{"id":2022,"date":"2025-10-07T14:00:56","date_gmt":"2025-10-07T07:00:56","guid":{"rendered":"https:\/\/kienthucmo.com\/?p=2022"},"modified":"2026-01-21T00:07:20","modified_gmt":"2026-01-20T17:07:20","slug":"tim-hieu-mo-hinh-osi-trong-mang-may-tinh","status":"publish","type":"post","link":"https:\/\/kienthucmo.com\/vi\/tim-hieu-mo-hinh-osi-trong-mang-may-tinh\/","title":{"rendered":"T\u00ecm hi\u1ec3u m\u00f4 h\u00ecnh OSI: C\u00e1ch 7 t\u1ea7ng m\u1ea1ng ph\u1ed1i h\u1ee3p \u0111\u1ec3 Internet v\u1eadn h\u00e0nh tr\u01a1n tru"},"content":{"rendered":"\n

M\u1ea1ng m\u00e1y t\u00ednh l\u00e0 n\u1ec1n t\u1ea3ng k\u1ebft n\u1ed1i th\u1ebf gi\u1edbi s\u1ed1 – t\u1eeb vi\u1ec7c g\u1eedi tin nh\u1eafn, truy c\u1eadp web, \u0111\u1ebfn v\u1eadn h\u00e0nh d\u1ecbch v\u1ee5 \u0111\u00e1m m\u00e2y. \u0110\u1ec3 m\u1ecdi thi\u1ebft b\u1ecb, ph\u1ea7n m\u1ec1m v\u00e0 giao th\u1ee9c kh\u00e1c nhau c\u00f3 th\u1ec3 \u201chi\u1ec3u\u201d nhau, ng\u00e0nh c\u00f4ng nghi\u1ec7p c\u1ea7n m\u1ed9t c\u00e1ch ti\u1ebfp c\u1eadn c\u00f3 c\u1ea5u tr\u00fac \u0111\u1ec3 m\u00f4 t\u1ea3 c\u00e1ch d\u1eef li\u1ec7u \u0111\u01b0\u1ee3c truy\u1ec1n v\u00e0 x\u1eed l\u00fd. M\u00f4 h\u00ecnh OSI (Open Systems Interconnection) ra \u0111\u1eddi nh\u01b0 m\u1ed9t b\u1ea3n \u0111\u1ed3 t\u01b0 duy<\/em> gi\u00fap ph\u00e2n t\u00e1ch v\u00e0 chu\u1ea9n h\u00f3a c\u00e1c ch\u1ee9c n\u0103ng m\u1ea1ng th\u00e0nh c\u00e1c t\u1ea7ng r\u00f5 r\u00e0ng. Trong b\u00e0i vi\u1ebft n\u00e0y, m\u00ecnh v\u00e0 b\u1ea1n s\u1ebd c\u00f9ng kh\u00e1m ph\u00e1 t\u1eebng t\u1ea7ng c\u1ee7a m\u00f4 h\u00ecnh OSI, hi\u1ec3u r\u00f5 ch\u1ee9c n\u0103ng, v\u00ed d\u1ee5 th\u1ef1c t\u1ebf, c\u00e1ch ch\u00fang t\u01b0\u01a1ng t\u00e1c, v\u00e0 vai tr\u00f2 OSI trong h\u1ecdc t\u1eadp v\u00e0 th\u1ef1c t\u1ebf<\/p>\n\n\n

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\"T\u00ecm<\/figure>\n<\/div>\n\n\n

1. T\u1ed5ng quan v\u1ec1 m\u00f4 h\u00ecnh OSI<\/h2>\n\n\n\n

M\u00f4 h\u00ecnh OSI (Open Systems Interconnection) \u0111\u01b0\u1ee3c T\u1ed5 ch\u1ee9c Ti\u00eau chu\u1ea9n h\u00f3a Qu\u1ed1c t\u1ebf \u2013 ISO ph\u00e1t tri\u1ec3n v\u00e0o \u0111\u1ea7u nh\u1eefng n\u0103m 1980 v\u1edbi m\u1ee5c ti\u00eau x\u00e2y d\u1ef1ng m\u1ed9t chu\u1ea9n chung \u0111\u1ec3 m\u00f4 t\u1ea3 c\u00e1ch c\u00e1c h\u1ec7 th\u1ed1ng m\u00e1y t\u00ednh kh\u00e1c nhau giao ti\u1ebfp qua m\u1ea1ng. Tr\u01b0\u1edbc khi c\u00f3 OSI, m\u1ed7i nh\u00e0 s\u1ea3n xu\u1ea5t th\u01b0\u1eddng d\u00f9ng giao th\u1ee9c ri\u00eang, khi\u1ebfn vi\u1ec7c k\u1ebft n\u1ed1i gi\u1eefa c\u00e1c h\u1ec7 th\u1ed1ng tr\u1edf n\u00ean ph\u1ee9c t\u1ea1p v\u00e0 thi\u1ebfu t\u00ednh t\u01b0\u01a1ng th\u00edch. OSI ra \u0111\u1eddi \u0111\u00e3 mang l\u1ea1i m\u1ed9t \u201cng\u00f4n ng\u1eef chung\u201d gi\u00fap t\u1ea5t c\u1ea3 c\u00e1c thi\u1ebft b\u1ecb v\u00e0 ph\u1ea7n m\u1ec1m c\u00f3 th\u1ec3 hi\u1ec3u v\u00e0 trao \u0111\u1ed5i d\u1eef li\u1ec7u v\u1edbi nhau, b\u1ea5t k\u1ec3 ch\u00fang \u0111\u01b0\u1ee3c ph\u00e1t tri\u1ec3n b\u1edfi ai.<\/p>\n\n\n\n

M\u00f4 h\u00ecnh OSI g\u1ed3m 7 t\u1ea7ng, \u0111\u01b0\u1ee3c s\u1eafp x\u1ebfp t\u1eeb t\u1ea7ng v\u1eadt l\u00fd (Physical Layer) \u1edf \u0111\u00e1y \u2013 n\u01a1i d\u1eef li\u1ec7u \u0111\u01b0\u1ee3c truy\u1ec1n d\u01b0\u1edbi d\u1ea1ng t\u00edn hi\u1ec7u \u0111i\u1ec7n ho\u1eb7c s\u00f3ng \u2013 cho \u0111\u1ebfn t\u1ea7ng \u1ee9ng d\u1ee5ng (Application Layer) \u1edf \u0111\u1ec9nh, n\u01a1i c\u00e1c ch\u01b0\u01a1ng tr\u00ecnh ng\u01b0\u1eddi d\u00f9ng nh\u01b0 tr\u00ecnh duy\u1ec7t web hay \u1ee9ng d\u1ee5ng email ho\u1ea1t \u0111\u1ed9ng. M\u1ed7i t\u1ea7ng \u0111\u1ea3m nh\u1eadn m\u1ed9t vai tr\u00f2 c\u1ee5 th\u1ec3 trong qu\u00e1 tr\u00ecnh truy\u1ec1n d\u1eef li\u1ec7u, v\u00e0 giao ti\u1ebfp v\u1edbi t\u1ea7ng tr\u00ean\/d\u01b0\u1edbi qua c\u00e1c giao di\u1ec7n chu\u1ea9n (interface). Nh\u1edd \u0111\u00f3, vi\u1ec7c thi\u1ebft k\u1ebf, n\u00e2ng c\u1ea5p ho\u1eb7c thay \u0111\u1ed5i m\u1ed9t t\u1ea7ng kh\u00f4ng \u1ea3nh h\u01b0\u1edfng tr\u1ef1c ti\u1ebfp \u0111\u1ebfn c\u00e1c t\u1ea7ng kh\u00e1c, gi\u00fap h\u1ec7 th\u1ed1ng linh ho\u1ea1t v\u00e0 d\u1ec5 m\u1edf r\u1ed9ng h\u01a1n.<\/p>\n\n\n\n

V\u00ec sao c\u1ea7n m\u00f4 h\u00ecnh OSI?<\/strong>
N\u1ebfu kh\u00f4ng c\u00f3 m\u1ed9t m\u00f4 h\u00ecnh chu\u1ea9n, vi\u1ec7c x\u00e2y d\u1ef1ng v\u00e0 v\u1eadn h\u00e0nh m\u1ea1ng s\u1ebd tr\u1edf n\u00ean h\u1ed7n lo\u1ea1n: m\u1ed7i c\u00f4ng ty s\u1ebd \u0111\u1ecbnh ngh\u0129a c\u00e1ch truy\u1ec1n d\u1eef li\u1ec7u ri\u00eang, d\u1eabn \u0111\u1ebfn thi\u1ebfu t\u01b0\u01a1ng th\u00edch, kh\u00f3 b\u1ea3o tr\u00ec, v\u00e0 kh\u00f3 ph\u00e1t hi\u1ec7n l\u1ed7i. OSI gi\u1ea3i quy\u1ebft v\u1ea5n \u0111\u1ec1 \u0111\u00f3 b\u1eb1ng c\u00e1ch chia nh\u1ecf h\u1ec7 th\u1ed1ng m\u1ea1ng th\u00e0nh c\u00e1c ph\u1ea7n c\u00f3 ranh gi\u1edbi r\u00f5 r\u00e0ng, gi\u00fap ta:<\/p>\n\n\n\n

