Ʈ(2)

    ̼/ geba@linuxlab.co.kr
    GEVA@hitel.net
    ý Ʈũ

     

 

6. Ʈ

     

    6.1   ī

    ī PC Ʈ ִ ġ̰, NIC(NETWORK INTERFACE CARD) Ѵ.

    δ Ethernet 10M, 100M, ATM, 16M TOKEN ī ִ. μ 10M Ethernet ī尡 ̷ 100M Ethernet Ƽ鼭 ̴ ߼̴. δ 3COM, INTEL, SMC ȸ ܿ 븸 ɺ ִ.

    NIC ī ÿ ־ Name Value ִ ȸ縦 ϴ ͵ 븸굵 ׿ ʰ ȣȯ پ. ߿ ۾ ϴ 3COM, INTEL ž߰ Ӹ ׸ ʿ䰡 . 븸 꿡 ȣȯ ȵ ָ Դ 찡 ̹ ǰ̶ ū . ׸ PCI ī ִ. ĸ Ѵٸ PCI ī尡 ӵ ̴.

    ī ij̺ ٸ. ̴ RJ-45 ϴ TP ܿ 10BASE-2 ϴ BNC 10BASE-5 ϴ AUIƮ ִ. ī带 ޺̶ Ѵ. ׷ UTP ̺ ϰ ֱ RJ-45 ϴ TP ϴ ̴. ׷ 10BASE-2(THIN ̺) ̿ Ʈ ̶ BNC ޷ִ ī带 Ѵ.

     - ̹

    ̹ ̴ Ǵ ū Ʈ ͸ ޴ Ʈ ̽ ͸ ϴ Ʈ̴. ̹ ϵ ʱȭϰ Ʈ Ͽ MAC LAYER ͸ ۸Ͽ LAYER Ѱִ Ѵ.
    OSI MODEL ־ ̹ LAYER 2 DATA LINK LAYER ۵Ͽ Ʈ ̽ ʹ LAYER 1 PHYSICAL LAYER ۵Ѵ.

    - ̹

    1) ̹(MONOLITHIC DRIVER)
    ̹ MAC ̹ ݰ ӵ SPEC ȸ ̽ Ģ ۼȴ. ̰͵ ϳ Ư STACK Ǵ PROGRAM Ѵ. δ RAM ̿ Ե 뼺 . NIU.E ̹ ϸ PROGRAM(DRIVER AND PROTOCOL) Ϻΰ CARD MEMORY DOWNLOADING Ǿ SYSTEM MEMORY شȭ UB ؾ߸ ϴ.

    2) ǥ ̹
    ̹ STACK ̽ ͸ ϱ Ͽ Ưμ Ʒ ִ.

      -NDIS(Network Interface Driver Specification)

      MICROSOFT 3COM ߵ μ LAN MANAGER ̽ ǥ Ѵ.

         MANGER : PROTOCOL.INI FILE κ MAC ̹
                                       ̵ ʱȭϴµ Ѵ.
        MAC ̹ : MEDIA ACCESS CONTROL DRIVER μ ".DOS", ".OS2"
                               Ȯ
         STACK : NDIS SPEC STACK

      -ODI(Open Datalink Inerface) ̹

      NOVELL ̽

        MAC ̹ : ODI, SPEC MAC DIRVER NET. CFG FILE о
                               ʱȭȴ.
        LSL : STACK MILD ROUTING Ѵ.
        STACK1,2 : IPXODI ODI SPEC TCP/IP

      - PDS(Packet Driver Specification) DRIVER

      FTP Ʈ Ͽ ߵ ̹ .

     

    6.2  

    ʹ ȣ ø ȴ. ͸ Ÿ Ϸ ȣ ٽ ȣ ؼ Ÿ . ϴ ̴ϴ. 꿡 Ǿ ְų 麻 ׷ ҰŸ餤 ̺ ״ϱ.

    ̺ ͸ ִ Ÿ ѵǾ ִ. ̺ ġ ̺ ̴ 185̰ β ̺ 쿡 500̴. ̷ ѵ Ÿ ⿡ ȣ Ͽ ͸ μ Ʈũ ̸ Ȯ ϰ Ѵ. OSI(Open System Interconnection) 7 ߾  ȣ OSI 1 , (Physical Layer) ̷.

