Network Devices - CompTIA A+ 220-1101 - 2.2

00:18:44
https://www.youtube.com/watch?v=1cS5JPULDdY

Ringkasan

TLDR该视频深入探讨了数据中心中的各种网络设备，包括路由器、交换机及其种类（管理和无管理）、接入点、补丁面板和防火墙等。路由器转发不同子网之间的流量，而交换机则在同一局域网内基于MAC地址转发信息。接入点则用于将无线信号与有线网络连接。视频也描述了补丁面板在电缆管理中的重要性，以及防火墙如何在网络中保障安全。此外，介绍了以太网供电（PoE）技术，能够通过以太网线为设备供电。最后，提到网络接口卡（NIC）在设备连接中的重要作用。

Takeaways

  • 🖥️ 路由器用于转发不同子网的流量。
  • 🔌 交换机基于MAC地址转发数据。
  • 📶 接入点连接无线和有线网络。
  • 🔧 管理交换机具备更多配置选项。
  • 🛠️ 补丁面板方便网络电缆管理。
  • 🔒 防火墙保护网络数据安全。
  • ⚡ Power over Ethernet (PoE) 实现通过电缆供电。
  • 📡 网络接口卡用于连接设备到网络。

Garis waktu

  • 00:00:00 - 00:05:00

    在数据中心中，有多种网络通信系统，包括路由器和交换机。路由器负责根据IP地址转发不同子网之间的流量，而交换机则基于MAC地址在局域网内部转发流量。路由器和交换机的理解对于考试学习至关重要，尤其是如何在不同网络使用这些设备的场景。

  • 00:05:00 - 00:10:00

    访问点提供无线网络连接，并作为有线和无线网络之间的桥梁。它不同于路由器，主要负责在无线网络与有线网络之间转发流量。通过使用配线架，可以便于连接和管理网络设备。当更换工作空间时，配线架使修改连接变得简单高效，避免了过多的电缆管理问题。

  • 00:10:00 - 00:18:44

    传统的防火墙能够基于IP地址和端口号控制流量，而现代防火墙还能理解应用层流量。随着技术的发展，像PoE这样的技术使得通过以太网电缆供电成为可能，许多设备如摄像头和无线接入点都能通过这种方式供电，而不同的PoE标准提供了从15W到71W的变更。