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  • Ph\u00e2n chia v\u1ea5n \u0111\u1ec1 th\u00e0nh t\u1eebng ph\u1ea7n nh\u1ecf:<\/strong> D\u1ec5 qu\u1ea3n l\u00fd, d\u1ec5 ph\u00e1t tri\u1ec3n, m\u1ed7i t\u1ea7ng ch\u1ec9 c\u1ea7n t\u1eadp trung v\u00e0o nhi\u1ec7m v\u1ee5 ri\u00eang c\u1ee7a n\u00f3.<\/li>\n\n\n\n
  • \u0110\u01a1n gi\u1ea3n h\u00f3a vi\u1ec7c x\u1eed l\u00fd s\u1ef1 c\u1ed1 (troubleshooting):<\/strong> Khi c\u00f3 l\u1ed7i m\u1ea1ng, ta c\u00f3 th\u1ec3 nhanh ch\u00f3ng x\u00e1c \u0111\u1ecbnh l\u1ed7i n\u1eb1m \u1edf t\u1ea7ng n\u00e0o \u2013 v\u00ed d\u1ee5, l\u1ed7i d\u00e2y c\u00e1p thu\u1ed9c t\u1ea7ng v\u1eadt l\u00fd, c\u00f2n l\u1ed7i IP ho\u1eb7c \u0111\u1ecbnh tuy\u1ebfn n\u1eb1m \u1edf t\u1ea7ng m\u1ea1ng.<\/li>\n\n\n\n
  • H\u1ecdc t\u1eadp v\u00e0 nghi\u00ean c\u1ee9u c\u00f3 h\u1ec7 th\u1ed1ng:<\/strong> Ng\u01b0\u1eddi h\u1ecdc c\u00f3 th\u1ec3 ti\u1ebfp c\u1eadn t\u1eeb kh\u00e1i ni\u1ec7m \u0111\u01a1n gi\u1ea3n (bit, frame, packet) \u0111\u1ebfn ph\u1ee9c t\u1ea1p (session, presentation, application).<\/li>\n\n\n\n
  • Chu\u1ea9n h\u00f3a giao ti\u1ebfp gi\u1eefa c\u00e1c h\u00e3ng:<\/strong> Nh\u1edd OSI, thi\u1ebft b\u1ecb t\u1eeb Cisco, Huawei hay Juniper \u0111\u1ec1u c\u00f3 th\u1ec3 l\u00e0m vi\u1ec7c c\u00f9ng nhau th\u00f4ng qua c\u00e1c giao th\u1ee9c chu\u1ea9n.<\/li>\n<\/ul>\n\n\n
    \n
    \"T\u1ed5ng<\/figure>\n<\/div>\n\n\n

    T\u00f3m l\u1ea1i, m\u00f4 h\u00ecnh OSI kh\u00f4ng ch\u1ec9 l\u00e0 m\u1ed9t kh\u00e1i ni\u1ec7m l\u00fd thuy\u1ebft, m\u00e0 c\u00f2n l\u00e0 b\u1ed9 khung t\u01b0 duy chu\u1ea9n gi\u00fap ch\u00fang ta hi\u1ec3u s\u00e2u c\u00e1ch d\u1eef li\u1ec7u di chuy\u1ec3n trong m\u1ea1ng. Khi n\u1eafm v\u1eefng OSI, m\u00ecnh c\u00f3 th\u1ec3 \u201c\u0111\u1ecdc v\u1ecb\u201d \u0111\u01b0\u1ee3c d\u00f2ng ch\u1ea3y d\u1eef li\u1ec7u, x\u00e1c \u0111\u1ecbnh nhanh v\u1ecb tr\u00ed l\u1ed7i, v\u00e0 thi\u1ebft k\u1ebf h\u1ec7 th\u1ed1ng m\u1ea1ng hi\u1ec7u qu\u1ea3 h\u01a1n.<\/p>\n\n\n\n

    2. Ch\u1ee9c n\u0103ng v\u00e0 vai tr\u00f2 c\u1ee7a t\u1eebng t\u1ea7ng trong m\u00f4 h\u00ecnh OSI<\/h2>\n\n\n\n

    M\u00f4 h\u00ecnh OSI chia h\u1ec7 th\u1ed1ng m\u1ea1ng th\u00e0nh 7 t\u1ea7ng, t\u1eeb v\u1eadt l\u00fd \u0111\u1ebfn \u1ee9ng d\u1ee5ng, m\u1ed7i t\u1ea7ng \u0111\u1ea3m nhi\u1ec7m m\u1ed9t ph\u1ea7n ri\u00eang trong qu\u00e1 tr\u00ecnh truy\u1ec1n v\u00e0 x\u1eed l\u00fd d\u1eef li\u1ec7u. Vi\u1ec7c hi\u1ec3u r\u00f5 t\u1eebng t\u1ea7ng gi\u00fap k\u1ef9 s\u01b0 m\u1ea1ng d\u1ec5 d\u00e0ng x\u00e1c \u0111\u1ecbnh l\u1ed7i, t\u1ed1i \u01b0u hi\u1ec7u n\u0103ng v\u00e0 thi\u1ebft k\u1ebf h\u1ec7 th\u1ed1ng m\u1ea1ng chu\u1ea9n h\u00f3a h\u01a1n. D\u01b0\u1edbi \u0111\u00e2y l\u00e0 chi ti\u1ebft t\u1eebng t\u1ea7ng:<\/p>\n\n\n

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    \"Ch\u1ee9c<\/figure>\n<\/div>\n\n\n

    2.1. T\u1ea7ng V\u1eadt l\u00fd (Physical Layer)<\/h3>\n\n\n\n

    T\u1ea7ng v\u1eadt l\u00fd l\u00e0 n\u1ec1n t\u1ea3ng th\u1ea5p nh\u1ea5t trong m\u00f4 h\u00ecnh OSI, ch\u1ecbu tr\u00e1ch nhi\u1ec7m truy\u1ec1n t\u1ea3i d\u1eef li\u1ec7u d\u1ea1ng bit (0 v\u00e0 1) gi\u1eefa c\u00e1c thi\u1ebft b\u1ecb th\u00f4ng qua m\u00f4i tr\u01b0\u1eddng v\u1eadt l\u00fd nh\u01b0 c\u00e1p \u0111\u1ed3ng, c\u00e1p quang ho\u1eb7c s\u00f3ng v\u00f4 tuy\u1ebfn. N\u00f3i c\u00e1ch kh\u00e1c, \u0111\u00e2y l\u00e0 t\u1ea7ng chuy\u1ec3n \u0111\u1ed5i d\u1eef li\u1ec7u logic th\u00e0nh t\u00edn hi\u1ec7u \u0111i\u1ec7n, quang ho\u1eb7c v\u00f4 tuy\u1ebfn \u0111\u1ec3 c\u00f3 th\u1ec3 truy\u1ec1n \u0111i trong th\u1ef1c t\u1ebf.<\/p>\n\n\n\n

    T\u1ea7ng n\u00e0y kh\u00f4ng quan t\u00e2m \u0111\u1ebfn \u00fd ngh\u0129a c\u1ee7a d\u1eef li\u1ec7u, m\u00e0 ch\u1ec9 t\u1eadp trung v\u00e0o vi\u1ec7c d\u1eef li\u1ec7u c\u00f3 \u0111\u01b0\u1ee3c truy\u1ec1n \u0111i ch\u00ednh x\u00e1c v\u1ec1 m\u1eb7t v\u1eadt l\u00fd hay kh\u00f4ng. N\u00f3 \u0111\u1ecbnh ngh\u0129a c\u00e1c \u0111\u1eb7c t\u00ednh k\u1ef9 thu\u1eadt nh\u01b0:<\/p>\n\n\n\n

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    • \u0110i\u1ec7n \u00e1p v\u00e0 t\u00edn hi\u1ec7u:<\/strong> M\u1ee9c \u0111i\u1ec7n \u00e1p bi\u1ec3u di\u1ec5n bit 0, bit 1; d\u1ea1ng s\u00f3ng t\u00edn hi\u1ec7u; th\u1eddi gian chuy\u1ec3n m\u1ea1ch gi\u1eefa c\u00e1c bit.<\/li>\n\n\n\n
    • T\u1ed1c \u0111\u1ed9 truy\u1ec1n d\u1eef li\u1ec7u (bit rate):<\/strong> X\u00e1c \u0111\u1ecbnh t\u1ed1c \u0111\u1ed9 g\u1eedi d\u1eef li\u1ec7u t\u00ednh theo bit\/gi\u00e2y (bps).<\/li>\n\n\n\n
    • Ki\u1ec3u \u0111\u1ea7u n\u1ed1i v\u00e0 giao di\u1ec7n v\u1eadt l\u00fd:<\/strong> Chu\u1ea9n c\u1eafm nh\u01b0 RJ45, USB, SC\/LC (c\u00e1p quang).<\/li>\n\n\n\n
    • Ki\u1ec3u truy\u1ec1n:<\/strong> Truy\u1ec1n song c\u00f4ng (full-duplex), b\u00e1n song c\u00f4ng (half-duplex) ho\u1eb7c \u0111\u01a1n c\u00f4ng (simplex).<\/li>\n\n\n\n
    • Kho\u1ea3ng c\u00e1ch v\u00e0 suy hao t\u00edn hi\u1ec7u:<\/strong> Quy \u0111\u1ecbnh chi\u1ec1u d\u00e0i t\u1ed1i \u0111a c\u1ee7a c\u00e1p, kh\u1ea3 n\u0103ng ch\u1ed1ng nhi\u1ec5u, v\u00e0 c\u00f4ng su\u1ea5t t\u00edn hi\u1ec7u \u0111\u1ec3 d\u1eef li\u1ec7u kh\u00f4ng b\u1ecb m\u00e9o ho\u1eb7c m\u1ea5t.<\/li>\n<\/ul>\n\n\n\n