     

    6.3  긮

    긮 ٸ ϴ ٸ ֵ ٸ Ʈ ̿ ͸ ų Ѵٰ ȴ. ̷μ ȿ Ը Ʈ ȣ 浹 Ͼ Ȯ , ̷ 浹  ʿ ߻ ȣ ٸ Ѿ ϰ Ѿ ؼ Ѱִ ְ ȴ.

    긮 ɰ Ƽ-ũ Ͽ Ȥ LAN ϳ LAN ְ Ÿ ִ LAN 뼱 WAN(Wide Area Network) ũ Ͽ ϳ Ѵ. WAN ũ Ÿ ־ սǷ ĿǷ ι(Line Backup) ϴ ũ ϴ . ʹ ȣ ɰ IP ּ ϰ Ʈũ Ʈκ پ ݵ Ͽ Ʈũ Ŷ ϴ Ƽ-ũ, Ƽ- Ѵ.

    ֱ 긮 ܵ ̴ Ϳ Ͷ Ҹ⵵ ϰ, 꿡 SWITCHING HUB Ҹ⵵ Ѵ.

     

    6.4  HUB

    带 ϱ ġ̴.  ܼƮ Ƽ ܼƮ͵ ϰ پ. ֱ , 긮, ϳ ÷ ִ. ʿ ɸ ٷ · ϱ⵵ Ѵ. δ (Dummy) , ڸƮ , Ŀ ְ, ſ ϰ SOHO . ڸƮ Ʈ  ϰ Ÿ ִ. δ. ׸ Ŀ Ը ũ׷̳  ϴ. ׾Ƽ ڸ ʰ ŷ ̺ ϸ ӵ ϵ ְ ϱ⵵ . 긦  ϰų ̺ ִ Ȯϰ, ׷ ̺ ũν ̺  Ʈ ϰ Ǵϱ ̴. SOHO HUB ƿ ƮƮ ̺ε ϵ X-PORT ϱ⵵ Ѵ.

     

    6.5  SWITCHING HUB

    SWITCH HUB PORT 긮 ִ Ͱ . Ʈ ڽ ȣ Ȯ ˱ HUB PORT ӵǴ ʷ ӵ ϵ ʰ 뿪 ִ ̴. ġ ϸ ߴ LAN ī, , ̺ ״ ִ. ġ ȴ ص Ϲ 꿡 δ. ȿ ŷ ִ ̴. ׷ Ʈ SERVER 븸 尡 SERVER ϰ Ǿ Ʈ л ʱ ̷ ū ȿ ƴ. ̰ 尡 ȿ ִ. ġ ־ ϴ Ѵٸ 뿪 2 þ ȴ.

    ġ Ī Ŀ ũ ִ.

      CUT THROUGH
      - ּ κи  Ͽ ּҸ ˻ϱ
         ӵ .
      - üũ ƴ.
      - ӵ ٸ MEDIA(FDDI, ATM, 10BASE-T) ִ.
      - ԸȮ忡 . Ʈ ϰ ۿ ؾ ϴ
         찡 (Ʈ ȭ )

      STORE & FORWARD
      - , , ۽ ּҸ ˻Ѵ.
      - üũ
      - Ʈ ͸
      - VIRTUAL LAN
      - CUT-THROUGH Ŀ ӵ

    ϳ ϱ⵵ ϰ ȥϿ ϱ⵵ Ѵ.

    ġ Űĺε ũ ϳ Ȯ强 ִ Ʈ ġ ϵ ġ ϵ ġ , ġ ŴƮ Ȱ ִ Ʈ ġ .

    ڸ о ð ϴ 3 ġ ִ ̳ δ ΰ Ȳ̴.

    ġ ¿ϴµ ִ. CPU ɰ ũ, MAC ADDRESS ũ Ȳ ֱ Ʈ ݿ ´ ġ Ͽ Ѵ. ߿ Ʈ  л ִİ ̴. ߳ ʷ ִ. ġ غ Ʈ ý Ȯ强, ̼, ɰ , ġ ̼, 麻 , FAULT TOLERANCE

    VLAN ῡ ֹ ʰ ϴ ִ. Aڴ A Ǵ ̴. ڸ Űܼ ٸ A 鸸 ִ ְ ִ.

