAN\" >B\u01b0\u1edbc 2: G\u00e1n c\u1ed5ng v\u00e0o VLAN<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-13\" href=\"https:\/\/interdata.vn\/blog\/vlan-la-gi\/#Buoc-3-Kiem-tra-va-luu-cau-hinh\" >B\u01b0\u1edbc 3: Ki\u1ec3m tra v\u00e0 l\u01b0u c\u1ea5u h\u00ecnh<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-14\" href=\"https:\/\/interdata.vn\/blog\/vlan-la-gi\/#So-sanh-su-khac-nhau-giua-mang-LAN-va-VLAN\" >So s\u00e1nh s\u1ef1 kh\u00e1c nhau gi\u1eefa m\u1ea1ng LAN v\u00e0 VLAN<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-15\" href=\"https:\/\/interdata.vn\/blog\/vlan-la-gi\/#VLAN-Tagging-va-Standard-VLAN\" >VLAN Tagging v\u00e0 Standard VLAN<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-16\" href=\"https:\/\/interdata.vn\/blog\/vlan-la-gi\/#Chuan-IEEE-8021Q-la-gi\" >Chu\u1ea9n IEEE 802.1Q l\u00e0 g\u00ec?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-17\" href=\"https:\/\/interdata.vn\/blog\/vlan-la-gi\/#Native-VLAN-la-gi\" >Native VLAN l\u00e0 g\u00ec?<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-18\" href=\"https:\/\/interdata.vn\/blog\/vlan-la-gi\/#Cau-hoi-thuong-gap-ve-mang-VLAN-FAQs\" >C\u00e2u h\u1ecfi th\u01b0\u1eddng g\u1eb7p v\u1ec1 m\u1ea1ng VLAN (FAQs)<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-19\" href=\"https:\/\/interdata.vn\/blog\/vlan-la-gi\/#VLAN-Voice-la-gi\" >VLAN Voice l\u00e0 g\u00ec?<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-20\" href=\"https:\/\/interdata.vn\/blog\/vlan-la-gi\/#VLAN-va-Subnet-khac-nhau-nhu-the-nao\" >VLAN v\u00e0 Subnet kh\u00e1c nhau nh\u01b0 th\u1ebf n\u00e0o?<\/a><\/li><\/ul><\/li><\/ul><\/nav><\/div>\n<p>M\u1ea1ng VLAN l\u00e0 k\u1ef9 thu\u1eadt ph\u00e2n \u0111o\u1ea1n m\u1ea1ng LAN v\u1eadt l\u00fd th\u00e0nh nhi\u1ec1u mi\u1ec1n logic nh\u1ecf, gi\u00fap t\u1ed1i \u01b0u hi\u1ec7u su\u1ea5t v\u00e0 t\u0103ng b\u1ea3o m\u1eadt m\u1ea1ng. B\u00e0i vi\u1ebft n\u00e0y c\u1ee7a InterData cung c\u1ea5p ki\u1ebfn th\u1ee9c to\u00e0n di\u1ec7n v\u1ec1 <strong>m\u1ea1ng LAN \u1ea3o (VLAN)<\/strong>, t\u1eeb l\u00fd thuy\u1ebft c\u01a1 b\u1ea3n (kh\u00e1i ni\u1ec7m, nguy\u00ean l\u00fd ho\u1ea1t \u0111\u1ed9ng) \u0111\u1ebfn c\u00e1c b\u01b0\u1edbc h\u01b0\u1edbng d\u1eabn c\u1ea5u h\u00ecnh VLAN chi ti\u1ebft tr\u00ean c\u00e1c thi\u1ebft b\u1ecb m\u1ea1ng ph\u1ed5 bi\u1ebfn \u0111\u1ec3 tri\u1ec3n khai v\u00e0 qu\u1ea3n l\u00fd h\u1ec7 th\u1ed1ng m\u1ea1ng m\u1ed9t c\u00e1ch chuy\u00ean nghi\u1ec7p h\u01a1n.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Mang-VLAN-la-gi\"><\/span>M\u1ea1ng VLAN l\u00e0 g\u00ec?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p><strong>VLAN<\/strong> l\u00e0 vi\u1ebft t\u1eaft c\u1ee7a Virtual Local Area Network, t\u1ea1m d\u1ecbch l\u00e0 M\u1ea1ng LAN \u1ea3o hay M\u1ea1ng c\u1ee5c b\u1ed9 \u1ea3o. \u0110\u00e2y l\u00e0 m\u1ed9t k\u1ef9 thu\u1eadt \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng r\u1ed9ng r\u00e3i \u0111\u1ec3 ph\u00e2n \u0111o\u1ea1n m\u1ed9t m\u1ea1ng LAN v\u1eadt l\u00fd th\u00e0nh nhi\u1ec1u ph\u00e2n \u0111o\u1ea1n m\u1ea1ng logic nh\u1ecf h\u01a1n, \u0111\u1ed9c l\u1eadp v\u1edbi nhau.<\/p>\n<p>Hi\u1ec3u \u0111\u01a1n gi\u1ea3n, m\u1ed9t VLAN cho ph\u00e9p c\u00e1c thi\u1ebft b\u1ecb (m\u00e1y t\u00ednh, m\u00e1y in, m\u00e1y ch\u1ee7,&#8230;) \u0111\u01b0\u1ee3c nh\u00f3m l\u1ea1i v\u1edbi nhau d\u1ef1a tr\u00ean ch\u1ee9c n\u0103ng, ph\u00f2ng ban ho\u1eb7c \u1ee9ng d\u1ee5ng, b\u1ea5t k\u1ec3 v\u1ecb tr\u00ed v\u1eadt l\u00fd c\u1ee7a ch\u00fang trong m\u1ea1ng. \u0110i\u1ec1u n\u00e0y c\u00f3 ngh\u0129a l\u00e0, m\u1ed9t nh\u00e2n vi\u00ean ph\u00f2ng K\u1ebf to\u00e1n \u1edf t\u1ea7ng 1 c\u00f3 th\u1ec3 thu\u1ed9c c\u00f9ng m\u1ed9t VLAN v\u1edbi nh\u00e2n vi\u00ean K\u1ebf to\u00e1n \u1edf t\u1ea7ng 5, mi\u1ec5n l\u00e0 h\u1ecd c\u00f9ng chung nh\u00f3m logic.<\/p>\n<figure id=\"attachment_35203\" aria-describedby=\"caption-attachment-35203\" style=\"width: 800px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-35203\" src=\"https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/10\/Mang-VLAN-la-gi.jpg\" alt=\"M\u1ea1ng VLAN l\u00e0 g\u00ec\" width=\"800\" height=\"500\" title=\"\" srcset=\"https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/10\/Mang-VLAN-la-gi.jpg 800w, https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/10\/Mang-VLAN-la-gi-300x188.jpg 300w, https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/10\/Mang-VLAN-la-gi-768x480.jpg 768w\" sizes=\"auto, (max-width: 800px) 100vw, 800px\" \/><figcaption id=\"caption-attachment-35203\" class=\"wp-caption-text\">M\u1ea1ng VLAN l\u00e0 g\u00ec<\/figcaption><\/figure>\n<h2><span class=\"ez-toc-section\" id=\"VLAN-hoat-dong-nhu-the-nao\"><\/span>VLAN ho\u1ea1t \u0111\u1ed9ng nh\u01b0 th\u1ebf n\u00e0o?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>C\u01a1 ch\u1ebf ho\u1ea1t \u0111\u1ed9ng c\u1ee7a VLAN xoay quanh vi\u1ec7c:<\/p>\n<ul>\n<li>Khi m\u1ed9t g\u00f3i tin \u0111\u01b0\u1ee3c g\u1eedi t\u1eeb m\u00e1y tr\u1ea1m (host) v\u00e0o c\u1ed5ng Access Port c\u1ee7a switch, switch d\u1ef1a v\u00e0o c\u1ea5u h\u00ecnh VLAN c\u1ee7a c\u1ed5ng \u0111\u00f3 \u0111\u1ec3 g\u00e1n VLAN ID cho g\u00f3i tin, x\u00e1c \u0111\u1ecbnh thi\u1ebft b\u1ecb thu\u1ed9c VLAN n\u00e0o.<\/li>\n<li>Khi g\u00f3i tin c\u1ea7n truy\u1ec1n qua nhi\u1ec1u switch qua k\u00eanh trunk, switch s\u1ebd s\u1eed d\u1ee5ng c\u01a1 ch\u1ebf VLAN Tagging theo chu\u1ea9n IEEE 802.1Q \u0111\u1ec3 ch\u00e8n th\u00eam th\u1ebb VLAN v\u00e0o Header c\u1ee7a khung Ethernet. Th\u1ebb n\u00e0y ch\u1ee9a VLAN ID gi\u00fap switch ti\u1ebfp theo nh\u1eadn di\u1ec7n \u0111\u01b0\u1ee3c g\u00f3i tin thu\u1ed9c VLAN n\u00e0o.<\/li>\n<li>Switch \u1edf ph\u00eda nh\u1eadn s\u1ebd \u0111\u1ecdc VLAN tag \u0111\u1ec3 quy\u1ebft \u0111\u1ecbnh g\u00f3i tin s\u1ebd \u0111i qua c\u1ed5ng n\u00e0o v\u00e0 ch\u1ec9 chuy\u1ec3n ti\u1ebfp trong ph\u1ea1m vi VLAN \u0111\u00f3, c\u00e1ch ly l\u01b0u l\u01b0\u1ee3ng gi\u1eefa c\u00e1c VLAN kh\u00e1c nhau.