      V\u00ed d\u1ee5 th\u1ef1c t\u1ebf:<\/p>\n\n\n\n

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      • C\u00e1p m\u1ea1ng Ethernet Cat5e\/Cat6<\/strong> d\u00f9ng trong m\u1ea1ng LAN.<\/li>\n\n\n\n
      • C\u00e1p quang (Fiber Optic)<\/strong> cho m\u1ea1ng t\u1ed1c \u0111\u1ed9 cao ho\u1eb7c k\u1ebft n\u1ed1i \u0111\u01b0\u1eddng tr\u1ee5c.<\/li>\n\n\n\n
      • Chu\u1ea9n IEEE 802.11 (Wi-Fi)<\/strong> v\u00e0 Bluetooth<\/strong> \u2014 s\u1eed d\u1ee5ng s\u00f3ng radio \u0111\u1ec3 truy\u1ec1n d\u1eef li\u1ec7u m\u00e0 kh\u00f4ng c\u1ea7n d\u00e2y c\u00e1p.<\/li>\n<\/ul>\n\n\n\n

        Thi\u1ebft b\u1ecb ho\u1ea1t \u0111\u1ed9ng \u1edf t\u1ea7ng v\u1eadt l\u00fd<\/strong> g\u1ed3m c\u00f3:<\/p>\n\n\n\n

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        • Hub:<\/strong> truy\u1ec1n t\u00edn hi\u1ec7u \u0111\u1ebfn t\u1ea5t c\u1ea3 c\u00e1c c\u1ed5ng kh\u00e1c m\u00e0 kh\u00f4ng x\u1eed l\u00fd n\u1ed9i dung d\u1eef li\u1ec7u.<\/li>\n\n\n\n
        • Repeater:<\/strong> khu\u1ebfch \u0111\u1ea1i t\u00edn hi\u1ec7u \u0111\u1ec3 m\u1edf r\u1ed9ng ph\u1ea1m vi truy\u1ec1n.<\/li>\n\n\n\n
        • Modem:<\/strong> chuy\u1ec3n \u0111\u1ed5i t\u00edn hi\u1ec7u s\u1ed1 th\u00e0nh t\u00edn hi\u1ec7u t\u01b0\u01a1ng t\u1ef1 (v\u00e0 ng\u01b0\u1ee3c l\u1ea1i) \u0111\u1ec3 truy\u1ec1n qua \u0111\u01b0\u1eddng \u0111i\u1ec7n tho\u1ea1i ho\u1eb7c s\u00f3ng.<\/li>\n<\/ul>\n\n\n\n

          L\u01b0u \u00fd:<\/strong> Khi m\u1ea1ng g\u1eb7p s\u1ef1 c\u1ed1 nh\u01b0 m\u1ea5t k\u1ebft n\u1ed1i, nhi\u1ec5u \u0111i\u1ec7n t\u1eeb, t\u00edn hi\u1ec7u y\u1ebfu ho\u1eb7c l\u1ed7i bit cao (bit error rate), k\u1ef9 s\u01b0 m\u1ea1ng th\u01b0\u1eddng b\u1eaft \u0111\u1ea7u ki\u1ec3m tra t\u1eeb t\u1ea7ng v\u1eadt l\u00fd \u2014 bao g\u1ed3m c\u00e1p, \u0111\u1ea7u n\u1ed1i, card m\u1ea1ng (NIC), ho\u1eb7c thi\u1ebft b\u1ecb trung gian.<\/p>\n\n\n\n

          2.2. T\u1ea7ng Li\u00ean k\u1ebft D\u1eef li\u1ec7u (Data Link Layer)<\/h3>\n\n\n\n

          T\u1ea7ng Li\u00ean k\u1ebft D\u1eef li\u1ec7u<\/strong> l\u00e0 t\u1ea7ng th\u1ee9 hai trong m\u00f4 h\u00ecnh OSI, \u0111\u00f3ng vai tr\u00f2 trung gian gi\u1eefa t\u1ea7ng V\u1eadt l\u00fd (Physical) v\u00e0 t\u1ea7ng M\u1ea1ng (Network). N\u1ebfu t\u1ea7ng v\u1eadt l\u00fd ch\u1ecbu tr\u00e1ch nhi\u1ec7m truy\u1ec1n bit th\u00f4, th\u00ec t\u1ea7ng li\u00ean k\u1ebft d\u1eef li\u1ec7u \u0111\u1ea3m b\u1ea3o c\u00e1c bit n\u00e0y \u0111\u01b0\u1ee3c gom th\u00e0nh kh\u1ed1i c\u00f3 ngh\u0129a \u2014 g\u1ecdi l\u00e0 \u201cframe\u201d \u2014 v\u00e0 \u0111\u01b0\u1ee3c truy\u1ec1n m\u1ed9t c\u00e1ch tin c\u1eady trong c\u00f9ng m\u1ed9t m\u1ea1ng c\u1ee5c b\u1ed9 (LAN).<\/p>\n\n\n

          \n
          \"T\u1ea7ng<\/figure>\n<\/div>\n\n\n

          T\u1ea7ng n\u00e0y c\u00f3 m\u1ed9t s\u1ed1 nhi\u1ec7m v\u1ee5 ch\u00ednh sau:<\/p>\n\n\n\n

            \n
          • \u0110\u00f3ng g\u00f3i d\u1eef li\u1ec7u th\u00e0nh frame:<\/strong> M\u1ed7i frame bao g\u1ed3m ph\u1ea7n header (ch\u1ee9a \u0111\u1ecba ch\u1ec9 MAC ngu\u1ed3n v\u00e0 \u0111\u00edch), d\u1eef li\u1ec7u, v\u00e0 trailer (ch\u1ee9a m\u00e3 ki\u1ec3m tra l\u1ed7i CRC).<\/li>\n\n\n\n
          • Ki\u1ec3m tra v\u00e0 ph\u00e1t hi\u1ec7n l\u1ed7i:<\/strong> D\u00f9ng Cyclic Redundancy Check (CRC) \u0111\u1ec3 ph\u00e1t hi\u1ec7n l\u1ed7i trong qu\u00e1 tr\u00ecnh truy\u1ec1n; n\u1ebfu ph\u00e1t hi\u1ec7n l\u1ed7i, frame s\u1ebd b\u1ecb lo\u1ea1i b\u1ecf ho\u1eb7c y\u00eau c\u1ea7u g\u1eedi l\u1ea1i.<\/li>\n\n\n\n
          • \u0110i\u1ec1u khi\u1ec3n truy c\u1eadp \u0111\u01b0\u1eddng truy\u1ec1n (MAC \u2013 Media Access Control):<\/strong> X\u00e1c \u0111\u1ecbnh thi\u1ebft b\u1ecb n\u00e0o \u0111\u01b0\u1ee3c ph\u00e9p truy\u1ec1n d\u1eef li\u1ec7u t\u1ea1i m\u1ed9t th\u1eddi \u0111i\u1ec3m, gi\u00fap tr\u00e1nh va ch\u1ea1m t\u00edn hi\u1ec7u trong m\u1ea1ng.<\/li>\n\n\n\n
          • Qu\u1ea3n l\u00fd \u0111\u1ecba ch\u1ec9 v\u1eadt l\u00fd:<\/strong> S\u1eed d\u1ee5ng MAC address \u0111\u1ec3 \u0111\u1ecbnh danh duy nh\u1ea5t t\u1eebng thi\u1ebft b\u1ecb trong c\u00f9ng m\u1ed9t m\u1ea1ng LAN.<\/li>\n<\/ul>\n\n\n\n

            Giao th\u1ee9c ti\u00eau bi\u1ec3u:<\/strong><\/p>\n\n\n\n

              \n
            • Ethernet (IEEE 802.3):<\/strong> Chu\u1ea9n ph\u1ed5 bi\u1ebfn nh\u1ea5t trong m\u1ea1ng LAN c\u00f3 d\u00e2y.<\/li>\n\n\n\n
            • PPP (Point-to-Point Protocol):<\/strong> D\u00f9ng cho k\u1ebft n\u1ed1i tr\u1ef1c ti\u1ebfp gi\u1eefa hai thi\u1ebft b\u1ecb (v\u00ed d\u1ee5: k\u1ebft n\u1ed1i modem \u2013 router).<\/li>\n\n\n\n
            • ARP (Address Resolution Protocol):<\/strong> D\u1ecbch \u0111\u1ecba ch\u1ec9 IP (logic) sang \u0111\u1ecba ch\u1ec9 MAC (v\u1eadt l\u00fd), ho\u1ea1t \u0111\u1ed9ng gi\u1eefa t\u1ea7ng 2 v\u00e0 t\u1ea7ng 3.<\/li>\n<\/ul>\n\n\n\n

              Thi\u1ebft b\u1ecb ho\u1ea1t \u0111\u1ed9ng \u1edf t\u1ea7ng n\u00e0y:<\/strong><\/p>\n\n\n\n

                \n
              • Switch:<\/strong> \u0110\u1ecdc \u0111\u1ecba ch\u1ec9 MAC \u0111\u1ec3 chuy\u1ec3n frame \u0111\u1ebfn \u0111\u00fang c\u1ed5ng \u0111\u00edch.<\/li>\n\n\n\n
              • Bridge:<\/strong> K\u1ebft n\u1ed1i v\u00e0 l\u1ecdc d\u1eef li\u1ec7u gi\u1eefa hai m\u1ea1ng LAN nh\u1ecf, gi\u00fap gi\u1ea3m t\u1eafc ngh\u1ebdn.<\/li>\n<\/ul>\n\n\n\n

                V\u00ed d\u1ee5 th\u1ef1c t\u1ebf:<\/strong>
                Khi m\u00e1y t\u00ednh A g\u1eedi d\u1eef li\u1ec7u \u0111\u1ebfn m\u00e1y t\u00ednh B trong c\u00f9ng m\u1ea1ng LAN, t\u1ea7ng Li\u00ean k\u1ebft D\u1eef li\u1ec7u c\u1ee7a A s\u1ebd th\u00eam MAC \u0111\u00edch v\u00e0 MAC ngu\u1ed3n v\u00e0o frame, c\u00f9ng v\u1edbi m\u00e3 CRC \u0111\u1ec3 ph\u00e1t hi\u1ec7n l\u1ed7i. Switch trong m\u1ea1ng s\u1ebd \u0111\u1ecdc \u0111\u1ecba ch\u1ec9 MAC v\u00e0 g\u1eedi frame \u0111\u1ebfn \u0111\u00fang thi\u1ebft b\u1ecb nh\u1eadn.<\/p>\n\n\n\n