      VIRTUAL LAN ʿ伺
      - Ÿ μ Ʈ WORKGROUP
      - WORKGROUP ü
      - μ 濡 NETWORK SEGMENT
      - ʿ ⺻ Ʈ и

     

    6.6  

    ʹ Ѹ θ ãְ ִ . 츮 ͳ ִ Ͱ ϱ ̴. ʹ WAN Ʈ LAN Ʈ Ǿ ְ Ʈ ٸ , RFC877(Requests For Comments) X.25 Ȥ (Frame Relay), PPP(Point-TO-Point) Ͽ ͸ ȯѴ. Ϲ ͸ ȯϴ WAN ȸ縶 Ȥ ٸ. 뼱 ٸ ȸ ͵ ̿ PPP ̿ϰ ٸ WAN ɼ δ Ϳ ϴ ǥȭ ޶ ִ. , ȸ Ͱ RFC877 Ѵٸ ٸ ȸ ǰ X.25 Ͽ ִ. 긮 ͸ OSI 7 ߾ 긮 2 ũ(Data Link Layer) Ͱ óǰ ʹ 3 Ʈũ(Network Layer) Ͱ óȴ. Ϲ κ ǸŵǴ ͳ״ 긮 ԵǾ ־ (BRouter : Bridge/Router) Ҹ.

    ֱ ʹ ׸Ʈ Ʈ ִ 2/3 ġ ڸ ְ ܰ WAN ִ ߼̴. ͸ Ѵٸ Ƽ ִ ǰ Ѵ. ͳݸ Ѵٸ IP õǴ ǰ 絵 糪 ٸ Ʈ IPX/SPX NETBIOS Ѵٸ Ƽ ϴ ǰ ʿ伺 ̴. Ƽ ȵȴٸ 긮 ־ ڽ ó ٸ Ʈ ѱ ̴. κ Ϳ ʴ NETBEUI Ʈ ϰڴٸ 긮 ɸ ϴ.

     

    6.7  DSU/CSU

    DSU CSU 츮 ̶ Ͻø ˴ϴ. ȣ Ƴαװ ƴ϶ и ޴ Ÿ Դϴ.

    64/128K DSU ϰ ̻ ӵ 512K/T1(1.544Mbps)̻󿡼 CSU ϽŴٰ Ͻø ˴ϴ.

     

    6.8  Ʈ

    Ʈ̴ ٸ ϴ Ʈ ߰ 뿪 شٰ ø ˴ϴ. IPX/SPX ϰ TCP/IP Ѵٸ  Ʋ ǻ ȴ. ̷ ߰ G/W ġָ ϴϴ.

    G/W پմϴ. IBM ȣƮ TCP/IP SNA G/W, NOVELL NETWARE TCP/IP IPX G/W ִ.

     

    6.9  

    Ŭ̾Ʈκ 䱸 ۾ Ͽ ٽ Ŭ̾Ʈ ִ Ѵ. ͸ , ִ ͼ , ִ. , ̳ ߸ Ʈ , , α׷ Ʈ, , ѽ, , Ÿ ϵ ڿ ֵ Ѵ. ұԸ Ʈ 1 񽺸 ϸ Ը Ʈ ϳ 񽺿 Ѵ. ׸ 񽺵 þƼ ϰ ȴ. , , ѽ, , , FTP, NEWS

     

    6.10  NOS

    NOS Ʈ ü ϰ ϴ γ Ѵ. NOS ϴ  ϴ ȴ. ֱٿ Ը ƴ Ը ƴϴ Ʈ ȿ NOS ϱ⵵ Ѵ.

    NOS .

      6.10.1  NT

      ʰ NOS Ǿ NOS̴. پ ܰ踦 ġ鼭 ̷.

      6.10.2  NETWARE

      NT ټ κ Ǿ Դ. ȼ پ Ը Ʈ ִ NDS ִ. ݿ 5.0 MOAB ִ.

      6.10.3  UNIX

      ȭ(?) ģ NOSμ ͳ ü ص ƴ ̴. Ϻ Ƽ׽ŷ Ƽ ϸ ͳݰ Ʈ ࿡ ڸ ִ NOS ̴.

      6.10.4  LINUX

      ڶ ȵ帮ڽϴ. ֱ ް ִ NOS ְڽϴ. Ϻ Ƽ׽ŷ Ƽ ϸ鼭 ޸Ʈ ִ NOS ̴. ΰ б  Ǵ NOS ̴.