<\/li>\n<\/ul>\n<p>C\u1ee5 th\u1ec3, th\u1ebb VLAN 802.1Q \u0111\u01b0\u1ee3c ch\u00e8n v\u00e0o gi\u1eefa \u0111\u1ecba ch\u1ec9 MAC ngu\u1ed3n v\u00e0 tr\u01b0\u1eddng EtherType trong frame Ethernet ban \u0111\u1ea7u, gi\u00fap m\u1edf r\u1ed9ng m\u1ed9t k\u1ebft n\u1ed1i v\u1eadt l\u00fd cho nhi\u1ec1u VLAN m\u00e0 kh\u00f4ng g\u00e2y h\u1ed7n lo\u1ea1n l\u01b0u l\u01b0\u1ee3ng. Khi frame \u0111\u01b0\u1ee3c tagging, k\u00edch th\u01b0\u1edbc frame c\u0169ng \u0111\u01b0\u1ee3c \u0111i\u1ec1u ch\u1ec9nh t\u0103ng th\u00eam 4 byte cho th\u1ebb vlan n\u00e0y.<\/p>\n<p>VLAN ho\u1ea1t \u0111\u1ed9ng b\u1eb1ng c\u00e1ch g\u1eafn nh\u00e3n VLAN tag (802.1Q) v\u00e0o frame Ethernet \u0111\u1ec3 ph\u00e2n bi\u1ec7t c\u00e1c VLAN tr\u00ean m\u1ea1ng v\u00e0 c\u00e1c switch s\u1eed d\u1ee5ng th\u1ebb \u0111\u00f3 \u0111\u1ec3 ph\u00e2n t\u00e1ch, \u0111\u1ecbnh tuy\u1ebfn g\u00f3i tin \u0111\u00fang VLAN, \u0111\u1ea3m b\u1ea3o an to\u00e0n v\u00e0 t\u00e1ch bi\u1ec7t l\u01b0u l\u01b0\u1ee3ng m\u1ea1ng gi\u1eefa c\u00e1c VLAN kh\u00e1c nhau.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"VLAN-ID-va-Pham-vi-hoat-dong\"><\/span>VLAN ID v\u00e0 Ph\u1ea1m vi ho\u1ea1t \u0111\u1ed9ng<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>M\u1ed7i <strong>VLAN<\/strong> trong m\u1ea1ng \u0111\u1ec1u \u0111\u01b0\u1ee3c g\u00e1n m\u1ed9t s\u1ed1 \u0111\u1ecbnh danh duy nh\u1ea5t g\u1ecdi l\u00e0 <strong>VLAN ID<\/strong>. \u0110\u00e2y l\u00e0 m\u1ed9t tr\u01b0\u1eddng 12-bit, cho ph\u00e9p \u0111\u1ecbnh ngh\u0129a t\u1ed5ng c\u1ed9ng $2^{12} = 4096$ <strong>VLAN<\/strong> kh\u00e1c nhau (t\u1eeb 0 \u0111\u1ebfn 4095).<\/p>\n<p>Ph\u1ea1m vi c\u1ee7a c\u00e1c <strong>VLAN ID<\/strong> \u0111\u01b0\u1ee3c chia th\u00e0nh hai lo\u1ea1i ch\u00ednh:<\/p>\n<p><strong>VLAN ID Ph\u1ea1m vi Chu\u1ea9n (Normal Range &#8211; ID 1 \u0111\u1ebfn 1005):<\/strong><\/p>\n<p>C\u00e1c <strong>VLAN<\/strong> trong ph\u1ea1m vi n\u00e0y th\u01b0\u1eddng \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong c\u00e1c m\u1ea1ng quy m\u00f4 nh\u1ecf v\u00e0 v\u1eeba.<\/p>\n<ul>\n<li><strong>VLAN<\/strong> ID 1 l\u00e0 <strong>VLAN<\/strong> m\u1eb7c \u0111\u1ecbnh (Default <strong>VLAN<\/strong>), lu\u00f4n t\u1ed3n t\u1ea1i v\u00e0 kh\u00f4ng th\u1ec3 x\u00f3a \u0111\u01b0\u1ee3c.<\/li>\n<li><strong>VLAN<\/strong> ID 1002 \u0111\u1ebfn 1005 l\u00e0 c\u00e1c <strong>VLAN<\/strong> \u0111\u01b0\u1ee3c d\u1ef1 tr\u1eef cho c\u00e1c c\u00f4ng ngh\u1ec7 c\u0169 nh\u01b0 FDDI v\u00e0 Token Ring.<\/li>\n<\/ul>\n<p><strong>VLAN ID Ph\u1ea1m vi M\u1edf r\u1ed9ng (Extended Range &#8211; ID 1006 \u0111\u1ebfn 4094):<\/strong><\/p>\n<p>D\u00f9ng cho c\u00e1c m\u1ea1ng l\u1edbn, nh\u00e0 cung c\u1ea5p d\u1ecbch v\u1ee5 ho\u1eb7c c\u00e1c c\u00f4ng ngh\u1ec7 \u0111\u1eb7c bi\u1ec7t.<\/p>\n<p>C\u00e1c <strong>VLAN<\/strong> n\u00e0y kh\u00f4ng \u0111\u01b0\u1ee3c l\u01b0u tr\u1eef trong t\u1ec7p c\u1ea5u h\u00ecnh <strong>VLAN<\/strong> m\u1eb7c \u0111\u1ecbnh (VLAN.dat tr\u00ean Cisco) v\u00e0 ph\u1ea3i \u0111\u01b0\u1ee3c c\u1ea5u h\u00ecnh b\u1eb1ng tay tr\u00ean t\u1eebng <strong>Switch<\/strong> (tr\u1eeb khi s\u1eed d\u1ee5ng giao th\u1ee9c <strong>VLAN<\/strong> Trunking Protocol &#8211; VTP, nh\u01b0ng VTP hi\u1ec7n nay \u00edt \u0111\u01b0\u1ee3c khuy\u1ebfn kh\u00edch s\u1eed d\u1ee5ng).<\/p>\n<p>Ph\u1ea1m vi ho\u1ea1t \u0111\u1ed9ng c\u1ee7a m\u1ed9t <strong>VLAN<\/strong> \u0111\u01b0\u1ee3c gi\u1edbi h\u1ea1n b\u1edfi <strong>Router<\/strong> ho\u1eb7c c\u00e1c thi\u1ebft b\u1ecb \u0111\u1ecbnh tuy\u1ebfn Layer 3. <strong>VLAN<\/strong> l\u00e0 c\u00f4ng ngh\u1ec7 Layer 2, do \u0111\u00f3, c\u00e1c m\u00e1y t\u00ednh thu\u1ed9c c\u00e1c <strong>VLAN<\/strong> kh\u00e1c nhau kh\u00f4ng th\u1ec3 giao ti\u1ebfp tr\u1ef1c ti\u1ebfp v\u1edbi nhau m\u00e0 c\u1ea7n ph\u1ea3i \u0111i qua m\u1ed9t thi\u1ebft b\u1ecb Layer 3 \u0111\u1ec3 th\u1ef1c hi\u1ec7n \u0111\u1ecbnh tuy\u1ebfn li\u00ean <strong>VLAN<\/strong> (Inter-VLAN Routing).<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Mang-VLAN-duoc-phan-loai-nhu-the-nao\"><\/span>M\u1ea1ng VLAN \u0111\u01b0\u1ee3c ph\u00e2n lo\u1ea1i nh\u01b0 th\u1ebf n\u00e0o?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p><strong>VLAN<\/strong> c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c ph\u00e2n lo\u1ea1i d\u1ef1a tr\u00ean c\u00e1ch c\u00e1c c\u1ed5ng <strong>Switch<\/strong> \u0111\u01b0\u1ee3c g\u00e1n ho\u1eb7c d\u1ef1a tr\u00ean ti\u00eau ch\u00ed t\u1ea1o <strong>VLAN<\/strong>. D\u01b0\u1edbi \u0111\u00e2y l\u00e0 c\u00e1c lo\u1ea1i ph\u1ed5 bi\u1ebfn nh\u1ea5t:<\/p>\n<p><strong>Port-Based VLANs (VLAN D\u1ef1a tr\u00ean C\u1ed5ng):<\/strong><\/p>\n<p>\u0110\u00e2y l\u00e0 ph\u01b0\u01a1ng ph\u00e1p ph\u1ed5 bi\u1ebfn nh\u1ea5t. Ng\u01b0\u1eddi qu\u1ea3n tr\u1ecb g\u00e1n th\u1ee7 c\u00f4ng m\u1ed9t c\u1ed5ng <strong>Switch<\/strong> c\u1ee5 th\u1ec3 v\u00e0o m\u1ed9t <strong>VLAN ID<\/strong> c\u1ee5 th\u1ec3.<\/p>\n<ul>\n<li><strong>\u01afu \u0111i\u1ec3m<\/strong>: D\u1ec5 c\u1ea5u h\u00ecnh, d\u1ec5 qu\u1ea3n l\u00fd.<\/li>\n<li><strong>Nh\u01b0\u1ee3c \u0111i\u1ec3m<\/strong>: Khi ng\u01b0\u1eddi d\u00f9ng di chuy\u1ec3n sang m\u1ed9t c\u1ed5ng kh\u00e1c, qu\u1ea3n tr\u1ecb vi\u00ean ph\u1ea3i thay \u0111\u1ed5i c\u1ea5u h\u00ecnh c\u1ed5ng \u0111\u00f3.<\/li>\n<\/ul>\n<p><strong>MAC-Based VLANs (VLAN D\u1ef1a tr\u00ean \u0110\u1ecba ch\u1ec9 MAC):<\/strong><\/p>\n<p><strong>VLAN<\/strong> \u0111\u01b0\u1ee3c x\u00e1c \u0111\u1ecbnh d\u1ef1a tr\u00ean \u0111\u1ecba ch\u1ec9 MAC c\u1ee7a thi\u1ebft b\u1ecb k\u1ebft n\u1ed1i.<\/p>\n<ul>\n<li><strong>\u01afu \u0111i\u1ec3m<\/strong>: Khi ng\u01b0\u1eddi d\u00f9ng di chuy\u1ec3n \u0111\u1ebfn b\u1ea5t k\u1ef3 c\u1ed5ng <strong>Switch<\/strong> n\u00e0o, <strong>VLAN<\/strong> c\u1ee7a h\u1ecd v\u1eabn \u0111\u01b0\u1ee3c gi\u1eef nguy\u00ean.<\/li>\n<li><strong>Nh\u01b0\u1ee3c \u0111i\u1ec3m<\/strong>: C\u1ea7n duy tr\u00ec m\u1ed9t c\u01a1 s\u1edf d\u1eef li\u1ec7u l\u1edbn \u0111\u1ec3 \u00e1nh x\u1ea1 MAC Address v\u1edbi <strong>VLAN ID<\/strong>, t\u1ed1n t\u00e0i nguy\u00ean x\u1eed l\u00fd tr\u00ean <strong>Switch<\/strong>.<\/li>\n<\/ul>\n<p><strong>Protocol-Based VLANs (VLAN D\u1ef1a tr\u00ean Giao th\u1ee9c):<\/strong><\/p>\n<p><strong>VLAN<\/strong> \u0111\u01b0\u1ee3c x\u00e1c \u0111\u1ecbnh d\u1ef1a tr\u00ean lo\u1ea1i giao th\u1ee9c c\u1ee7a g\u00f3i tin (v\u00ed d\u1ee5: IP, IPX).