                T\u1ea7ng Li\u00ean k\u1ebft D\u1eef li\u1ec7u gi\u1ed1ng nh\u01b0 m\u1ed9t \u201cng\u01b0\u1eddi \u0111i\u1ec1u ph\u1ed1i giao th\u00f4ng\u201d trong m\u1ea1ng LAN \u2014 n\u00f3 \u0111\u1ea3m b\u1ea3o d\u1eef li\u1ec7u \u0111i \u0111\u00fang h\u01b0\u1edbng, kh\u00f4ng b\u1ecb va ch\u1ea1m, v\u00e0 \u0111\u01b0\u1ee3c truy\u1ec1n \u0111i \u1ed5n \u0111\u1ecbnh, \u0111\u00e1ng tin c\u1eady trong ph\u1ea1m vi c\u1ee5c b\u1ed9 tr\u01b0\u1edbc khi \u0111\u1ebfn t\u1ea7ng m\u1ea1ng \u0111\u1ec3 \u0111\u1ecbnh tuy\u1ebfn ra ngo\u00e0i.<\/p>\n\n\n\n

                2.3. T\u1ea7ng M\u1ea1ng (Network Layer)<\/h3>\n\n\n\n

                T\u1ea7ng M\u1ea1ng l\u00e0 t\u1ea7ng th\u1ee9 ba trong m\u00f4 h\u00ecnh OSI<\/strong>, ch\u1ecbu tr\u00e1ch nhi\u1ec7m \u0111\u1ecbnh tuy\u1ebfn (routing) v\u00e0 chuy\u1ec3n ti\u1ebfp (forwarding) g\u00f3i tin t\u1eeb ngu\u1ed3n \u0111\u1ebfn \u0111\u00edch, ngay c\u1ea3 khi hai thi\u1ebft b\u1ecb kh\u00f4ng n\u1eb1m trong c\u00f9ng m\u1ed9t m\u1ea1ng c\u1ee5c b\u1ed9. \u0110\u00e2y l\u00e0 t\u1ea7ng \u0111\u1ea7u ti\u00ean cho ph\u00e9p truy\u1ec1n th\u00f4ng \u0111a m\u1ea1ng (internetworking) \u2014 n\u1ec1n t\u1ea3ng c\u1ee7a Internet ng\u00e0y nay.<\/p>\n\n\n

                \n
                \"T\u1ea7ng<\/figure>\n<\/div>\n\n\n

                Nhi\u1ec7m v\u1ee5 ch\u00ednh c\u1ee7a t\u1ea7ng n\u00e0y g\u1ed3m:<\/p>\n\n\n\n

                  \n
                • \u0110\u1ecbnh \u0111\u1ecba ch\u1ec9 logic:<\/strong> S\u1eed d\u1ee5ng \u0111\u1ecba ch\u1ec9 IP (Internet Protocol) \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh v\u1ecb tr\u00ed thi\u1ebft b\u1ecb trong to\u00e0n b\u1ed9 h\u1ec7 th\u1ed1ng m\u1ea1ng, kh\u00e1c v\u1edbi \u0111\u1ecba ch\u1ec9 MAC (ch\u1ec9 d\u00f9ng trong LAN).<\/li>\n\n\n\n
                • \u0110\u1ecbnh tuy\u1ebfn (Routing):<\/strong> Quy\u1ebft \u0111\u1ecbnh \u0111\u01b0\u1eddng \u0111i t\u1ed1i \u01b0u cho g\u00f3i tin th\u00f4ng qua nhi\u1ec1u router. Vi\u1ec7c n\u00e0y d\u1ef1a tr\u00ean b\u1ea3ng \u0111\u1ecbnh tuy\u1ebfn (routing table) v\u00e0 c\u00e1c thu\u1eadt to\u00e1n nh\u01b0 Dijkstra, Bellman-Ford.<\/li>\n\n\n\n
                • Ph\u00e2n m\u1ea3nh v\u00e0 t\u00e1i l\u1eafp r\u00e1p (Fragmentation & Reassembly):<\/strong> Khi g\u00f3i tin qu\u00e1 l\u1edbn so v\u1edbi k\u00edch th\u01b0\u1edbc MTU (Maximum Transmission Unit) c\u1ee7a \u0111\u01b0\u1eddng truy\u1ec1n, t\u1ea7ng m\u1ea1ng s\u1ebd chia nh\u1ecf g\u00f3i tin r\u1ed3i gh\u00e9p l\u1ea1i \u1edf ph\u00eda nh\u1eadn.<\/li>\n\n\n\n
                • Ki\u1ec3m so\u00e1t l\u01b0u l\u01b0\u1ee3ng v\u00e0 ngh\u1ebdn m\u1ea1ng:<\/strong> Qu\u1ea3n l\u00fd t\u1ed1c \u0111\u1ed9 g\u1eedi g\u00f3i tin \u0111\u1ec3 tr\u00e1nh t\u1eafc ngh\u1ebdn, \u0111\u1ea3m b\u1ea3o m\u1ea1ng ho\u1ea1t \u0111\u1ed9ng \u1ed5n \u0111\u1ecbnh.<\/li>\n<\/ul>\n\n\n\n

                  Giao th\u1ee9c ti\u00eau bi\u1ec3u:<\/strong><\/p>\n\n\n\n

                    \n
                  • IPv4 v\u00e0 IPv6:<\/strong> Hai phi\u00ean b\u1ea3n c\u1ee7a giao th\u1ee9c Internet Protocol, x\u00e1c \u0111\u1ecbnh c\u00e1ch \u0111\u00e1nh \u0111\u1ecba ch\u1ec9 v\u00e0 chuy\u1ec3n ti\u1ebfp g\u00f3i tin.<\/li>\n\n\n\n
                  • ICMP (Internet Control Message Protocol):<\/strong> D\u00f9ng \u0111\u1ec3 ch\u1ea9n \u0111o\u00e1n v\u00e0 b\u00e1o l\u1ed7i (v\u00ed d\u1ee5: l\u1ec7nh ping<\/em>).<\/li>\n\n\n\n
                  • Routing protocols:<\/strong> OSPF, RIP, BGP<\/strong> \u2013 gi\u00fap c\u00e1c router trao \u0111\u1ed5i th\u00f4ng tin v\u00e0 x\u00e2y d\u1ef1ng b\u1ea3ng \u0111\u1ecbnh tuy\u1ebfn t\u1ef1 \u0111\u1ed9ng.<\/li>\n<\/ul>\n\n\n\n

                    Thi\u1ebft b\u1ecb ho\u1ea1t \u0111\u1ed9ng \u1edf t\u1ea7ng n\u00e0y:<\/strong><\/p>\n\n\n\n

                      \n
                    • Router:<\/strong> L\u00e0 thi\u1ebft b\u1ecb \u0111\u1eb7c tr\u01b0ng c\u1ee7a t\u1ea7ng m\u1ea1ng, ch\u1ecbu tr\u00e1ch nhi\u1ec7m \u0111\u1ecbnh tuy\u1ebfn v\u00e0 chuy\u1ec3n g\u00f3i tin gi\u1eefa c\u00e1c m\u1ea1ng kh\u00e1c nhau (LAN \u2194 WAN, ho\u1eb7c gi\u1eefa hai subnet).<\/li>\n<\/ul>\n\n\n\n

                      V\u00ed d\u1ee5 minh h\u1ecda:<\/strong>
                      Gi\u1ea3 s\u1eed m\u00e1y t\u00ednh c\u1ee7a b\u1ea1n trong m\u1ea1ng n\u1ed9i b\u1ed9 (192.168.1.0\/24) g\u1eedi y\u00eau c\u1ea7u \u0111\u1ebfn m\u1ed9t m\u00e1y ch\u1ee7 \u1edf Internet. Router s\u1ebd nh\u1eadn g\u00f3i tin, tra b\u1ea3ng \u0111\u1ecbnh tuy\u1ebfn \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1eddng \u0111i ti\u1ebfp theo, r\u1ed3i chuy\u1ec3n ti\u1ebfp qua c\u00e1c router trung gian cho \u0111\u1ebfn khi \u0111\u1ebfn \u0111\u00edch.<\/p>\n\n\n\n

                      T\u1ea7ng M\u1ea1ng l\u00e0 \u201cb\u1ed9 n\u00e3o \u0111\u1ecbnh h\u01b0\u1edbng\u201d c\u1ee7a h\u1ec7 th\u1ed1ng m\u1ea1ng \u2014 n\u00f3 gi\u00fap d\u1eef li\u1ec7u bi\u1ebft \u0111i \u0111\u00e2u, \u0111i b\u1eb1ng c\u00e1ch n\u00e0o, v\u00e0 \u0111\u1ea3m b\u1ea3o g\u00f3i tin \u0111\u01b0\u1ee3c chuy\u1ec3n t\u1eeb ngu\u1ed3n \u0111\u1ebfn \u0111\u00edch qua nhi\u1ec1u m\u00f4i tr\u01b0\u1eddng m\u1ea1ng kh\u00e1c nhau m\u1ed9t c\u00e1ch hi\u1ec7u qu\u1ea3.<\/p>\n\n\n\n