     

    6.11 ̺

     Ʈũ ġ ̺ Ǿ ġ ٸ ġ ͸ ϰ Ѵ. Ʈũ ÿ ִ ̺ Ϲ ũ ƮƼ ̺(Twisted-Pair Cable), ̺(Coaxial Cable), ̺(Fiber Optical Cable) зѴ. Ϲ ̺ ִ Ʈũ Ը ȣ Ͽ ϴ (Repeater) Ȥ ϸ Ÿ Ʈũ ϰ ϴ (Hub), ִ Ʈũ Ʈũ ִ 긮(Bridge) Ͽ Ÿ ִ. ׷ ü Ʈũ Ʈũ 忡 Ѱ谡 ִ.

      6.11.1  ƮƼ ̺(Twisted Pair Cable)

      ƮƼ ̺ Ʈũ ϴ ̺ ġ ִ ̴̺. ̺ ϳ Ǿ ־ ܺο ߻Ǵ κ ϰ RF(Radio Frequencies) 縦 δ. ׷ ܺηκ ϰ Ѵ. ƮƼ ̺ ġ UTP(Unshield Twisted Pair) ̺ UTP ġ UTP Ÿ ϴ STP(Shield Twisted Pair) ִ. ̵ Ϲ 긦 ̿Ͽ Ʈũ ȴ. UTP 꿡 ܸ ̼DZ ͸ ִ ִ Ÿ 100̰ STP 300̴.

      6.11.2   ̺(Coaxial Cable)

      Ʈũ ÿ Ǵ ̺ ܺο ߻ϴ ķκ ϰ 뿪 ϹǷ ׸Ʈ Ʈũ ϴ(Backbone) ִ. ̺ ̺(Thin Coaxial Cable) β ̺(Thick Coaxial Cable) ִ.

      β ̺ ׸Ʈ ġ ִ ̺ ̰ 500 ̰ ϳ ׸Ʈ 100 带 ִ.

      ̺ ׸Ʈ ġ ִ ̰ 185 ̰ ϳ ׸Ʈ 30 带 ִ.

      6.11.3   ̺(Optical Fiber Cable)

      100Mbps ۷ ϴ ̺ öƽ ̺(Plastic-fiber Cable) ̺(Glass-fiber Cable) ִ. öƽ ̺ Ÿ ̺ ʰ Ұ ȵǴ ̴̺. Ϲ ̺ Ѵ. ̺ ̺ Ȥ ƮƼ ̺ ӵ Ÿ Ѵ. ̹Ƿ ܺηκ ʴ´. ̷ ̺ 1ųι(Km) ġǾ ӵ 100Mbps ̰ 500 쿡 200Mbps ӵ Ѵ. ͸ ϴ õ ̿ LED(Light-emitting Diode) ִ. ̿ LED ۷ Ѵ.

     

7.

    е Ƹ ø鼭 ӵ 10Mۿ ȵǴ ñϽ ̴ϴ. Gigabit(109) ȭ ܰ迡 ֽϴ. ׷ 麻̳ ῡ ̰ ְ ߿ ׸ . ٷ ܰ Ʒ̸鼭 10M 100M ȭ Ǿְ ̷ ִ. 10M ߾.

      7.5.1  FDDI

      1990 ANSI X3T9.5 ǥ Ǿ (Ʈ ִ 200Km 1000CONNECTION ) Ʈ ̸ ϴ FDDI Ʈ 麻 忡 Ȯ ġ ϰ ִ. ŷڼ ذ θ äǰ ֽϴ. ׷ FDDI ռ ϰ ִ ſ NIC ϰ Դϴ. ũž ӿ ̷ Ѵٴ ϱ FDDI īװ 5 UTP ۵Ų 쿡 ٸ ̱ Ƶ ũž ӿ ˸ ʰ 麻 ־ ݷƮ 麻 ߼̴.

     

    7.3  ATM

    Ʈŷ ̷ þ ATM LAN WAN , 53BYTE CELL Ƽ÷̰ Ī ϴ ϰ, پ MEDIA TYPE پ ӵ ۵ϴ INTERFACE , , Ŀؼ Ѵ. ׷ ũ ž μ ȴ. ATM Ŀؼ Ư Ʈ ȯ濡 ū ȭ 䱸Ѵ.