<\/p>\n<ul>\n<li><strong>\u01afu \u0111i\u1ec3m<\/strong>: C\u00f3 th\u1ec3 nh\u00f3m c\u00e1c thi\u1ebft b\u1ecb s\u1eed d\u1ee5ng c\u00f9ng m\u1ed9t giao th\u1ee9c, h\u1eefu \u00edch trong c\u00e1c m\u1ea1ng \u0111a giao th\u1ee9c.<\/li>\n<li><strong>Nh\u01b0\u1ee3c \u0111i\u1ec3m<\/strong>: \u00cdt \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong m\u1ea1ng hi\u1ec7n \u0111\u1ea1i (ch\u1ee7 y\u1ebfu l\u00e0 IP).<\/li>\n<\/ul>\n<h2><span class=\"ez-toc-section\" id=\"Phan-biet-Access-Port-va-Trunk-Port\"><\/span>Ph\u00e2n bi\u1ec7t Access Port v\u00e0 Trunk Port<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Vi\u1ec7c hi\u1ec3u r\u00f5 hai lo\u1ea1i c\u1ed5ng n\u00e0y l\u00e0 ki\u1ebfn th\u1ee9c n\u1ec1n t\u1ea3ng b\u1eaft bu\u1ed9c khi l\u00e0m vi\u1ec7c v\u1edbi <strong>VLAN<\/strong>.<\/p>\n<table style=\"border-collapse: collapse; width: 100%; margin-bottom: 40px; font-family: Arial, sans-serif; border: 1px solid #dddddd;\">\n<thead>\n<tr>\n<th style=\"background-color: #050a71; color: #ffffff; padding: 12px; text-align: left; border: 1px solid #050a71; font-weight: bold;\">\u0110\u1eb7c \u0111i\u1ec3m<\/th>\n<th style=\"background-color: #050a71; color: #ffffff; padding: 12px; text-align: left; border: 1px solid #050a71; font-weight: bold;\">Access Port<\/th>\n<th style=\"background-color: #050a71; color: #ffffff; padding: 12px; text-align: left; border: 1px solid #050a71; font-weight: bold;\">Trunk Port<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td style=\"padding: 10px; border: 1px solid #dddddd; text-align: left; font-weight: bold;\">Vai tr\u00f2<\/td>\n<td style=\"padding: 10px; border: 1px solid #dddddd; text-align: left;\">K\u1ebft n\u1ed1i v\u1edbi thi\u1ebft b\u1ecb cu\u1ed1i (Host, PC, Server, Printer).<\/td>\n<td style=\"padding: 10px; border: 1px solid #dddddd; text-align: left;\">K\u1ebft n\u1ed1i gi\u1eefa hai Switch ho\u1eb7c gi\u1eefa Switch v\u00e0 Router (Layer 3 Device).<\/td>\n<\/tr>\n<tr>\n<td style=\"padding: 10px; border: 1px solid #dddddd; text-align: left; font-weight: bold;\">VLAN<\/td>\n<td style=\"padding: 10px; border: 1px solid #dddddd; text-align: left;\">Ch\u1ec9 mang l\u01b0u l\u01b0\u1ee3ng c\u1ee7a DUY NH\u1ea4T m\u1ed9t VLAN (l\u00e0 VLAN \u0111\u01b0\u1ee3c g\u00e1n).<\/td>\n<td style=\"padding: 10px; border: 1px solid #dddddd; text-align: left;\">Mang l\u01b0u l\u01b0\u1ee3ng c\u1ee7a NHI\u1ec0U VLAN c\u00f9ng l\u00fac.<\/td>\n<\/tr>\n<tr>\n<td style=\"padding: 10px; border: 1px solid #dddddd; text-align: left; font-weight: bold;\">Tagging<\/td>\n<td style=\"padding: 10px; border: 1px solid #dddddd; text-align: left;\">KH\u00d4NG g\u1eafn th\u1ebb VLAN v\u00e0o Frame khi g\u1eedi ra ngo\u00e0i (Frame \u0111i \u0111\u1ebfn Host kh\u00f4ng c\u00f3 Tag).<\/td>\n<td style=\"padding: 10px; border: 1px solid #dddddd; text-align: left;\">B\u1eaeT BU\u1ed8C g\u1eafn th\u1ebb VLAN Tag (802.1Q) v\u00e0o Frame.<\/td>\n<\/tr>\n<tr>\n<td style=\"padding: 10px; border: 1px solid #dddddd; text-align: left; font-weight: bold;\">L\u01b0u l\u01b0\u1ee3ng<\/td>\n<td style=\"padding: 10px; border: 1px solid #dddddd; text-align: left;\">Ch\u1ec9 l\u01b0u l\u01b0\u1ee3ng Untagged (kh\u00f4ng c\u00f3 Tag).<\/td>\n<td style=\"padding: 10px; border: 1px solid #dddddd; text-align: left;\">L\u01b0u l\u01b0\u1ee3ng Tagged (c\u00f3 Tag) v\u00e0 Untagged (d\u00e0nh cho Native VLAN).<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><strong style=\"color: #555555;\">Access Port<\/strong><span style=\"color: #555555;\"> l\u00e0 c\u1ed5ng nh\u1eadp Frame t\u1eeb m\u00e1y t\u00ednh v\u00e0 g\u00e1n <\/span><strong style=\"color: #555555;\">VLAN ID<\/strong><span style=\"color: #555555;\"> v\u00e0o Frame \u0111\u00f3 (n\u1ebfu Frame \u0111i ra kh\u1ecfi <\/span><strong style=\"color: #555555;\">Switch<\/strong><span style=\"color: #555555;\"> qua Trunk). Ng\u01b0\u1ee3c l\u1ea1i, <\/span><strong style=\"color: #555555;\">Trunk Port<\/strong><span style=\"color: #555555;\"> l\u00e0 \u0111\u01b0\u1eddng cao t\u1ed1c mang t\u1ea5t c\u1ea3 c\u00e1c <\/span><strong style=\"color: #555555;\">VLAN<\/strong><span style=\"color: #555555;\"> qua l\u1ea1i gi\u1eefa c\u00e1c <\/span><strong style=\"color: #555555;\">Switch<\/strong><span style=\"color: #555555;\">. N\u1ebfu <\/span><strong style=\"color: #555555;\">Trunk Port<\/strong><span style=\"color: #555555;\"> b\u1ecb c\u1ea5u h\u00ecnh sai, to\u00e0n b\u1ed9 m\u1ea1ng <\/span><strong style=\"color: #555555;\">VLAN<\/strong><span style=\"color: #555555;\"> c\u00f3 th\u1ec3 b\u1ecb gi\u00e1n \u0111o\u1ea1n, ho\u1eb7c t\u1ec7 h\u01a1n l\u00e0 g\u00e2y ra l\u1ed7i b\u1ea3o m\u1eadt nghi\u00eam tr\u1ecdng nh\u01b0 <\/span><strong style=\"color: #555555;\">VLAN<\/strong><span style=\"color: #555555;\"> hopping.<\/span><\/p>\n<figure id=\"attachment_35204\" aria-describedby=\"caption-attachment-35204\" style=\"width: 800px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-35204\" src=\"https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/10\/VLAN-duoc-phan-loai-nhu-the-nao.jpg\" alt=\"VLAN \u0111\u01b0\u1ee3c ph\u00e2n lo\u1ea1i nh\u01b0 th\u1ebf n\u00e0o\" width=\"800\" height=\"500\" title=\"\" srcset=\"https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/10\/VLAN-duoc-phan-loai-nhu-the-nao.jpg 800w, https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/10\/VLAN-duoc-phan-loai-nhu-the-nao-300x188.jpg 300w, https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/10\/VLAN-duoc-phan-loai-nhu-the-nao-768x480.jpg 768w\" sizes=\"auto, (max-width: 800px) 100vw, 800px\" \/><figcaption id=\"caption-attachment-35204\" class=\"wp-caption-text\">VLAN \u0111\u01b0\u1ee3c ph\u00e2n lo\u1ea1i nh\u01b0 th\u1ebf n\u00e0o<\/figcaption><\/figure>\n<h2><span class=\"ez-toc-section\" id=\"Uu-va-nhuoc-diem-cua-VLAN-la-gi\"><\/span>\u01afu v\u00e0 nh\u01b0\u1ee3c \u0111i\u1ec3m c\u1ee7a VLAN l\u00e0 g\u00ec?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Vi\u1ec7c tri\u1ec3n khai <strong>VLAN<\/strong> mang l\u1ea1i nh\u1eefng l\u1ee3i \u00edch v\u01b0\u1ee3t tr\u1ed9i, nh\u01b0ng c\u0169ng \u0111i k\u00e8m v\u1edbi m\u1ed9t s\u1ed1 th\u00e1ch th\u1ee9c k\u1ef9 thu\u1eadt c\u1ea7n l\u01b0u t\u00e2m.