                      2.4. T\u1ea7ng Giao v\u1eadn (Transport Layer)<\/h3>\n\n\n\n

                      T\u1ea7ng Giao v\u1eadn l\u00e0 t\u1ea7ng th\u1ee9 t\u01b0 trong m\u00f4 h\u00ecnh OSI<\/strong>, ch\u1ecbu tr\u00e1ch nhi\u1ec7m truy\u1ec1n d\u1eef li\u1ec7u gi\u1eefa hai \u1ee9ng d\u1ee5ng \u0111\u1ea7u cu\u1ed1i (end-to-end). N\u1ebfu t\u1ea7ng M\u1ea1ng \u0111\u1ea3m b\u1ea3o g\u00f3i tin \u0111\u1ebfn \u0111\u00fang thi\u1ebft b\u1ecb, th\u00ec t\u1ea7ng Giao v\u1eadn \u0111\u1ea3m b\u1ea3o d\u1eef li\u1ec7u \u0111\u1ebfn \u0111\u00fang ch\u01b0\u01a1ng tr\u00ecnh ho\u1eb7c d\u1ecbch v\u1ee5 tr\u00ean thi\u1ebft b\u1ecb \u0111\u00f3, theo \u0111\u00fang th\u1ee9 t\u1ef1 v\u00e0 kh\u00f4ng b\u1ecb l\u1ed7i.<\/p>\n\n\n

                      \n
                      \"T\u1ea7ng<\/figure>\n<\/div>\n\n\n

                      Ch\u1ee9c n\u0103ng ch\u00ednh c\u1ee7a t\u1ea7ng n\u00e0y g\u1ed3m:<\/p>\n\n\n\n

                        \n
                      • \u0110\u1ea3m b\u1ea3o \u0111\u1ed9 tin c\u1eady:<\/strong> V\u1edbi c\u00e1c giao th\u1ee9c nh\u01b0 TCP (Transmission Control Protocol), t\u1ea7ng giao v\u1eadn s\u1eed d\u1ee5ng c\u01a1 ch\u1ebf ACK (Acknowledgment) v\u00e0 retransmission (g\u1eedi l\u1ea1i khi m\u1ea5t g\u00f3i) \u0111\u1ec3 \u0111\u1ea3m b\u1ea3o d\u1eef li\u1ec7u \u0111\u1ebfn n\u01a1i an to\u00e0n, \u0111\u1ea7y \u0111\u1ee7.<\/li>\n\n\n\n
                      • Ph\u00e2n \u0111o\u1ea1n v\u00e0 t\u00e1i h\u1ee3p d\u1eef li\u1ec7u:<\/strong> D\u1eef li\u1ec7u t\u1eeb \u1ee9ng d\u1ee5ng c\u00f3 th\u1ec3 r\u1ea5t l\u1edbn, n\u00ean t\u1ea7ng n\u00e0y s\u1ebd chia nh\u1ecf th\u00e0nh c\u00e1c segment tr\u01b0\u1edbc khi g\u1eedi, r\u1ed3i gh\u00e9p l\u1ea1i theo \u0111\u00fang th\u1ee9 t\u1ef1 \u1edf b\u00ean nh\u1eadn.<\/li>\n\n\n\n
                      • Ki\u1ec3m so\u00e1t lu\u1ed3ng (Flow Control):<\/strong> Gi\u00fap c\u00e2n b\u1eb1ng t\u1ed1c \u0111\u1ed9 g\u1eedi \u2013 nh\u1eadn gi\u1eefa hai thi\u1ebft b\u1ecb \u0111\u1ec3 tr\u00e1nh t\u00ecnh tr\u1ea1ng qu\u00e1 t\u1ea3i ho\u1eb7c ngh\u1ebdn d\u1eef li\u1ec7u.<\/li>\n\n\n\n
                      • Ki\u1ec3m so\u00e1t l\u1ed7i:<\/strong> Ph\u00e1t hi\u1ec7n l\u1ed7i trong qu\u00e1 tr\u00ecnh truy\u1ec1n nh\u1edd checksum v\u00e0 c\u01a1 ch\u1ebf x\u00e1c nh\u1eadn g\u00f3i tin.<\/li>\n\n\n\n
                      • Multiplexing (\u0111a lu\u1ed3ng):<\/strong> Ph\u00e2n bi\u1ec7t c\u00e1c \u1ee9ng d\u1ee5ng kh\u00e1c nhau th\u00f4ng qua s\u1ed1 c\u1ed5ng (port number) \u2014 v\u00ed d\u1ee5: c\u1ed5ng 80 cho HTTP, 443 cho HTTPS, 25 cho SMTP.<\/li>\n<\/ul>\n\n\n\n

                        Giao th\u1ee9c ti\u00eau bi\u1ec3u:<\/strong><\/p>\n\n\n\n

                          \n
                        • TCP (Transmission Control Protocol):<\/strong> \u0110\u1ea3m b\u1ea3o truy\u1ec1n tin c\u1eady, c\u00f3 ki\u1ec3m so\u00e1t th\u1ee9 t\u1ef1 v\u00e0 x\u00e1c nh\u1eadn. Th\u00edch h\u1ee3p cho c\u00e1c \u1ee9ng d\u1ee5ng c\u1ea7n \u0111\u1ed9 ch\u00ednh x\u00e1c cao nh\u01b0 web, email, FTP.<\/li>\n\n\n\n
                        • UDP (User Datagram Protocol):<\/strong> Kh\u00f4ng \u0111\u1ea3m b\u1ea3o \u0111\u1ed9 tin c\u1eady, kh\u00f4ng ki\u1ec3m so\u00e1t th\u1ee9 t\u1ef1, nh\u01b0ng nhanh v\u00e0 nh\u1eb9. Ph\u00f9 h\u1ee3p cho c\u00e1c \u1ee9ng d\u1ee5ng th\u1eddi gian th\u1ef1c nh\u01b0 game online, video streaming, ho\u1eb7c VoIP.<\/li>\n<\/ul>\n\n\n\n

                          V\u00ed d\u1ee5 th\u1ef1c t\u1ebf:<\/strong>
                          Khi b\u1ea1n m\u1edf tr\u00ecnh duy\u1ec7t v\u00e0 truy c\u1eadp m\u1ed9t website, t\u1ea7ng Giao v\u1eadn s\u1eed d\u1ee5ng TCP<\/strong> \u0111\u1ec3 thi\u1ebft l\u1eadp k\u1ebft n\u1ed1i ba b\u01b0\u1edbc (three-way handshake<\/em>), \u0111\u1ea3m b\u1ea3o d\u1eef li\u1ec7u trang web \u0111\u01b0\u1ee3c g\u1eedi \u0111\u1ebfn tr\u00ecnh duy\u1ec7t \u0111\u00fang th\u1ee9 t\u1ef1 v\u00e0 \u0111\u1ea7y \u0111\u1ee7.<\/p>\n\n\n\n

                          T\u1ea7ng Giao v\u1eadn l\u00e0 \u201cng\u01b0\u1eddi v\u1eadn chuy\u1ec3n \u0111\u00e1ng tin c\u1eady\u201d trong m\u00f4 h\u00ecnh OSI \u2014 \u0111\u1ea3m b\u1ea3o d\u1eef li\u1ec7u kh\u00f4ng ch\u1ec9 \u0111\u1ebfn n\u01a1i, m\u00e0 c\u00f2n \u0111\u1ebfn \u0111\u00fang c\u00e1ch, \u0111\u00fang l\u00fac, v\u00e0 \u0111\u00fang th\u1ee9 t\u1ef1, t\u1ea1o n\u1ec1n t\u1ea3ng \u1ed5n \u0111\u1ecbnh cho c\u00e1c t\u1ea7ng \u1ee9ng d\u1ee5ng ph\u00eda tr\u00ean.<\/p>\n\n\n\n

                          2.5. T\u1ea7ng Phi\u00ean (Session Layer)<\/h3>\n\n\n\n

                          T\u1ea7ng Phi\u00ean \u0111\u00f3ng vai tr\u00f2 nh\u01b0 m\u1ed9t ng\u01b0\u1eddi \u201c\u0111i\u1ec1u ph\u1ed1i vi\u00ean\u201d gi\u1eefa hai thi\u1ebft b\u1ecb trong qu\u00e1 tr\u00ecnh giao ti\u1ebfp, \u0111\u1ea3m b\u1ea3o r\u1eb1ng c\u00e1c phi\u00ean k\u1ebft n\u1ed1i (session) \u0111\u01b0\u1ee3c thi\u1ebft l\u1eadp, duy tr\u00ec v\u00e0 k\u1ebft th\u00fac m\u1ed9t c\u00e1ch c\u00f3 tr\u1eadt t\u1ef1. N\u00f3 gi\u00fap hai b\u00ean c\u00f3 th\u1ec3 ti\u1ebfp t\u1ee5c truy\u1ec1n d\u1eef li\u1ec7u t\u1eeb \u0111i\u1ec3m gi\u00e1n \u0111o\u1ea1n n\u1ebfu c\u00f3 s\u1ef1 c\u1ed1, thay v\u00ec ph\u1ea3i kh\u1edfi t\u1ea1o l\u1ea1i to\u00e0n b\u1ed9 ti\u1ebfn tr\u00ecnh.<\/p>\n\n\n\n

                          T\u1ea7ng n\u00e0y c\u00f2n ch\u1ecbu tr\u00e1ch nhi\u1ec7m \u0111\u1ed3ng b\u1ed9 h\u00f3a d\u1eef li\u1ec7u \u2014 v\u00ed d\u1ee5, trong m\u1ed9t t\u1ec7p l\u1edbn \u0111\u01b0\u1ee3c truy\u1ec1n \u0111i, t\u1ea7ng Phi\u00ean c\u00f3 th\u1ec3 ch\u00e8n c\u00e1c \u201c\u0111i\u1ec3m ki\u1ec3m so\u00e1t\u201d (checkpoint) \u0111\u1ec3 n\u1ebfu m\u1ea5t k\u1ebft n\u1ed1i, qu\u00e1 tr\u00ecnh c\u00f3 th\u1ec3 n\u1ed1i l\u1ea1i t\u1eeb v\u1ecb tr\u00ed \u0111\u00f3.<\/p>\n\n\n\n