    ATM Ʈ Ŀؼ ATM ݰ LAN ϰ ִ ĿؼǸ 񽺿 ߰踦 LANE(LAN EMULATION) ־ Ѵ. LANE ϸ ߻Ű, ϸ, Ų. NOS ڿ Ŀؼ ϱ ATM 츱 ִ ø̼ ϱ ũ鿡 Ȱ ̴. ұϰ ķ۽ Ը Ʈ FDDI ATM 麻̳ Ʈ Ǿ ִ.

     

    7.4  100VG-ANYLAN

    HP 100M LAN ݷμ ANYLN ӳƮ ̷̱ϴµ ־ ذش. ANYLAN ̴ݰ ū Ÿ ENCAPSULATION Ͽ ϹǷ ڿ ؼ ʿġ ʴ. ANYLAN ϰ ̺ ι Ȱ ִ. ׷ δ ANYLAN ׼ ٸ 䱸 켱(DEMAND PRIORITY) ν Ʈ ڳ ڴ ο ޾ƾ Ѵٴ ̴. 100BASE-T 浹 ROUND ROBIN MAC ϱ ڳ ڿ ̳ ־ ο ֱ ũ ȰDZ δ.

     

    7.5  100BASE-T

    100BASE-T ϸ鼭 ڿ ״ ִٴ ̷ ִ. 100BASE-T ο NIC 긦 ʿ Ѵٴ ٸ ݱ , , ״ 츱 ִٴ ٸ ϴ. ׷ 100BASE-T Կ ߻ϴ ū ̴. ׸Ʈ 210m ̻ Ȯ ϰ ׸Ʈ ִ 2 ȩ(HOP)ۿ 㰡 ʴ´. ׷ Ŀ 긦 ̿ ׸Ʈ Ʈ ÷ ϰ ִ.

     

    7.6  Ӹ MIGRATION

    Ʈ

    1 ܰ : SHARD HUB -> 10/100Mbps SWITCH ġ

    - 10/100Base -T Switch
    - 100Base -T ׷̵
    - ׸Ʈ Ʈ ġ

    2 ܰ : POWER ڿ 100Mbps Ҵ

    - 100Base -T Hub
    - ũ ž 100Mbps
    - 100Mbps ߰ л

    3 ܰ : WORKGROUP 100Mbps ü

    - 100Base -T ̽
    - 100Base -T ߰
    - ο ũž 100Mbps ߰
    - ATM

    ̱׷̼ ܰ躰 ҿ
    1 ܰ 10/100 PCI, EISA NIC, 10/100BASE-TX SWITCH
    2 ܰ ڸƮ PCI NIC, 10/100BASE-FX SWITCH, 100BASE-TX HUB
    3 ܰ 10/100 PCI, EISA NIC, 100BASE-TX HUB, 100Mbps ROUTER INTERFACE, 10/100
    MODULAR BACKBONE SWITCH, 100M MODULAR WORKGROUP SWITCH

     

8. ߼ұԸ Ʈ

    8.1  ұԸ Ʈ

    ұԸ Ʈ 5~20 Ŭ̾Ʈ ȯε 1 ó ִ.

    8.2  ߱Ը

    50~100 Ǵ Ŭ̾Ʈ Ը𿡼 ġ Ǿִ.

     

9.

    Ʈ ̾߱ϵ ģ ȴ. ͺ䳪 ڽ 踸 Ʈ ݵ ׿ (?) ƿ ̴. 鼭 ߿ ϳ ͵ Ű ̴. ȸ糪 Ʈ Ѵٸ ׻ Ŵ ϰ θ ϱ ٶ. Ʈ ѹ ƴ϶ ȭ ϴ Ӿ ɰ ʿ Ѵ.

    ̷ ͵鸸 ٸ ư ֹ ƴ϶  ִ Ȱ ̴.


               

Ʈ(TRAFFIC)
    Ư ۷ ð 帣

MAC(MEDIA ACCESS CONTROL)
     ۷θ ϴ LAN ܸⰡ ۷θ ȿ ְ
    ̿ϱ . ǥ δ ̴ݿ ϴ CSMA/CD
     ִ.