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Uu-diem-vuot-troi-cua-VLAN\"><\/span>\u01afu \u0111i\u1ec3m v\u01b0\u1ee3t tr\u1ed9i c\u1ee7a VLAN<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Vi\u1ec7c tri\u1ec3n khai <strong>VLAN<\/strong> mang l\u1ea1i nh\u1eefng l\u1ee3i \u00edch v\u01b0\u1ee3t tr\u1ed9i<\/p>\n<h4><strong>Gi\u1ea3m thi\u1ec3u T\u1eafc ngh\u1ebdn M\u1ea1ng<\/strong><\/h4>\n<p>B\u1eb1ng c\u00e1ch chia <strong>Broadcast Domain<\/strong> l\u1edbn th\u00e0nh nhi\u1ec1u mi\u1ec1n nh\u1ecf h\u01a1n, <strong>VLAN<\/strong> gi\u1ea3m s\u1ed1 l\u01b0\u1ee3ng thi\u1ebft b\u1ecb nh\u1eadn g\u00f3i tin qu\u1ea3ng b\u00e1, t\u1eeb \u0111\u00f3 gi\u1ea3m l\u01b0u l\u01b0\u1ee3ng kh\u00f4ng c\u1ea7n thi\u1ebft tr\u00ean to\u00e0n b\u1ed9 m\u1ea1ng v\u00e0 t\u0103ng t\u1ed1c \u0111\u1ed9 x\u1eed l\u00fd cho t\u1eebng ph\u00e2n \u0111o\u1ea1n m\u1ea1ng. \u0110i\u1ec1u n\u00e0y \u0111\u1eb7c bi\u1ec7t quan tr\u1ecdng trong c\u00e1c m\u00f4i tr\u01b0\u1eddng c\u00f3 nhi\u1ec1u \u1ee9ng d\u1ee5ng nh\u1ea1y c\u1ea3m v\u1ec1 \u0111\u1ed9 tr\u1ec5 nh\u01b0 <strong>VLAN Voice<\/strong> (Voice over IP).<\/p>\n<h4><strong>T\u0103ng c\u01b0\u1eddng B\u1ea3o m\u1eadt M\u1ea1ng<\/strong><\/h4>\n<p>\u0110\u00e2y l\u00e0 \u01b0u \u0111i\u1ec3m l\u1edbn nh\u1ea5t. Vi\u1ec7c t\u00e1ch bi\u1ec7t c\u00e1c nh\u00f3m ng\u01b0\u1eddi d\u00f9ng kh\u00e1c nhau (v\u00ed d\u1ee5: <strong>VLAN<\/strong> Qu\u1ea3n l\u00fd, <strong>VLAN<\/strong> Kh\u00e1ch, <strong>VLAN<\/strong> Server) \u0111\u1ea3m b\u1ea3o r\u1eb1ng n\u1ebfu m\u1ed9t k\u1ebb t\u1ea5n c\u00f4ng x\u00e2m nh\u1eadp v\u00e0o m\u1ed9t ph\u00e2n \u0111o\u1ea1n m\u1ea1ng (v\u00ed d\u1ee5: m\u1ea1ng <strong>VLAN<\/strong> Kh\u00e1ch), ch\u00fang s\u1ebd kh\u00f4ng th\u1ec3 truy c\u1eadp v\u00e0o c\u00e1c t\u00e0i nguy\u00ean c\u1ee7a c\u00e1c <strong>VLAN<\/strong> kh\u00e1c. K\u1ef9 thu\u1eadt n\u00e0y gi\u00fap c\u00e1ch ly d\u1eef li\u1ec7u nh\u1ea1y c\u1ea3m.<\/p>\n<h4><strong>Qu\u1ea3n l\u00fd Ng\u01b0\u1eddi d\u00f9ng Linh ho\u1ea1t<\/strong><\/h4>\n<p>Ng\u01b0\u1eddi qu\u1ea3n tr\u1ecb c\u00f3 th\u1ec3 d\u1ec5 d\u00e0ng th\u00eam, x\u00f3a ho\u1eb7c di chuy\u1ec3n ng\u01b0\u1eddi d\u00f9ng sang <strong>VLAN<\/strong> m\u1edbi ch\u1ec9 b\u1eb1ng c\u00e1ch thay \u0111\u1ed5i c\u1ea5u h\u00ecnh c\u1ed5ng <strong>Switch<\/strong> m\u00e0 kh\u00f4ng c\u1ea7n thay \u0111\u1ed5i h\u1ec7 th\u1ed1ng c\u00e1p. T\u00ednh linh ho\u1ea1t n\u00e0y gi\u00fap ti\u1ebft ki\u1ec7m th\u1eddi gian v\u00e0 chi ph\u00ed b\u1ea3o tr\u00ec.<\/p>\n<h4><strong>Hi\u1ec7u su\u1ea5t Chi ph\u00ed cao<\/strong><\/h4>\n<p>So v\u1edbi vi\u1ec7c mua nhi\u1ec1u <strong>Switch<\/strong> v\u1eadt l\u00fd ho\u1eb7c <strong>Router<\/strong> \u0111\u1ec3 ph\u00e2n \u0111o\u1ea1n m\u1ea1ng, vi\u1ec7c s\u1eed d\u1ee5ng <strong>VLAN<\/strong> tr\u00ean m\u1ed9t <strong>Switch<\/strong> c\u00f3 kh\u1ea3 n\u0103ng Layer 2\/Layer 3 duy nh\u1ea5t mang l\u1ea1i hi\u1ec7u qu\u1ea3 kinh t\u1ebf cao h\u01a1n nhi\u1ec1u.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Nhuoc-diem-va-thach-thuc-cua-VLAN\"><\/span>Nh\u01b0\u1ee3c \u0111i\u1ec3m v\u00e0 th\u00e1ch th\u1ee9c c\u1ee7a VLAN<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>Vi\u1ec7c tri\u1ec3n khai <strong>VLAN<\/strong> mang l\u1ea1i nh\u1eefng l\u1ee3i \u00edch nh\u01b0ng c\u0169ng \u0111i k\u00e8m v\u1edbi m\u1ed9t s\u1ed1 th\u00e1ch th\u1ee9c<\/p>\n<h4><strong>Ph\u1ee9c t\u1ea1p trong C\u1ea5u h\u00ecnh v\u00e0 Qu\u1ea3n l\u00fd<\/strong><\/h4>\n<p>V\u1edbi s\u1ed1 l\u01b0\u1ee3ng <strong>VLAN<\/strong> l\u1edbn (v\u00ed d\u1ee5: tr\u00ean 50 <strong>VLAN<\/strong>), vi\u1ec7c qu\u1ea3n l\u00fd c\u00e1c <strong>VLAN ID<\/strong>, c\u00e1c c\u1ed5ng <strong>Access Port<\/strong> v\u00e0 c\u00e1c c\u1ed5ng <strong>Trunk Port<\/strong> tr\u00ean nhi\u1ec1u <strong>Switch<\/strong> c\u00f3 th\u1ec3 tr\u1edf n\u00ean ph\u1ee9c t\u1ea1p v\u00e0 d\u1ec5 g\u00e2y ra l\u1ed7i c\u1ea5u h\u00ecnh n\u1ebfu kh\u00f4ng c\u00f3 quy tr\u00ecnh r\u00f5 r\u00e0ng.<\/p>\n<h4><strong>Y\u00eau c\u1ea7u Thi\u1ebft b\u1ecb H\u1ed7 tr\u1ee3<\/strong><\/h4>\n<p>\u0110\u1ec3 s\u1eed d\u1ee5ng <strong>VLAN<\/strong>, b\u1ea1n b\u1eaft bu\u1ed9c ph\u1ea3i c\u00f3 c\u00e1c thi\u1ebft b\u1ecb <strong>Switch<\/strong> h\u1ed7 tr\u1ee3 ti\u00eau chu\u1ea9n <strong>IEEE 802.1Q<\/strong> (Managed Switch). C\u00e1c lo\u1ea1i <strong>Switch<\/strong> c\u01a1 b\u1ea3n (Unmanaged Switch) kh\u00f4ng th\u1ec3 th\u1ef1c hi\u1ec7n ch\u1ee9c n\u0103ng <strong>VLAN<\/strong> Tagging.<\/p>\n<h4><strong>Single Point of Failure (\u0110i\u1ec3m l\u1ed7i \u0110\u01a1n l\u1ebb)<\/strong><\/h4>\n<p>N\u1ebfu m\u1ed9t <strong>Switch<\/strong> ch\u00ednh (Core Switch) b\u1ecb l\u1ed7i, t\u1ea5t c\u1ea3 c\u00e1c <strong>VLAN<\/strong> v\u00e0 c\u00e1c ph\u00e2n \u0111o\u1ea1n m\u1ea1ng k\u1ebft n\u1ed1i v\u1edbi <strong>Switch<\/strong> \u0111\u00f3 s\u1ebd b\u1ecb \u1ea3nh h\u01b0\u1edfng. Vi\u1ec7c thi\u1ebft k\u1ebf d\u1ef1 ph\u00f2ng (Redundancy) l\u00e0 c\u1ea7n thi\u1ebft nh\u01b0ng l\u1ea1i l\u00e0m t\u0103ng \u0111\u1ed9 ph\u1ee9c t\u1ea1p c\u1ee7a h\u1ec7 th\u1ed1ng <strong>VLAN<\/strong>.<\/p>\n<h4><strong>Ph\u1ee5 thu\u1ed9c v\u00e0o Thi\u1ebft b\u1ecb Layer 3<\/strong><\/h4>\n<p>\u0110\u1ec3 giao ti\u1ebfp gi\u1eefa c\u00e1c <strong>VLAN<\/strong> kh\u00e1c nhau, b\u1eaft bu\u1ed9c ph\u1ea3i c\u00f3 thi\u1ebft b\u1ecb \u0111\u1ecbnh tuy\u1ebfn (Router ho\u1eb7c <strong>Switch<\/strong> Layer 3) th\u1ef1c hi\u1ec7n Inter-VLAN Routing. \u0110\u00e2y l\u00e0 m\u1ed9t \u0111i\u1ec3m y\u1ebfu c\u1ee7a c\u00f4ng ngh\u1ec7 <strong>VLAN<\/strong> (Layer 2).<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Ung-dung-cua-mang-VLAN\"><\/span>\u1ee8ng d\u1ee5ng c\u1ee7a m\u1ea1ng VLAN<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Vi\u1ec7c \u00e1p d\u1ee5ng <strong>VLAN<\/strong> kh\u00f4ng ch\u1ec9 l\u00e0 m\u1ed9t gi\u1ea3i ph\u00e1p k\u1ef9 thu\u1eadt m\u00e0 c\u00f2n l\u00e0 m\u1ed9t chi\u1ebfn l\u01b0\u1ee3c kinh doanh gi\u00fap t\u1ed1i \u01b0u h\u00f3a t\u00e0i nguy\u00ean.<\/p>\n<ol>\n<li><strong>Ph\u00e2n t\u00e1ch Ph\u00f2ng ban Doanh nghi\u1ec7p:<\/strong> \u0110\u00e2y l\u00e0 \u1ee9ng d\u1ee5ng ph\u1ed5 bi\u1ebfn nh\u1ea5t.\n<ul>\n<li><strong>VLAN<\/strong> 10: K\u1ebf to\u00e1n (D\u1eef li\u1ec7u t\u00e0i ch\u00ednh nh\u1ea1y c\u1ea3m).<\/li>\n<li><strong>VLAN<\/strong> 20: Kinh doanh\/Marketing (L\u01b0u l\u01b0\u1ee3ng truy c\u1eadp Internet cao, \u00edt nh\u1ea1y c\u1ea3m).