                          V\u00ed d\u1ee5:<\/strong> M\u1ed9t phi\u00ean \u0111\u0103ng nh\u1eadp SSH ho\u1eb7c m\u1ed9t cu\u1ed9c g\u1ecdi video qua VoIP \u0111\u1ec1u c\u1ea7n c\u01a1 ch\u1ebf qu\u1ea3n l\u00fd phi\u00ean \u0111\u1ec3 \u0111\u1ea3m b\u1ea3o vi\u1ec7c trao \u0111\u1ed5i th\u00f4ng tin \u1ed5n \u0111\u1ecbnh, kh\u00f4ng b\u1ecb gi\u00e1n \u0111o\u1ea1n gi\u1eefa ch\u1eebng.<\/p>\n\n\n\n

                          Ghi ch\u00fa:<\/strong> Trong c\u00e1c h\u1ec7 th\u1ed1ng hi\u1ec7n \u0111\u1ea1i, nhi\u1ec1u giao th\u1ee9c \u0111\u00e3 t\u00edch h\u1ee3p ph\u1ea7n l\u1edbn ch\u1ee9c n\u0103ng c\u1ee7a t\u1ea7ng Phi\u00ean v\u00e0o t\u1ea7ng \u1ee8ng d\u1ee5ng ho\u1eb7c t\u1ea7ng Giao v\u1eadn. Tuy v\u1eady, vi\u1ec7c t\u00e1ch ri\u00eang t\u1ea7ng n\u00e0y trong m\u00f4 h\u00ecnh OSI v\u1eabn mang \u00fd ngh\u0129a l\u00fd thuy\u1ebft quan tr\u1ecdng, gi\u00fap vi\u1ec7c thi\u1ebft k\u1ebf v\u00e0 ph\u00e2n t\u00edch m\u1ea1ng \u0111\u01b0\u1ee3c r\u00f5 r\u00e0ng, c\u00f3 c\u1ea5u tr\u00fac h\u01a1n.<\/p>\n\n\n

                          \n
                          \"T\u1ea7ng<\/figure>\n<\/div>\n\n\n

                          2.6. T\u1ea7ng Tr\u00ecnh b\u00e0y (Presentation Layer)<\/h3>\n\n\n\n

                          T\u1ea7ng Tr\u00ecnh b\u00e0y ho\u1ea1t \u0111\u1ed9ng nh\u01b0 m\u1ed9t \u201cphi\u00ean d\u1ecbch vi\u00ean\u201d gi\u1eefa c\u00e1c h\u1ec7 th\u1ed1ng, \u0111\u1ea3m b\u1ea3o r\u1eb1ng d\u1eef li\u1ec7u t\u1eeb m\u00e1y g\u1eedi c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c hi\u1ec3u \u0111\u00fang \u0111\u1ecbnh d\u1ea1ng \u1edf m\u00e1y nh\u1eadn. N\u00f3 th\u1ef1c hi\u1ec7n c\u00e1c thao t\u00e1c chuy\u1ec3n \u0111\u1ed5i, m\u00e3 h\u00f3a, n\u00e9n v\u00e0 gi\u1ea3i m\u00e3 d\u1eef li\u1ec7u, gi\u00fap c\u00e1c \u1ee9ng d\u1ee5ng c\u00f3 th\u1ec3 trao \u0111\u1ed5i th\u00f4ng tin m\u00e0 kh\u00f4ng g\u1eb7p l\u1ed7i do kh\u00e1c bi\u1ec7t v\u1ec1 chu\u1ea9n bi\u1ec3u di\u1ec5n d\u1eef li\u1ec7u.<\/p>\n\n\n\n

                          C\u1ee5 th\u1ec3, t\u1ea7ng n\u00e0y x\u1eed l\u00fd vi\u1ec7c chuy\u1ec3n \u0111\u1ed5i \u0111\u1ecbnh d\u1ea1ng k\u00fd t\u1ef1 (v\u00ed d\u1ee5: t\u1eeb ASCII sang UTF-8), m\u00e3 h\u00f3a b\u1ea3o m\u1eadt (nh\u01b0 SSL\/TLS trong HTTPS \u0111\u1ec3 b\u1ea3o v\u1ec7 d\u1eef li\u1ec7u kh\u1ecfi nghe l\u00e9n), v\u00e0 n\u00e9n d\u1eef li\u1ec7u \u0111\u1ec3 gi\u1ea3m dung l\u01b0\u1ee3ng truy\u1ec1n t\u1ea3i, gi\u00fap t\u1ed1i \u01b0u t\u1ed1c \u0111\u1ed9 m\u1ea1ng.<\/p>\n\n\n\n

                          V\u00ed d\u1ee5:<\/strong> Khi b\u1ea1n truy c\u1eadp m\u1ed9t website qua HTTPS, t\u1ea7ng Tr\u00ecnh b\u00e0y s\u1ebd m\u00e3 h\u00f3a d\u1eef li\u1ec7u g\u1eedi \u0111i v\u00e0 gi\u1ea3i m\u00e3 d\u1eef li\u1ec7u nh\u1eadn v\u1ec1, \u0111\u1ea3m b\u1ea3o to\u00e0n b\u1ed9 qu\u00e1 tr\u00ecnh di\u1ec5n ra an to\u00e0n v\u00e0 th\u1ed1ng nh\u1ea5t v\u1ec1 \u0111\u1ecbnh d\u1ea1ng gi\u1eefa tr\u00ecnh duy\u1ec7t v\u00e0 m\u00e1y ch\u1ee7.<\/p>\n\n\n\n

                          Nh\u1edd c\u00f3 t\u1ea7ng Tr\u00ecnh b\u00e0y, d\u1eef li\u1ec7u kh\u00f4ng ch\u1ec9 \u0111\u01b0\u1ee3c truy\u1ec1n \u0111i nhanh h\u01a1n m\u00e0 c\u00f2n an to\u00e0n, t\u01b0\u01a1ng th\u00edch v\u00e0 d\u1ec5 d\u00e0ng x\u1eed l\u00fd tr\u00ean c\u00e1c h\u1ec7 th\u1ed1ng kh\u00e1c nhau.<\/p>\n\n\n\n

                          2.7. T\u1ea7ng \u1ee8ng d\u1ee5ng (Application Layer)<\/h3>\n\n\n\n

                          T\u1ea7ng \u1ee8ng d\u1ee5ng l\u00e0 t\u1ea7ng cao nh\u1ea5t trong m\u00f4 h\u00ecnh OSI, n\u01a1i ng\u01b0\u1eddi d\u00f9ng tr\u1ef1c ti\u1ebfp t\u01b0\u01a1ng t\u00e1c v\u1edbi c\u00e1c d\u1ecbch v\u1ee5 m\u1ea1ng. \u0110\u00e2y l\u00e0 c\u1ea7u n\u1ed1i gi\u1eefa ph\u1ea7n m\u1ec1m \u1ee9ng d\u1ee5ng v\u00e0 h\u1ec7 th\u1ed1ng m\u1ea1ng, gi\u00fap c\u00e1c ch\u01b0\u01a1ng tr\u00ecnh nh\u01b0 tr\u00ecnh duy\u1ec7t web, \u1ee9ng d\u1ee5ng email hay ph\u1ea7n m\u1ec1m truy\u1ec1n file c\u00f3 th\u1ec3 giao ti\u1ebfp qua Internet.<\/p>\n\n\n\n

                          T\u1ea7ng n\u00e0y cung c\u1ea5p c\u00e1c giao th\u1ee9c v\u00e0 d\u1ecbch v\u1ee5 h\u1ed7 tr\u1ee3 nhu c\u1ea7u th\u1ef1c t\u1ebf c\u1ee7a ng\u01b0\u1eddi d\u00f9ng, nh\u01b0:<\/p>\n\n\n\n

                            \n
                          • HTTP\/HTTPS:<\/strong> truy c\u1eadp v\u00e0 trao \u0111\u1ed5i th\u00f4ng tin tr\u00ean web.<\/li>\n\n\n\n
                          • FTP:<\/strong> truy\u1ec1n t\u1ec7p gi\u1eefa m\u00e1y t\u00ednh v\u00e0 m\u00e1y ch\u1ee7.<\/li>\n\n\n\n
                          • SMTP v\u00e0 POP3\/IMAP:<\/strong> g\u1eedi v\u00e0 nh\u1eadn email.<\/li>\n\n\n\n
                          • DNS:<\/strong> ph\u00e2n gi\u1ea3i t\u00ean mi\u1ec1n th\u00e0nh \u0111\u1ecba ch\u1ec9 IP \u0111\u1ec3 d\u1ec5 d\u00e0ng truy c\u1eadp website.<\/li>\n<\/ul>\n\n\n\n

                            V\u00ed d\u1ee5, khi b\u1ea1n nh\u1eadp m\u1ed9t \u0111\u1ecba ch\u1ec9 web v\u00e0o tr\u00ecnh duy\u1ec7t, t\u1ea7ng \u1ee8ng d\u1ee5ng s\u1ebd s\u1eed d\u1ee5ng giao th\u1ee9c HTTP ho\u1eb7c HTTPS \u0111\u1ec3 g\u1eedi y\u00eau c\u1ea7u \u0111\u1ebfn m\u00e1y ch\u1ee7 web, sau \u0111\u00f3 nh\u1eadn d\u1eef li\u1ec7u ph\u1ea3n h\u1ed3i v\u00e0 hi\u1ec3n th\u1ecb n\u1ed9i dung trang web cho b\u1ea1n.<\/p>\n\n\n\n