MAC ADDRESS
    Ʈ 񸶴 ּҸ ִ. ּҴ 迡
     Ʈ 񸶴 ȣ οǸ ּ
    . ּҸ MAC 巹 Ѵ. Ʈ IP 巹
    ϸ ذ ߻Ͽ ó ƴ. LAN NMS
     ϴµ ̶ IP 巹 ־ ִ. IEEE802 ȸ
     巹 ǥȭ 48 Ʈ Ǵ 16 Ʈ 巹
    ϵ ϰ ִ.


     ǻͰ  ϸ ϴ (޽) ȯ
    ޽ (FORMAT) ⺻Ģ .

NOS(NETWORK OPERATING SYSTEM)
    ǻͰ Ʈ Ǿ ǻ͵ ϰ ɷ
     θ ̿ ֵ ִ ݰ Ʈ .
    NO ȣƮ ü Ʈ ϸ Ʈ
    ȣƮ ǰ ִ α׷ ؼ ȴ.
    ϱⰡ ϰ Ʈ Ȱ ִٴ
     ڸ ٸ Ƿ
    ϴٴ ִ.

TCP/IP
    ͳݿ ϴ ݷμ ǻ Ʈ 󿡼 ̿ϴ
     ǻ ǥ 1983 ǿȭǾ.

(Mainframe)
    뷮 ũ óӵ ڰ ÿ ̿
    ִ Ը ǻ.  â ǻͰ õ
     ġ ö ȿ · ̷
    ̴.

RIGHTSIZING
     ִ Ʈ Ͽ ڿ ȿ ϴ .

NIC(Network Interface Card)
    PC ̼ Ʈ ֵ Ȯ Կ Űų Ǿ
    ִ ī.

̴
    1976 Ͻ ҿ ߵ LAN ̸. ̴ ǻͿ
    ̴ ǻ͸ ϱ ߵ, IEEE802.3 ǵ ǥؿ
     о߷ Ȯ ƴ. ̴ݿ
    ϸ鼭 Ʈ CSMA/CD .
    ִ 10Mbps ӵ ̴̺ 2.5Km Ǹ,
     ̴ ִ 300m.

CSMA/CD(CARRIER SENSE MULTIPLE ACCESS WITH COLLISION
    DETECTION)
    ݼ \/浹. ̴ ϴ ۷
    (MAC) ̴. ͸ ۽ϰ ϴ ġ
    ۷θ ؼ ȣ ȣ ǰ
    Ȯ ͸ Ѵ. 浹 Ǹ ð
    ȴٰ ٽ Ѵ.

׸Ʈ
    ̴ ̿ ڰ μ  ġϴ Ʈ .
    LAN ܸκ 浹 ˸ ȣ ޵Ǵ ,
    긮 ͵ LAN ġ ׸Ʈ
     Ѵ.


    Ʈ . ǻ Ʈ ġ ̳ ä Ÿ Ǵ µ Ѵ.

NDS(NOVELL DIRECTORY SERVICE)
    ڳ ý Ʈ ҽ ̽ȭ ̴.
    WAN Ʈ WAN ӵ Ű
    NDS ̽ лŰ鼭 . 뺧 ݿ 4.X ⺻
    ž ִ 丮 .

WAN(WIDE AREA NETWORK)
     ġǴ Ʈμ, 밳 ȣƮ
     Ѵ. ϴ 찡
    , ӵ Ư پϴ.

Ʈ
     ü ϰ ִ Ʈ Ϻα ̿ϴ ν
    ͳݿ ϰ ִ X Ѵ. ó ڰ
    ƴ϶ ȿ , ó, . ڰ
    ۺϰ ִ. ũ׷ Ʈ ϴ ɼ
     ڴ ̿ κ ڿ
    .

SNMP(SIMPLE NETWORK MANAGEMENT PROTOCOL)
    TCP/IP ȯ濡 Ʈ . ó SNMP
    Ʈ Ʈ ʿ䰡 ִ.

NMS
    Ʈ Ȳ ϰ ˷ִ

PING(PACKET INTERNET GROPER)
     PC ٸ Ʈ ƴ Ȯϴ
    α׷. ̿ Ʈ θ Ȯ.

OSI(OPEN SYSTEM INTERCONNECTION)
     ý۰ ȣ . ISO( ǥȭⱸ) ǥ
    . 7 ݱ ߴ ٸ ǻͳ
    Ʈ ϰ ϱ .

SOHO(Small Office Home Office)
    ұԸ ̳ .




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