<\/li>\n<li><strong>VLAN<\/strong> 30: <strong>VLAN Voice<\/strong> (L\u01b0u l\u01b0\u1ee3ng VoIP, y\u00eau c\u1ea7u \u0111\u1ed9 tr\u1ec5 th\u1ea5p).<\/li>\n<li><strong>VLAN<\/strong> 40: <strong>VLAN<\/strong> Kh\u00e1ch (Guest Network, c\u00e1ch ly ho\u00e0n to\u00e0n v\u1edbi m\u1ea1ng n\u1ed9i b\u1ed9).<\/li>\n<li>B\u1eb1ng c\u00e1ch n\u00e0y, n\u1ebfu l\u01b0u l\u01b0\u1ee3ng Marketing t\u0103ng \u0111\u1ed9t bi\u1ebfn, n\u00f3 s\u1ebd kh\u00f4ng \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn ch\u1ea5t l\u01b0\u1ee3ng cu\u1ed9c g\u1ecdi c\u1ee7a ph\u00f2ng K\u1ebf to\u00e1n.<\/li>\n<\/ul>\n<\/li>\n<li><strong>H\u1ec7 th\u1ed1ng Camera Gi\u00e1m s\u00e1t (IP Camera):<\/strong> C\u00e1c camera an ninh t\u1ea1o ra l\u01b0u l\u01b0\u1ee3ng video li\u00ean t\u1ee5c v\u00e0 kh\u1ed5ng l\u1ed3. Vi\u1ec7c \u0111\u1eb7t t\u1ea5t c\u1ea3 c\u00e1c camera v\u00e0o m\u1ed9t <strong>VLAN<\/strong> ri\u00eang bi\u1ec7t s\u1ebd ng\u0103n ch\u1eb7n l\u01b0u l\u01b0\u1ee3ng n\u00e0y l\u00e0m qu\u00e1 t\u1ea3i m\u1ea1ng d\u1eef li\u1ec7u ch\u00ednh c\u1ee7a nh\u00e2n vi\u00ean.<\/li>\n<li><strong>Trung t\u00e2m D\u1eef li\u1ec7u (Data Center):<\/strong> <strong>VLAN<\/strong> \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 c\u00f4 l\u1eadp c\u00e1c m\u00e1y ch\u1ee7 theo ch\u1ee9c n\u0103ng (Web Servers, Database Servers) v\u00e0 \u00e1p d\u1ee5ng c\u00e1c ch\u00ednh s\u00e1ch b\u1ea3o m\u1eadt kh\u00e1c nhau cho m\u1ed7i nh\u00f3m. \u0110i\u1ec1u n\u00e0y gi\u00fap ng\u0103n ch\u1eb7n s\u1ef1 l\u00e2y lan c\u1ee7a c\u00e1c m\u1ed1i \u0111e d\u1ecda.<\/li>\n<\/ol>\n<figure id=\"attachment_35205\" aria-describedby=\"caption-attachment-35205\" style=\"width: 800px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-35205\" src=\"https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/10\/Ung-dung-cua-mang-VLAN.jpg\" alt=\"\u1ee8ng d\u1ee5ng c\u1ee7a m\u1ea1ng VLAN\" width=\"800\" height=\"500\" title=\"\" srcset=\"https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/10\/Ung-dung-cua-mang-VLAN.jpg 800w, https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/10\/Ung-dung-cua-mang-VLAN-300x188.jpg 300w, https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/10\/Ung-dung-cua-mang-VLAN-768x480.jpg 768w\" sizes=\"auto, (max-width: 800px) 100vw, 800px\" \/><figcaption id=\"caption-attachment-35205\" class=\"wp-caption-text\">\u1ee8ng d\u1ee5ng c\u1ee7a m\u1ea1ng VLAN<\/figcaption><\/figure>\n<h2><span class=\"ez-toc-section\" id=\"Cach-cau-hinh-va-thiet-lap-mang-VLAN\"><\/span>C\u00e1ch c\u1ea5u h\u00ecnh v\u00e0 thi\u1ebft l\u1eadp m\u1ea1ng VLAN<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>\u0110\u1ec3 c\u1ea5u h\u00ecnh v\u00e0 thi\u1ebft l\u1eadp VLAN (Virtual LAN) tr\u00ean switch, b\u1ea1n c\u1ea7n th\u1ef1c hi\u1ec7n 3 b\u01b0\u1edbc ch\u00ednh: t\u1ea1o VLAN, g\u00e1n c\u1ed5ng cho VLAN v\u00e0 c\u1ea5u h\u00ecnh c\u00e1c t\u00ednh n\u0103ng li\u00ean quan n\u1ebfu c\u1ea7n. D\u01b0\u1edbi \u0111\u00e2y l\u00e0 h\u01b0\u1edbng d\u1eabn c\u01a1 b\u1ea3n nh\u1ea5t \u00e1p d\u1ee5ng cho ph\u1ea7n l\u1edbn c\u00e1c d\u00f2ng switch qu\u1ea3n l\u00fd hi\u1ec7n nay.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Buoc-1-Tao-VLAN\"><\/span>B\u01b0\u1edbc 1: T\u1ea1o VLAN<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<ul>\n<li>V\u00e0o ch\u1ebf \u0111\u1ed9 c\u1ea5u h\u00ecnh switch:\n<ul>\n<li><strong><code>enable<\/code><\/strong><\/li>\n<li><strong><code>configure terminal<\/code><\/strong><\/li>\n<\/ul>\n<\/li>\n<li>T\u1ea1o VLAN v\u00e0 \u0111\u1eb7t t\u00ean (v\u00ed d\u1ee5 VLAN 10 cho k\u1ebf to\u00e1n, VLAN 20 cho k\u1ef9 thu\u1eadt):\n<ul>\n<li><strong><code>vlan 10<\/code><\/strong><\/li>\n<li><strong><code>name KETOAN<\/code><\/strong><\/li>\n<li><strong><code>vlan 20<\/code><\/strong><\/li>\n<li><strong><code>name KYTHUAT<\/code><\/strong><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h3><span class=\"ez-toc-section\" id=\"Buoc-2-Gan-cong-vao-VLAN\"><\/span>B\u01b0\u1edbc 2: G\u00e1n c\u1ed5ng v\u00e0o VLAN<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<ul>\n<li>Ch\u1ecdn c\u00e1c c\u1ed5ng c\u1ea7n g\u00e1n v\u00e0o t\u1eebng VLAN:\n<ul>\n<li><strong><code>interface range fa0\/1 - 2<\/code><\/strong><\/li>\n<li><strong><code>switchport mode access<\/code><\/strong><\/li>\n<li><strong><code>switchport access vlan 10<\/code><\/strong> (c\u00e1c c\u1ed5ng thu\u1ed9c VLAN 10)<\/li>\n<\/ul>\n<\/li>\n<li>L\u1eb7p l\u1ea1i th\u00f4ng s\u1ed1 cho VLAN kh\u00e1c n\u1ebfu c\u1ea7n:\n<ul>\n<li><strong><code>interface fa0\/3<\/code><\/strong><\/li>\n<li><strong><code>switchport access vlan 20<\/code><\/strong><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h3><span class=\"ez-toc-section\" id=\"Buoc-3-Kiem-tra-va-luu-cau-hinh\"><\/span>B\u01b0\u1edbc 3: Ki\u1ec3m tra v\u00e0 l\u01b0u c\u1ea5u h\u00ecnh<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<ul>\n<li>Ki\u1ec3m tra l\u1ea1i c\u1ea5u h\u00ecnh VLAN:\n<ul>\n<li><strong><code>show vlan brief<\/code><\/strong><\/li>\n<\/ul>\n<\/li>\n<li>L\u01b0u l\u1ea1i c\u1ea5u h\u00ecnh:\n<ul>\n<li><strong><code>write memory<\/code><\/strong> ho\u1eb7c <strong><code>copy running-config startup-config<\/code><\/strong><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p><strong>L\u01b0u \u00fd th\u00eam:<\/strong><\/p>\n<ul>\n<li>\u0110\u1ec3 c\u00e1c VLAN kh\u00e1c nhau li\u00ean l\u1ea1c \u0111\u01b0\u1ee3c v\u1edbi nhau, c\u1ea7n c\u1ea5u h\u00ecnh Inter-VLAN Routing tr\u00ean thi\u1ebft b\u1ecb Layer 3 (switch Layer 3 ho\u1eb7c router).<\/li>\n<li>N\u1ebfu c\u1ea5u h\u00ecnh cho m\u00f4i tr\u01b0\u1eddng th\u1ef1c t\u1ebf, c\u00f3 th\u1ec3 c\u1ea7n ph\u00e2n lo\u1ea1i th\u00eam c\u00e1c d\u1ea1ng port (access\/trunk), g\u00e1n voice VLAN cho \u0111i\u1ec7n tho\u1ea1i IP ho\u1eb7c c\u1ea5u h\u00ecnh VLAN tr\u00ean c\u00e1c router kh\u00e1c nh\u01b0 Mikrotik, TP-Link v\u1edbi c\u00e1c b\u01b0\u1edbc t\u01b0\u01a1ng t\u1ef1 v\u1ec1 logic.<\/li>\n<\/ul>\n<p>C\u1ea5u h\u00ecnh c\u1ee5 th\u1ec3 c\u00f3 th\u1ec3 s\u1ebd kh\u00e1c \u0111\u00f4i ch\u00fat t\u00f9y thi\u1ebft b\u1ecb, nh\u01b0ng nguy\u00ean t\u1eafc tr\u00ecnh t\u1ef1 thao t\u00e1c t\u01b0\u01a1ng t\u1ef1 cho m\u1ecdi h\u00e3ng switch qu\u1ea3n l\u00fd.