                            Nh\u01b0 v\u1eady, t\u1ea7ng \u1ee8ng d\u1ee5ng kh\u00f4ng ch\u1ec9 gi\u00fap ng\u01b0\u1eddi d\u00f9ng truy c\u1eadp, giao ti\u1ebfp v\u00e0 khai th\u00e1c t\u00e0i nguy\u00ean m\u1ea1ng, m\u00e0 c\u00f2n \u0111\u1ea3m b\u1ea3o m\u1ecdi thao t\u00e1c \u0111\u01b0\u1ee3c th\u1ef1c hi\u1ec7n thu\u1eadn ti\u1ec7n, b\u1ea3o m\u1eadt v\u00e0 hi\u1ec7u qu\u1ea3.<\/p>\n\n\n\n

                            \"T\u1ea7ng<\/figure>\n\n\n\n

                            3. M\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c t\u1ea7ng v\u00e0 c\u00e1ch ch\u00fang t\u01b0\u01a1ng t\u00e1c<\/h2>\n\n\n\n

                            Trong m\u00f4 h\u00ecnh OSI, c\u00e1c t\u1ea7ng ho\u1ea1t \u0111\u1ed9ng ph\u1ed1i h\u1ee3p ch\u1eb7t ch\u1ebd v\u1edbi nhau \u0111\u1ec3 \u0111\u1ea3m b\u1ea3o d\u1eef li\u1ec7u \u0111\u01b0\u1ee3c truy\u1ec1n ch\u00ednh x\u00e1c t\u1eeb thi\u1ebft b\u1ecb g\u1eedi \u0111\u1ebfn thi\u1ebft b\u1ecb nh\u1eadn. M\u1ed7i t\u1ea7ng ch\u1ec9 \u0111\u1ea3m nhi\u1ec7m m\u1ed9t nh\u00f3m ch\u1ee9c n\u0103ng c\u1ee5 th\u1ec3, nh\u01b0ng k\u1ebft h\u1ee3p l\u1ea1i s\u1ebd h\u00ecnh th\u00e0nh quy tr\u00ecnh truy\u1ec1n th\u00f4ng ho\u00e0n ch\u1ec9nh.<\/p>\n\n\n\n

                            Khi d\u1eef li\u1ec7u \u0111\u01b0\u1ee3c g\u1eedi \u0111i, n\u00f3 s\u1ebd \u0111i xu\u1ed1ng t\u1eebng t\u1ea7ng theo c\u01a1 ch\u1ebf encapsulation (\u0111\u00f3ng g\u00f3i):<\/p>\n\n\n\n

                              \n
                            • T\u1ea7ng \u1ee8ng d\u1ee5ng t\u1ea1o ra d\u1eef li\u1ec7u ban \u0111\u1ea7u.<\/li>\n\n\n\n
                            • T\u1ea7ng Tr\u00ecnh b\u00e0y v\u00e0 Phi\u00ean x\u1eed l\u00fd \u0111\u1ecbnh d\u1ea1ng, m\u00e3 h\u00f3a ho\u1eb7c thi\u1ebft l\u1eadp phi\u00ean giao ti\u1ebfp.<\/li>\n\n\n\n
                            • T\u1ea7ng Giao v\u1eadn (Transport) chia d\u1eef li\u1ec7u th\u00e0nh segment, th\u00eam th\u00f4ng tin ki\u1ec3m so\u00e1t truy\u1ec1n t\u1ea3i.<\/li>\n\n\n\n
                            • T\u1ea7ng M\u1ea1ng (Network) g\u1eafn \u0111\u1ecba ch\u1ec9 IP v\u00e0 bi\u1ebfn segment th\u00e0nh packet \u0111\u1ec3 \u0111\u1ecbnh tuy\u1ebfn qua nhi\u1ec1u m\u1ea1ng.<\/li>\n\n\n\n
                            • T\u1ea7ng Li\u00ean k\u1ebft d\u1eef li\u1ec7u (Data Link) ti\u1ebfp t\u1ee5c \u0111\u00f3ng g\u00f3i th\u00e0nh frame v\u1edbi \u0111\u1ecba ch\u1ec9 MAC \u0111\u1ec3 truy\u1ec1n trong m\u1ea1ng c\u1ee5c b\u1ed9.<\/li>\n\n\n\n
                            • Cu\u1ed1i c\u00f9ng, T\u1ea7ng V\u1eadt l\u00fd (Physical) bi\u1ebfn frame th\u00e0nh t\u00edn hi\u1ec7u \u0111i\u1ec7n ho\u1eb7c quang v\u00e0 truy\u1ec1n \u0111i qua d\u00e2y c\u00e1p hay s\u00f3ng v\u00f4 tuy\u1ebfn.<\/li>\n<\/ul>\n\n\n\n

                              Minh h\u1ecda lu\u1ed3ng d\u1eef li\u1ec7u (t\u1eeb tr\u00ean xu\u1ed1ng):
                              [Application Data] \u2192 [TCP Segment] \u2192 [IP Packet] \u2192 [Ethernet Frame] \u2192 [Bits on Wire]<\/strong><\/p>\n\n\n\n

                              Khi \u0111\u1ebfn thi\u1ebft b\u1ecb nh\u1eadn, qu\u00e1 tr\u00ecnh decapsulation (th\u00e1o g\u00f3i) di\u1ec5n ra ng\u01b0\u1ee3c l\u1ea1i: d\u1eef li\u1ec7u \u0111i t\u1eeb t\u1ea7ng V\u1eadt l\u00fd l\u00ean \u0111\u1ebfn t\u1ea7ng \u1ee8ng d\u1ee5ng, m\u1ed7i t\u1ea7ng l\u1ea7n l\u01b0\u1ee3t \u0111\u1ecdc v\u00e0 lo\u1ea1i b\u1ecf header t\u01b0\u01a1ng \u1ee9ng.<\/p>\n\n\n\n

                              Hi\u1ec3u r\u00f5 c\u01a1 ch\u1ebf n\u00e0y gi\u00fap ta x\u00e1c \u0111\u1ecbnh nhanh v\u1ecb tr\u00ed l\u1ed7i trong m\u1ea1ng. V\u00ed d\u1ee5, n\u1ebfu kh\u00f4ng ping \u0111\u01b0\u1ee3c, v\u1ea5n \u0111\u1ec1 c\u00f3 th\u1ec3 n\u1eb1m \u1edf t\u1ea7ng M\u1ea1ng (IP, \u0111\u1ecbnh tuy\u1ebfn) ho\u1eb7c t\u1ea7ng V\u1eadt l\u00fd (c\u00e1p, t\u00edn hi\u1ec7u). \u0110\u00e2y c\u0169ng l\u00e0 n\u1ec1n t\u1ea3ng quan tr\u1ecdng \u0111\u1ec3 ph\u00e2n t\u00edch, thi\u1ebft k\u1ebf v\u00e0 kh\u1eafc ph\u1ee5c s\u1ef1 c\u1ed1 m\u1ea1ng chuy\u00ean nghi\u1ec7p.<\/p>\n\n\n\n

                              \"M\u1ed1i<\/figure>\n\n\n\n

                              4. Vai tr\u00f2 c\u1ee7a m\u00f4 h\u00ecnh OSI trong h\u1ecdc t\u1eadp v\u00e0 th\u1ef1c t\u1ebf<\/h2>\n\n\n\n

                              M\u00f4 h\u00ecnh OSI kh\u00f4ng ch\u1ec9 l\u00e0 ki\u1ebfn th\u1ee9c l\u00fd thuy\u1ebft m\u00e0 c\u00f2n mang gi\u00e1 tr\u1ecb th\u1ef1c ti\u1ec5n l\u1edbn trong ng\u00e0nh m\u1ea1ng v\u00e0 c\u00f4ng ngh\u1ec7 th\u00f4ng tin.<\/p>\n\n\n\n

                                \n
                              • Trong h\u1ecdc t\u1eadp:<\/strong> OSI gi\u00fap ng\u01b0\u1eddi h\u1ecdc hi\u1ec3u c\u1ea5u tr\u00fac ho\u1ea1t \u0111\u1ed9ng c\u1ee7a m\u1ea1ng theo t\u1eebng t\u1ea7ng, t\u1eeb v\u1eadt l\u00fd \u0111\u1ebfn \u1ee9ng d\u1ee5ng. Vi\u1ec7c t\u00e1ch bi\u1ec7t ch\u1ee9c n\u0103ng gi\u00fap d\u1ec5 ti\u1ebfp thu, n\u1eafm b\u1eaft logic truy\u1ec1n d\u1eef li\u1ec7u v\u00e0 c\u00e1ch c\u00e1c giao th\u1ee9c ph\u1ed1i h\u1ee3p.<\/li>\n\n\n\n
                              • Trong th\u1ef1c t\u1ebf qu\u1ea3n tr\u1ecb m\u1ea1ng:<\/strong> K\u1ef9 s\u01b0 s\u1eed d\u1ee5ng m\u00f4 h\u00ecnh OSI nh\u01b0 m\u1ed9t \u201cb\u1ea3n \u0111\u1ed3 t\u01b0 duy\u201d khi x\u1eed l\u00fd s\u1ef1 c\u1ed1. Ch\u1eb3ng h\u1ea1n, n\u1ebfu m\u1ea5t k\u1ebft n\u1ed1i v\u1eadt l\u00fd \u2192 ki\u1ec3m tra t\u1ea7ng 1; n\u1ebfu kh\u00f4ng ping \u0111\u01b0\u1ee3c \u2192 ki\u1ec3m tra t\u1ea7ng 3; n\u1ebfu website kh\u00f4ng ph\u1ea3n h\u1ed3i \u2192 xem t\u1ea7ng 7. Nh\u1edd v\u1eady, vi\u1ec7c x\u00e1c \u0111\u1ecbnh nguy\u00ean nh\u00e2n v\u00e0 kh\u1eafc ph\u1ee5c l\u1ed7i tr\u1edf n\u00ean c\u00f3 h\u1ec7 th\u1ed1ng h\u01a1n.<\/li>\n\n\n\n
                              • Trong thi\u1ebft k\u1ebf v\u00e0 ph\u00e1t tri\u1ec3n:<\/strong> OSI l\u00e0 chu\u1ea9n chung gi\u00fap c\u00e1c nh\u00e0 s\u1ea3n xu\u1ea5t thi\u1ebft b\u1ecb, ph\u1ea7n m\u1ec1m ho\u1eb7c giao th\u1ee9c \u0111\u1ea3m b\u1ea3o kh\u1ea3 n\u0103ng t\u01b0\u01a1ng th\u00edch v\u00e0 m\u1edf r\u1ed9ng.<\/li>\n\n\n\n
                              • Trong b\u1ea3o m\u1eadt:<\/strong> M\u1ed7i t\u1ea7ng c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c \u00e1p d\u1ee5ng c\u01a1 ch\u1ebf b\u1ea3o v\u1ec7 ri\u00eang \u2014 m\u00e3 h\u00f3a d\u1eef li\u1ec7u \u1edf t\u1ea7ng tr\u00ecnh b\u00e0y, x\u00e1c th\u1ef1c \u1edf t\u1ea7ng phi\u00ean, hay firewall \u1edf t\u1ea7ng m\u1ea1ng. \u0110i\u1ec1u n\u00e0y gi\u00fap x\u00e2y d\u1ef1ng h\u1ec7 th\u1ed1ng b\u1ea3o m\u1eadt \u0111a l\u1edbp.<\/li>\n<\/ul>\n\n\n\n

                                T\u00f3m l\u1ea1i, m\u00f4 h\u00ecnh OSI \u0111\u00f3ng vai tr\u00f2 nh\u01b0 x\u01b0\u01a1ng s\u1ed1ng v\u1ec1 m\u1eb7t t\u01b0 duy v\u00e0 t\u1ed5 ch\u1ee9c trong c\u1ea3 vi\u1ec7c h\u1ecdc, thi\u1ebft k\u1ebf, v\u00e0 v\u1eadn h\u00e0nh h\u1ec7 th\u1ed1ng m\u1ea1ng hi\u1ec7n \u0111\u1ea1i.<\/p>\n\n\n\n

                                5. K\u1ebft lu\u1eadn<\/h2>\n\n\n\n

                                M\u00f4 h\u00ecnh OSI l\u00e0 n\u1ec1n t\u1ea3ng t\u01b0 duy quan tr\u1ecdng trong l\u0129nh v\u1ef1c m\u1ea1ng m\u00e1y t\u00ednh. Th\u00f4ng qua vi\u1ec7c chia nh\u1ecf h\u1ec7 th\u1ed1ng truy\u1ec1n th\u00f4ng th\u00e0nh 7 t\u1ea7ng \u0111\u1ed9c l\u1eadp, n\u00f3 gi\u00fap con ng\u01b0\u1eddi hi\u1ec3u r\u00f5 h\u01a1n v\u1ec1 c\u00e1ch d\u1eef li\u1ec7u di chuy\u1ec3n, c\u00e1ch c\u00e1c giao th\u1ee9c ph\u1ed1i h\u1ee3p, v\u00e0 c\u00e1ch x\u1eed l\u00fd s\u1ef1 c\u1ed1 theo t\u1eebng l\u1edbp ch\u1ee9c n\u0103ng. C\u1ea5u tr\u00fac ph\u00e2n t\u1ea7ng n\u00e0y th\u1ec3 hi\u1ec7n t\u01b0 duy thi\u1ebft k\u1ebf h\u01b0\u1edbng m\u00f4-\u0111un \u2013 n\u01a1i m\u1ed7i t\u1ea7ng \u0111\u1ea3m nhi\u1ec7m m\u1ed9t vai tr\u00f2 c\u1ee5 th\u1ec3 nh\u01b0ng v\u1eabn li\u00ean k\u1ebft ch\u1eb7t ch\u1ebd v\u1edbi c\u00e1c t\u1ea7ng kh\u00e1c \u0111\u1ec3 h\u00ecnh th\u00e0nh m\u1ed9t h\u1ec7 th\u1ed1ng ho\u00e0n ch\u1ec9nh.<\/p>\n\n\n\n

                                Gi\u00e1 tr\u1ecb l\u1edbn nh\u1ea5t c\u1ee7a m\u00f4 h\u00ecnh OSI kh\u00f4ng n\u1eb1m \u1edf vi\u1ec7c n\u00f3 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng tr\u1ef1c ti\u1ebfp trong th\u1ef1c t\u1ebf, m\u00e0 \u1edf ch\u1ed7 n\u00f3 \u0111\u1ecbnh h\u00ecnh c\u00e1ch ch\u00fang ta t\u01b0 duy v\u00e0 ph\u00e2n t\u00edch m\u1ea1ng. Nh\u1edd c\u00f3 m\u00f4 h\u00ecnh n\u00e0y, vi\u1ec7c h\u1ecdc, gi\u1ea3ng d\u1ea1y, ph\u00e1t tri\u1ec3n giao th\u1ee9c v\u00e0 b\u1ea3o m\u1eadt m\u1ea1ng \u0111\u1ec1u tr\u1edf n\u00ean c\u00f3 h\u1ec7 th\u1ed1ng v\u00e0 logic h\u01a1n.<\/p>\n\n\n\n

                                M\u1eb7c d\u00f9 Internet hi\u1ec7n nay v\u1eadn h\u00e0nh ch\u1ee7 y\u1ebfu d\u1ef1a tr\u00ean m\u00f4 h\u00ecnh TCP\/IP, nh\u01b0ng b\u1ea3n ch\u1ea5t c\u1ee7a TCP\/IP v\u1eabn ph\u1ea3n \u00e1nh nhi\u1ec1u nguy\u00ean l\u00fd c\u1ee7a OSI. \u1ede g\u00f3c nh\u00ecn \u0111\u00f3, OSI \u0111\u00f3ng vai tr\u00f2 nh\u01b0 \u201cng\u01b0\u1eddi th\u1ea7y n\u1ec1n t\u1ea3ng\u201d, c\u00f2n TCP\/IP l\u00e0 \u201c\u1ee9ng d\u1ee5ng th\u1ef1c ti\u1ec5n\u201d c\u1ee7a nh\u1eefng kh\u00e1i ni\u1ec7m \u0111\u00e3 \u0111\u01b0\u1ee3c \u0111\u01a1n gi\u1ea3n h\u00f3a v\u00e0 t\u1ed1i \u01b0u h\u01a1n.<\/p>\n\n\n\n

                                6. T\u00e0i li\u1ec7u tham kh\u1ea3o<\/h2>\n\n\n\n

                                [1] A. S. Tanenbaum and D. J. Wetherall, Computer Networks<\/em>, 6th ed. Pearson, 2011.
                                [2] J. F. Kurose and K. W. Ross, Computer Networking: A Top-Down Approach<\/em>, 8th ed. Pearson, 2021.
                                [3] International Organization for Standardization, ISO\/IEC 7498-1:1994 \u2013 Information technology \u2014 Open Systems Interconnection \u2014 Basic Reference Model: The Basic Model<\/em>, ISO, 1994.
                                [4] G. M. Garner, Networking Essentials<\/em>, 7th ed. Cengage Learning, 2020.
                                [5] IEEE Computer Society, IEEE Std 802.3-2018 \u2014 IEEE Standard for Ethernet<\/em>, IEEE, 2018.<\/p>\n","protected":false},"excerpt":{"rendered":"

                                M\u00f4 h\u00ecnh OSI l\u00e0 n\u1ec1n t\u1ea3ng t\u01b0 duy quan tr\u1ecdng trong l\u0129nh v\u1ef1c m\u1ea1ng m\u00e1y t\u00ednh. Th\u00f4ng qua vi\u1ec7c chia nh\u1ecf h\u1ec7 th\u1ed1ng truy\u1ec1n th\u00f4ng th\u00e0nh 7 t\u1ea7ng \u0111\u1ed9c l\u1eadp, n\u00f3 gi\u00fap con ng\u01b0\u1eddi hi\u1ec3u r\u00f5 h\u01a1n v\u1ec1 c\u00e1ch d\u1eef li\u1ec7u di chuy\u1ec3n, c\u00e1ch c\u00e1c giao th\u1ee9c ph\u1ed1i h\u1ee3p, v\u00e0 c\u00e1ch x\u1eed l\u00fd s\u1ef1 c\u1ed1 theo t\u1eebng l\u1edbp ch\u1ee9c n\u0103ng<\/p>\n","protected":false},"author":1,"featured_media":2023,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"googlesitekit_rrm_CAowieHDDA:productID":"","footnotes":""},"categories":[19],"tags":[],"class_list":["post-2022","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-mang-may-tinh"],"_links":{"self":[{"href":"https:\/\/kienthucmo.com\/vi\/wp-json\/wp\/v2\/posts\/2022","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kienthucmo.com\/vi\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kienthucmo.com\/vi\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kienthucmo.com\/vi\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/kienthucmo.com\/vi\/wp-json\/wp\/v2\/comments?post=2022"}],"version-history":[{"count":2,"href":"https:\/\/kienthucmo.com\/vi\/wp-json\/wp\/v2\/posts\/2022\/revisions"}],"predecessor-version":[{"id":3225,"href":"https:\/\/kienthucmo.com\/vi\/wp-json\/wp\/v2\/posts\/2022\/revisions\/3225"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/kienthucmo.com\/vi\/wp-json\/wp\/v2\/media\/2023"}],"wp:attachment":[{"href":"https:\/\/kienthucmo.com\/vi\/wp-json\/wp\/v2\/media?parent=2022"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kienthucmo.com\/vi\/wp-json\/wp\/v2\/categories?post=2022"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kienthucmo.com\/vi\/wp-json\/wp\/v2\/tags?post=2022"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}