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"So-sanh-su-khac-nhau-giua-mang-LAN-va-VLAN\"><\/span>So s\u00e1nh s\u1ef1 kh\u00e1c nhau gi\u1eefa m\u1ea1ng LAN v\u00e0 VLAN<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>M\u1eb7c d\u00f9 c\u00f3 t\u00ean g\u1ecdi t\u01b0\u01a1ng \u0111\u1ed3ng, <strong>m\u1ea1ng LAN<\/strong> v\u00e0 <strong>VLAN<\/strong> \u0111\u1ea1i di\u1ec7n cho hai c\u1ea5p \u0111\u1ed9 ph\u00e2n \u0111o\u1ea1n m\u1ea1ng kh\u00e1c nhau. <a href=\"https:\/\/interdata.vn\/\"><strong>InterData<\/strong><\/a> s\u1ebd gi\u00fap b\u1ea1n hi\u1ec3u r\u00f5 s\u1ef1 kh\u00e1c bi\u1ec7t gi\u00fap b\u1ea1n bi\u1ebft khi n\u00e0o n\u00ean s\u1eed d\u1ee5ng gi\u1ea3i ph\u00e1p n\u00e0o.<\/p>\n<table style=\"border-collapse: collapse; width: 100%; font-family: Arial, sans-serif; border: 1px solid #dddddd;\">\n<thead>\n<tr>\n<th style=\"background-color: #050a71; color: #ffffff; padding: 12px; border: 1px solid #050a71; font-weight: bold; text-align: center;\">\u0110\u1eb7c \u0111i\u1ec3m<\/th>\n<th style=\"background-color: #050a71; color: #ffffff; padding: 12px; border: 1px solid #050a71; font-weight: bold; text-align: center;\">M\u1ea1ng LAN Truy\u1ec1n Th\u1ed1ng (Flat LAN)<\/th>\n<th style=\"background-color: #050a71; color: #ffffff; padding: 12px; border: 1px solid #050a71; font-weight: bold; text-align: center;\">M\u1ea1ng VLAN (Virtual LAN)<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td style=\"padding: 10px; border: 1px solid #dddddd; text-align: left; font-weight: bold;\">Ph\u00e2n \u0111o\u1ea1n<\/td>\n<td style=\"padding: 10px; border: 1px solid #dddddd; text-align: left;\">V\u1eadt l\u00fd<\/td>\n<td style=\"padding: 10px; border: 1px solid #dddddd; text-align: left;\">Logic<\/td>\n<\/tr>\n<tr>\n<td style=\"padding: 10px; border: 1px solid #dddddd; text-align: left; font-weight: bold;\">Broadcast Domain<\/td>\n<td style=\"padding: 10px; border: 1px solid #dddddd; text-align: left;\">Duy nh\u1ea5t, l\u1edbn (B\u1eb1ng to\u00e0n b\u1ed9 m\u1ea1ng LAN).<\/td>\n<td style=\"padding: 10px; border: 1px solid #dddddd; text-align: left;\">Nhi\u1ec1u, nh\u1ecf h\u01a1n (M\u1ed7i VLAN l\u00e0 m\u1ed9t mi\u1ec1n).<\/td>\n<\/tr>\n<tr>\n<td style=\"padding: 10px; border: 1px solid #dddddd; text-align: left; font-weight: bold;\">V\u1ecb Tr\u00ed Thi\u1ebft b\u1ecb<\/td>\n<td style=\"padding: 10px; border: 1px solid #dddddd; text-align: left;\">Ph\u1ee5 thu\u1ed9c v\u00e0o v\u1ecb tr\u00ed v\u1eadt l\u00fd v\u00e0 c\u00e1p m\u1ea1ng.<\/td>\n<td style=\"padding: 10px; border: 1px solid #dddddd; text-align: left;\">\u0110\u1ed9c l\u1eadp v\u1edbi v\u1ecb tr\u00ed v\u1eadt l\u00fd.<\/td>\n<\/tr>\n<tr>\n<td style=\"padding: 10px; border: 1px solid #dddddd; text-align: left; font-weight: bold;\">B\u1ea3o m\u1eadt<\/td>\n<td style=\"padding: 10px; border: 1px solid #dddddd; text-align: left;\">Th\u1ea5p, d\u1ec5 b\u1ecb t\u1ea5n c\u00f4ng n\u1ed9i b\u1ed9.<\/td>\n<td style=\"padding: 10px; border: 1px solid #dddddd; text-align: left;\">Cao, do kh\u1ea3 n\u0103ng c\u00e1ch ly l\u01b0u l\u01b0\u1ee3ng.<\/td>\n<\/tr>\n<tr>\n<td style=\"padding: 10px; border: 1px solid #dddddd; text-align: left; font-weight: bold;\">Kh\u1ea3 n\u0103ng M\u1edf r\u1ed9ng<\/td>\n<td style=\"padding: 10px; border: 1px solid #dddddd; text-align: left;\">Th\u1ea5p, c\u1ea7n th\u00eam ph\u1ea7n c\u1ee9ng (Switch\/Router).<\/td>\n<td style=\"padding: 10px; border: 1px solid #dddddd; text-align: left;\">Cao, ch\u1ec9 c\u1ea7n th\u00eam c\u1ea5u h\u00ecnh VLAN ID.<\/td>\n<\/tr>\n<tr>\n<td style=\"padding: 10px; border: 1px solid #dddddd; text-align: left; font-weight: bold;\">Giao ti\u1ebfp gi\u1eefa c\u00e1c mi\u1ec1n<\/td>\n<td style=\"padding: 10px; border: 1px solid #dddddd; text-align: left;\">Kh\u00f4ng c\u1ea7n \u0111\u1ecbnh tuy\u1ebfn (c\u00f9ng m\u1ed9t mi\u1ec1n).<\/td>\n<td style=\"padding: 10px; border: 1px solid #dddddd; text-align: left;\">B\u1eaft bu\u1ed9c c\u1ea7n \u0111\u1ecbnh tuy\u1ebfn Layer 3 (Inter-VLAN Routing).<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><strong>VLAN<\/strong> l\u00e0 m\u1ed9t l\u1edbp tr\u1eebu t\u01b0\u1ee3ng (abstraction layer) \u0111\u01b0\u1ee3c th\u00eam v\u00e0o tr\u00ean m\u1ea1ng <strong>LAN<\/strong> v\u1eadt l\u00fd, mang l\u1ea1i s\u1ef1 linh ho\u1ea1t v\u00e0 ki\u1ec3m so\u00e1t t\u1ed1t h\u01a1n. Trong m\u1ed9t h\u1ec7 th\u1ed1ng hi\u1ec7n \u0111\u1ea1i, <strong>LAN<\/strong> v\u1eadt l\u00fd ch\u1ec9 l\u00e0 n\u1ec1n t\u1ea3ng, c\u00f2n <strong>VLAN<\/strong> l\u00e0 c\u00f4ng c\u1ee5 t\u1ed5 ch\u1ee9c logic tr\u00ean n\u1ec1n t\u1ea3ng \u0111\u00f3. Do \u0111\u00f3, vi\u1ec7c h\u1ecfi <strong>VLAN l\u00e0 g\u00ec<\/strong> th\u1ef1c ch\u1ea5t l\u00e0 h\u1ecfi v\u1ec1 c\u00f4ng ngh\u1ec7 gi\u00fap m\u1ea1ng <strong>LAN<\/strong> tr\u1edf n\u00ean th\u00f4ng minh v\u00e0 hi\u1ec7u qu\u1ea3 h\u01a1n.<\/p>\n<figure id=\"attachment_35206\" aria-describedby=\"caption-attachment-35206\" style=\"width: 800px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-35206\" src=\"https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/10\/LAN-va-VLAN.jpg\" alt=\"LAN v\u00e0 VLAN\" width=\"800\" height=\"500\" title=\"\" srcset=\"https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/10\/LAN-va-VLAN.jpg 800w, https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/10\/LAN-va-VLAN-300x188.jpg 300w, https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/10\/LAN-va-VLAN-768x480.jpg 768w\" sizes=\"auto, (max-width: 800px) 100vw, 800px\" \/><figcaption id=\"caption-attachment-35206\" class=\"wp-caption-text\">LAN v\u00e0 VLAN<\/figcaption><\/figure>\n<h2><span class=\"ez-toc-section\" id=\"VLAN-Tagging-va-Standard-VLAN\"><\/span>VLAN Tagging v\u00e0 Standard VLAN<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>\u0110\u1ec3 gi\u1ea3i quy\u1ebft v\u1ea5n \u0111\u1ec1 l\u00e0m sao \u0111\u1ec3 nhi\u1ec1u <strong>VLAN<\/strong> c\u00f3 th\u1ec3 truy\u1ec1n qua c\u00f9ng m\u1ed9t \u0111\u01b0\u1eddng d\u00e2y c\u00e1p (Trunk), c\u00e1c t\u1ed5 ch\u1ee9c \u0111\u00e3 ph\u00e1t tri\u1ec3n c\u01a1 ch\u1ebf <strong>VLAN Tagging<\/strong>.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Chuan-IEEE-8021Q-la-gi\"><\/span>Chu\u1ea9n IEEE 802.1Q l\u00e0 g\u00ec?<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p><strong>IEEE 802.1Q<\/strong> l\u00e0 ti\u00eau chu\u1ea9n c\u00f4ng nghi\u1ec7p ph\u1ed5 bi\u1ebfn nh\u1ea5t \u0111\u1ec3 th\u1ef1c hi\u1ec7n <strong>VLAN Tagging<\/strong>.<\/p>\n<p><strong>VLAN Tagging<\/strong> (\u0110\u00f3ng g\u00f3i <strong>VLAN<\/strong>) l\u00e0 qu\u00e1 tr\u00ecnh <strong>Switch<\/strong> th\u00eam m\u1ed9t tr\u01b0\u1eddng th\u00f4ng tin (Tag) v\u00e0o Frame Ethernet khi n\u00f3 truy\u1ec1n qua c\u1ed5ng <strong>Trunk Port<\/strong>. Tr\u01b0\u1eddng n\u00e0y ch\u1ee9a <strong>VLAN ID<\/strong> \u0111\u1ec3 <strong>Switch<\/strong> nh\u1eadn bi\u1ebft (receiving switch) bi\u1ebft Frame n\u00e0y thu\u1ed9c v\u1ec1 <strong>VLAN<\/strong> n\u00e0o.<\/p>\n<p>C\u1ea5u tr\u00fac c\u1ee7a Tag 802.1Q l\u00e0 m\u1ed9t tr\u01b0\u1eddng 4-byte \u0111\u01b0\u1ee3c ch\u00e8n v\u00e0o Frame Ethernet gi\u1eefa \u0111\u1ecba ch\u1ec9 ngu\u1ed3n (Source MAC) v\u00e0 tr\u01b0\u1eddng Length\/Type. Tr\u01b0\u1eddng 4-byte n\u00e0y bao g\u1ed3m c\u00e1c ph\u1ea7n:<\/p>\n<ol>\n<li><strong>TPID (Tag Protocol Identifier):<\/strong> Lu\u00f4n l\u00e0 0x8100, b\u00e1o hi\u1ec7u r\u1eb1ng \u0111\u00e2y l\u00e0 m\u1ed9t Frame c\u00f3 ch\u1ee9a Tag 802.1Q.<\/li>\n<li><strong>TCI (Tag Control Information):<\/strong> Bao g\u1ed3m:\n<ul>\n<li><strong>Priority (3 bit):<\/strong> D\u00f9ng cho ch\u1ea5t l\u01b0\u1ee3ng d\u1ecbch v\u1ee5 (QoS), \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 CoS (Class of Service). R\u1ea5t quan tr\u1ecdng cho <strong>VLAN Voice<\/strong>.<\/li>\n<li><strong>CFI (Canonical Format Indicator &#8211; 1 bit):<\/strong> D\u00f9ng \u0111\u1ec3 t\u01b0\u01a1ng th\u00edch gi\u1eefa c\u00e1c lo\u1ea1i m\u1ea1ng.<\/li>\n<li><strong>VLAN ID (12 bit):<\/strong> X\u00e1c \u0111\u1ecbnh <strong>VLAN<\/strong> m\u00e0 Frame n\u00e0y thu\u1ed9c v\u1ec1.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n<p>Khi <strong>Switch<\/strong> g\u1eedi Frame qua <strong>Trunk Port<\/strong>, n\u00f3 s\u1ebd th\u00eam Tag 802.1Q v\u00e0o. Khi Frame \u0111\u1ebfn <strong>Switch<\/strong> nh\u1eadn, <strong>Switch<\/strong> n\u00e0y s\u1ebd ki\u1ec3m tra Tag, x\u1eed l\u00fd Frame theo <strong>VLAN ID<\/strong> v\u00e0 x\u00f3a Tag ra kh\u1ecfi Frame tr\u01b0\u1edbc khi g\u1eedi Frame \u0111\u00f3 ra <strong>Access Port<\/strong> t\u1edbi m\u00e1y tr\u1ea1m cu\u1ed1i.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Native-VLAN-la-gi\"><\/span>Native VLAN l\u00e0 g\u00ec?<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p><strong>Native VLAN<\/strong> l\u00e0 m\u1ed9t kh\u00e1i ni\u1ec7m quan tr\u1ecdng li\u00ean quan \u0111\u1ebfn chu\u1ea9n <strong>802.1Q<\/strong>.<\/p>\n<p><strong>Native VLAN<\/strong> l\u00e0 <strong>VLAN<\/strong> duy nh\u1ea5t m\u00e0 l\u01b0u l\u01b0\u1ee3ng c\u1ee7a n\u00f3 \u0111\u01b0\u1ee3c truy\u1ec1n qua c\u1ed5ng <strong>Trunk Port<\/strong> d\u01b0\u1edbi d\u1ea1ng <strong>Untagged<\/strong> (kh\u00f4ng \u0111\u01b0\u1ee3c g\u1eafn Tag 802.1Q).<\/p>\n<p>Th\u00f4ng th\u01b0\u1eddng, <strong>VLAN ID<\/strong> 1 (Default <strong>VLAN<\/strong>) \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng l\u00e0m <strong>Native VLAN<\/strong> m\u1eb7c \u0111\u1ecbnh tr\u00ean c\u00e1c <strong>Switch<\/strong>.<\/p>\n<p><strong>T\u00e1c d\u1ee5ng c\u1ee7a Native VLAN:<\/strong><\/p>\n<ul>\n<li><strong>T\u01b0\u01a1ng th\u00edch ng\u01b0\u1ee3c:<\/strong> Cho ph\u00e9p giao ti\u1ebfp v\u1edbi c\u00e1c thi\u1ebft b\u1ecb m\u1ea1ng c\u0169 kh\u00f4ng h\u1ed7 tr\u1ee3 <strong>VLAN<\/strong> Tagging (kh\u00f4ng hi\u1ec3u chu\u1ea9n 802.1Q).<\/li>\n<li><strong>Qu\u1ea3n l\u00fd:<\/strong> L\u01b0u l\u01b0\u1ee3ng \u0111i\u1ec1u khi\u1ec3n c\u1ee7a <strong>Switch<\/strong> (v\u00ed d\u1ee5: CDP, VTP) th\u01b0\u1eddng \u0111\u01b0\u1ee3c g\u1eedi qua <strong>Native VLAN<\/strong> d\u01b0\u1edbi d\u1ea1ng <strong>Untagged<\/strong>.<\/li>\n<\/ul>\n<p><strong>L\u01b0u \u00fd B\u1ea3o m\u1eadt:<\/strong> Vi\u1ec7c c\u1ea5u h\u00ecnh <strong>Native VLAN<\/strong> kh\u00e1c v\u1edbi <strong>VLAN<\/strong> m\u1eb7c \u0111\u1ecbnh (ID 1) l\u00e0 m\u1ed9t bi\u1ec7n ph\u00e1p b\u1ea3o m\u1eadt \u0111\u01b0\u1ee3c khuy\u1ebfn ngh\u1ecb. N\u1ebfu k\u1ebb t\u1ea5n c\u00f4ng g\u1eedi l\u01b0u l\u01b0\u1ee3ng Untagged v\u00e0o <strong>Trunk Port<\/strong>, n\u00f3 s\u1ebd t\u1ef1 \u0111\u1ed9ng \u0111\u01b0\u1ee3c g\u00e1n v\u00e0o <strong>Native VLAN<\/strong>, c\u00f3 th\u1ec3 d\u1eabn \u0111\u1ebfn <strong>VLAN<\/strong> Hopping n\u1ebfu <strong>Native VLAN<\/strong> kh\u00f4ng \u0111\u01b0\u1ee3c ki\u1ec3m so\u00e1t.<\/p>\n<figure id=\"attachment_35207\" aria-describedby=\"caption-attachment-35207\" style=\"width: 800px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-35207\" src=\"https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/10\/VLAN-Tagging-va-Standard-VLAN.jpg\" alt=\"VLAN Tagging v\u00e0 Standard VLAN\" width=\"800\" height=\"500\" title=\"\" srcset=\"https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/10\/VLAN-Tagging-va-Standard-VLAN.jpg 800w, https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/10\/VLAN-Tagging-va-Standard-VLAN-300x188.jpg 300w, https:\/\/interdata.vn\/blog\/wp-content\/uploads\/2025\/10\/VLAN-Tagging-va-Standard-VLAN-768x480.jpg 768w\" sizes=\"auto, (max-width: 800px) 100vw, 800px\" \/><figcaption id=\"caption-attachment-35207\" class=\"wp-caption-text\">VLAN Tagging v\u00e0 Standard VLAN<\/figcaption><\/figure>\n<h2><span class=\"ez-toc-section\" id=\"Cau-hoi-thuong-gap-ve-mang-VLAN-FAQs\"><\/span>C\u00e2u h\u1ecfi th\u01b0\u1eddng g\u1eb7p v\u1ec1 m\u1ea1ng VLAN (FAQs)<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Ph\u1ea7n n\u00e0y s\u1ebd gi\u1ea3i \u0111\u00e1p c\u00e1c th\u1eafc m\u1eafc th\u01b0\u1eddng g\u1eb7p c\u1ee7a sinh vi\u00ean v\u00e0 k\u1ef9 thu\u1eadt vi\u00ean m\u1edbi v\u1ec1 <strong>VLAN<\/strong>.<\/p>\n<h3><span class=\"ez-toc-section\" id=\"VLAN-Voice-la-gi\"><\/span>VLAN Voice l\u00e0 g\u00ec?<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p><strong>VLAN Voice<\/strong> l\u00e0 m\u1ed9t lo\u1ea1i <strong>VLAN<\/strong> \u0111\u01b0\u1ee3c thi\u1ebft k\u1ebf \u0111\u1eb7c bi\u1ec7t \u0111\u1ec3 mang l\u01b0u l\u01b0\u1ee3ng tho\u1ea1i (Voice over IP &#8211; VoIP). N\u00f3 ho\u1ea1t \u0111\u1ed9ng b\u1eb1ng c\u00e1ch t\u00e1ch bi\u1ec7t l\u01b0u l\u01b0\u1ee3ng tho\u1ea1i kh\u1ecfi l\u01b0u l\u01b0\u1ee3ng d\u1eef li\u1ec7u th\u00f4ng th\u01b0\u1eddng.<\/p>\n<p><strong>T\u1ea7m quan tr\u1ecdng:<\/strong> L\u01b0u l\u01b0\u1ee3ng tho\u1ea1i r\u1ea5t nh\u1ea1y c\u1ea3m v\u1edbi \u0111\u1ed9 tr\u1ec5 v\u00e0 m\u1ea5t g\u00f3i (loss). B\u1eb1ng c\u00e1ch \u0111\u1eb7t l\u01b0u l\u01b0\u1ee3ng tho\u1ea1i v\u00e0o <strong>VLAN Voice<\/strong> ri\u00eang, ng\u01b0\u1eddi qu\u1ea3n tr\u1ecb c\u00f3 th\u1ec3 \u00e1p d\u1ee5ng ch\u00ednh s\u00e1ch QoS (Quality of Service) cao nh\u1ea5t (s\u1eed d\u1ee5ng tr\u01b0\u1eddng Priority trong Tag 802.1Q) \u0111\u1ec3 \u0111\u1ea3m b\u1ea3o c\u00e1c g\u00f3i tho\u1ea1i lu\u00f4n \u0111\u01b0\u1ee3c \u01b0u ti\u00ean x\u1eed l\u00fd, mang l\u1ea1i ch\u1ea5t l\u01b0\u1ee3ng cu\u1ed9c g\u1ecdi \u1ed5n \u0111\u1ecbnh v\u00e0 r\u00f5 r\u00e0ng.<\/p>\n<p>M\u1ed9t c\u1ed5ng <strong>Switch<\/strong> k\u1ebft n\u1ed1i v\u1edbi \u0111i\u1ec7n tho\u1ea1i IP th\u01b0\u1eddng \u0111\u01b0\u1ee3c c\u1ea5u h\u00ecnh \u0111\u1ec3 h\u1ed7 tr\u1ee3 c\u1ea3 <strong>VLAN Voice<\/strong> (cho \u0111i\u1ec7n tho\u1ea1i) v\u00e0 m\u1ed9t <strong>VLAN<\/strong> d\u1eef li\u1ec7u (cho m\u00e1y t\u00ednh k\u1ebft n\u1ed1i qua \u0111i\u1ec7n tho\u1ea1i).<\/p>\n<h3><span class=\"ez-toc-section\" id=\"VLAN-va-Subnet-khac-nhau-nhu-the-nao\"><\/span>VLAN v\u00e0 Subnet kh\u00e1c nhau nh\u01b0 th\u1ebf n\u00e0o?<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>\u0110\u00e2y l\u00e0 c\u00e2u h\u1ecfi th\u01b0\u1eddng g\u00e2y nh\u1ea7m l\u1eabn. C\u1ea3 hai \u0111\u1ec1u nh\u1eb1m m\u1ee5c \u0111\u00edch ph\u00e2n \u0111o\u1ea1n m\u1ea1ng, nh\u01b0ng \u1edf c\u00e1c t\u1ea7ng kh\u00e1c nhau:<\/p>\n<ul>\n<li><strong>VLAN:<\/strong> Ho\u1ea1t \u0111\u1ed9ng \u1edf <strong>Layer 2 (Data Link)<\/strong>. N\u00f3 chia nh\u1ecf mi\u1ec1n qu\u1ea3ng b\u00e1 (<strong>Broadcast Domain<\/strong>) v\u00e0 nh\u00f3m c\u00e1c thi\u1ebft b\u1ecb logic l\u1ea1i v\u1edbi nhau.<\/li>\n<li><strong>Subnet (Subnetwork):<\/strong> Ho\u1ea1t \u0111\u1ed9ng \u1edf <strong>Layer 3 (Network)<\/strong>. N\u00f3 chia nh\u1ecf d\u1ea3i \u0111\u1ecba ch\u1ec9 IP (Network Address) th\u00e0nh c\u00e1c m\u1ea1ng con logic nh\u1ecf h\u01a1n.<\/li>\n<\/ul>\n<p><strong>M\u1ed1i quan h\u1ec7:<\/strong> M\u1ed7i <strong>VLAN<\/strong> c\u1ea7n ph\u1ea3i t\u01b0\u01a1ng \u1ee9ng v\u1edbi <strong>DUY NH\u1ea4T<\/strong> m\u1ed9t <strong>Subnet<\/strong>. N\u1ebfu hai thi\u1ebft b\u1ecb thu\u1ed9c c\u00f9ng m\u1ed9t <strong>VLAN<\/strong> nh\u01b0ng l\u1ea1i s\u1eed d\u1ee5ng \u0111\u1ecba ch\u1ec9 IP thu\u1ed9c hai <strong>Subnet<\/strong> kh\u00e1c nhau, ch\u00fang v\u1eabn kh\u00f4ng th\u1ec3 giao ti\u1ebfp tr\u1ef1c ti\u1ebfp \u0111\u01b0\u1ee3c. Ng\u01b0\u1ee3c l\u1ea1i, n\u1ebfu hai thi\u1ebft b\u1ecb thu\u1ed9c hai <strong>VLAN<\/strong> kh\u00e1c nhau nh\u01b0ng l\u1ea1i c\u00f9ng <strong>Subnet<\/strong>, ch\u00fang v\u1eabn b\u1ecb c\u00e1ch ly \u1edf Layer 2. T\u00f3m l\u1ea1i: <strong>VLAN<\/strong> c\u00e1ch ly l\u01b0u l\u01b0\u1ee3ng qu\u1ea3ng b\u00e1, <strong>Subnet<\/strong> c\u00e1ch ly \u0111\u1ecba ch\u1ec9 IP.<\/p>\n<p><strong>VLAN<\/strong> l\u00e0 m\u1ed9t c\u00f4ng ngh\u1ec7 c\u1ed1t l\u00f5i v\u00e0 kh\u00f4ng th\u1ec3 thi\u1ebfu trong m\u1ecdi ki\u1ebfn tr\u00fac m\u1ea1ng hi\u1ec7n \u0111\u1ea1i. Vi\u1ec7c n\u1eafm v\u1eefng VLAN l\u00e0 g\u00ec, t\u1eeb kh\u00e1i ni\u1ec7m m\u1ea1ng LAN \u1ea3o c\u01a1 b\u1ea3n, c\u00e1ch ho\u1ea1t \u0111\u1ed9ng ph\u1ee9c t\u1ea1p c\u1ee7a chu\u1ea9n 802.1Q, vai tr\u00f2 c\u1ee7a Trunk Port v\u00e0 Access Port, cho \u0111\u1ebfn c\u00e1c b\u01b0\u1edbc h\u01b0\u1edbng d\u1eabn c\u1ea5u h\u00ecnh VLAN tr\u00ean thi\u1ebft b\u1ecb Switch Cisco, s\u1ebd gi\u00fap b\u1ea1n qu\u1ea3n tr\u1ecb h\u1ec7 th\u1ed1ng m\u1ea1ng hi\u1ec7u qu\u1ea3 h\u01a1n.<\/p>\n<p>VLAN mang l\u1ea1i l\u1ee3i \u00edch k\u00e9p: v\u1eeba t\u1ed1i \u01b0u hi\u1ec7u su\u1ea5t b\u1eb1ng c\u00e1ch thu nh\u1ecf Broadcast Domain, v\u1eeba t\u0103ng c\u01b0\u1eddng b\u1ea3o m\u1eadt m\u1ea1ng b\u1eb1ng c\u00e1ch c\u00e1ch ly c\u00e1c nh\u00f3m ng\u01b0\u1eddi d\u00f9ng. V\u1edbi s\u1ef1 h\u1ed7 tr\u1ee3 c\u1ee7a c\u00e1c ti\u00eau chu\u1ea9n nh\u01b0 IEEE 802.1Q, VLAN kh\u00f4ng ch\u1ec9 \u0111\u01a1n thu\u1ea7n l\u00e0 ph\u00e2n \u0111o\u1ea1n m\u1ea1ng m\u00e0 l\u00e0 n\u1ec1n t\u1ea3ng cho vi\u1ec7c qu\u1ea3n l\u00fd ch\u1ea5t l\u01b0\u1ee3ng d\u1ecbch v\u1ee5 (QoS) cho c\u00e1c d\u1ecbch v\u1ee5 nh\u1ea1y c\u1ea3m nh\u01b0 VLAN Voice.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>M\u1ea1ng VLAN l\u00e0 k\u1ef9 thu\u1eadt ph\u00e2n \u0111o\u1ea1n m\u1ea1ng LAN v\u1eadt l\u00fd th\u00e0nh nhi\u1ec1u mi\u1ec1n logic nh\u1ecf, gi\u00fap t\u1ed1i \u01b0u hi\u1ec7u su\u1ea5t v\u00e0 t\u0103ng b\u1ea3o m\u1eadt m\u1ea1ng. B\u00e0i vi\u1ebft n\u00e0y c\u1ee7a InterData cung c\u1ea5p ki\u1ebfn th\u1ee9c to\u00e0n di\u1ec7n v\u1ec1 m\u1ea1ng LAN \u1ea3o (VLAN), t\u1eeb l\u00fd thuy\u1ebft c\u01a1 b\u1ea3n (kh\u00e1i ni\u1ec7m, nguy\u00ean l\u00fd ho\u1ea1t \u0111\u1ed9ng) \u0111\u1ebfn c\u00e1c<\/p>\n","protected":false},"author":27,"featured_media":35208,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[151],"tags":[],"class_list":["post-35185","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-mang"],"_links":{"self":[{"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/posts\/35185","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/users\/27"}],"replies":[{"embeddable":true,"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/comments?post=35185"}],"version-history":[{"count":7,"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/posts\/35185\/revisions"}],"predecessor-version":[{"id":35305,"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/posts\/35185\/revisions\/35305"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/media\/35208"}],"wp:attachment":[{"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/media?parent=35185"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/categories?post=35185"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/interdata.vn\/blog\/wp-json\/wp\/v2\/tags?post=35185"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}