Peta Pikiran

Video Tanya Jawab

  • 路由器和交换机的主要区别是什么？

    路由器使用IP地址转发流量，而交换机使用MAC地址进行流量转发。

  • 什么是管理和无管理交换机？

    管理交换机提供更多配置选项，如VLANs，而无管理交换机则仅提供基本的连接功能，没有配置选项。

  • 接入点有什么功能？

    接入点提供无线连接，是将无线网络与有线网络连接的桥梁，并不是路由器。

  • 补丁面板的作用是什么？

    补丁面板帮助组织和管理网络布线，方便更改连接而无需重新布线。

  • 什么是PoE？

    PoE指通过以太网线为设备供电，简化布线，常用于接入点和监控摄像头。

  • 什么是DMARC？

    DMARC是划分服务提供商与用户内部网络责任的界限点。

  • 什么是网络接口卡（NIC）？

    NIC是用于提供与以太网或其他网络连接的设备，通常内置于设备中或作为扩展卡插入。

  • DSL 和电缆调制解调器有什么区别？

    DSL 与电缆调制解调器使用不同的信号传输方式，DSL多用于电话线，而电缆调制解调器用于有线电视线路。

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Gulir Otomatis:
  • 00:00:02
    if you walk in a data center for any
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    organization you'll find many many
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    different types of systems that are used
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    for network communication sometimes
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    these are single use devices like this
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    switch or it may be a device that
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    combines functionality for example the
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    soho routers that we'd normally use in
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    our home are both switches routers and
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    wireless access points all in one device
  • 00:00:23
    for the purposes of your exam studies
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    you should understand what these devices
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    are and in what circumstances you should
  • 00:00:29
    use these devices on your network
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    a router is a device that forwards
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    traffic between different ip subnets the
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    router uses the ip address that's within
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    the packet to determine what the next
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    hop might be on its way to the final
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    destination because this routing takes
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    place at layer 3 of the osi model we
  • 00:00:48
    often refer to these as layer 3 devices
  • 00:00:51
    and if we have a router that can be
  • 00:00:52
    configured inside of a switch you'll see
  • 00:00:55
    those devices referred to as layer 3
  • 00:00:57
    switches although routers can certainly
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    connect ipsubnets that are using the
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    same topology it's also common to use
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    routers to connect different types of
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    networks together for example the
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    interfaces on a router might connect lan
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    wan copper and fiber connections all in
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    one single device
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    another common infrastructure device is
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    a switch if you're using a copper cable
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    to plug in a laptop or desktop computer
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    then you're commonly plugging directly
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    into a switch a router commonly forwards
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    traffic based on the destination ip
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    address that's within a packet a switch
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    determines where traffic should be
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    forwarded based on the destination mac
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    address inside of that frame this is
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    also a device that's able to forward
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    traffic at very high rates of speed
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    because a lot of those forwarding
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    decisions are based in the hardware of
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    the device itself many switches have an
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    application specific integrated circuit
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    or an asic which allows for very fast
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    throughput if you have a switch that's
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    in the core of an enterprise network
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    there could be tens or even hundreds of
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    interfaces on that switch and many
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    switches will also add additional power
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    to the switch connection using poe or
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    power over ethernet
  • 00:02:08
    and as we mentioned earlier if you
  • 00:02:10
    happen to have a switch that has the
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    ability to turn on additional routing
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    functionality we often refer to that as
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    a layer 3 switch or a multi-layer switch
  • 00:02:20
    if you were to purchase a switch for
  • 00:02:22
    your home from a local or online
  • 00:02:24
    retailer that switch probably doesn't
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    have a lot of functionality it is simply
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    connecting all of these devices together
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    if you've simply powered the switch up
  • 00:02:32
    and there's no configuration options on
  • 00:02:34
    the switch at all then you're probably
  • 00:02:36
    using an unmanaged switch unlike
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    switches that you might find in an
  • 00:02:40
    enterprise an unmanaged switch gives you
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    very few configuration options for
  • 00:02:45
    example you can't configure any vlans on
  • 00:02:47
    an unmanaged switch all of the devices
  • 00:02:49
    that you're connecting to an unmanaged
  • 00:02:51
    switch would all effectively be on the
  • 00:02:54
    same vlan there's also very little
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    integration with other protocols or
  • 00:02:58
    other devices in an earlier video we
  • 00:03:00
    described the simple network management
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    protocol or snmp network administrators
  • 00:03:05
    often use snmp to query these devices on
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    their network to check for performance
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    or any types of errors an unmanaged
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    switch commonly has no snmp capabilities
  • 00:03:15
    so although you could connect it to your
  • 00:03:17
    network there would be no way to pull it
  • 00:03:19
    or query that device for performance
  • 00:03:21
    information but if all you need is a
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    simple connectivity device that you can
  • 00:03:25
    use to connect all of your systems
  • 00:03:27
    together you can probably get an
  • 00:03:28
    unmanaged switch at a relatively low
  • 00:03:31
    cost
  • 00:03:32
    if you're purchasing a switch for an
  • 00:03:34
    office or a larger organization you're
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    probably going to get a switch that is a
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    managed switch this is one that provides
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    additional capabilities especially for
  • 00:03:43
    someone who needs to constantly monitor
  • 00:03:45
    and confirm that this device is working
  • 00:03:47
    as expected for example a managed switch
  • 00:03:50
    may allow you to configure different
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    interfaces to be on completely different
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    ip subnets or what we call vlans or
  • 00:03:56
    virtual lans these switches might also
  • 00:03:58
    have configuration options to prioritize
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    traffic so you may be able to set voice
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    over ip traffic to have a higher
  • 00:04:04
    priority than file transfer traffic it's
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    very common for organizations to have
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    multiple switches that they would
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    connect to their network and one way
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    that you could prevent loops between all
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    of those switches is by enabling
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    spanning tree protocol or stp to have
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    stp as a configuration option on your
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    switch you would probably need to have a
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    managed switch some managed switches
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    will allow you to perform port mirroring
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    where you can take traffic from one port
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    that's on the switch and copy all of
  • 00:04:31
    that traffic to a different port on the
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    switch ideally to plug in a protocol
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    analyzer to be able to view all of those
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    packets traversing the network this is
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    commonly used for troubleshooting or
  • 00:04:42
    packet analysis and not something you
  • 00:04:44
    would usually find on an unmanaged
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    switch and as we've mentioned a managed
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    switch can also include a number of
  • 00:04:50
    different capabilities such as enabling
  • 00:04:52
    simple network management protocol or
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    snmp
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    if you're in the office or you're
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    walking through another place of
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    business look at the ceiling and see if
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    you see a device like this this is an
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    access point and provides wireless
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    connectivity for the local network this
  • 00:05:08
    is not a router that you might find in a
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    soho device at your small office or home
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    office this is a device that only
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    provides a link between the wireless
  • 00:05:17
    network and the wired network you'll
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    sometimes hear these devices referred to
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    as a bridge because they are simply
  • 00:05:23
    bridging or extending that wired
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    connection into a wireless connection
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    this is not a device that is routing
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    between subnets and it's not performing
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    any type of network address translation
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    it's simply bridging people on the
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    wireless network to the folks that are
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    on the wired network an access point
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    makes forwarding decisions based on the
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    destination mac address which is
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    identical to the way that a switch
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    forwards information the access point
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    examines the destination mac address and
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    determines if that mac address is on the
  • 00:05:51
    wireless network or if it should send
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    that information to the wired network
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    one of the challenges with connecting
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    many many people in a work environment
  • 00:06:01
    to the network is that there are a lot
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    of cables that have to be managed in
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    this diagram we have a number of people
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    that are sitting at their desk on the
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    floor of the building and you can see
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    there are a lot of cables we have a
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    cable from every desk that is going back
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    to a central wiring closet on that floor
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    in that wiring closet is a patch panel
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    we first would connect all of those
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    devices to this patch panel and that run
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    is a permanent run once somebody is
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    connected from their desk to the patch
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    panel we don't tend to move that cable
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    going forward on the other side that
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    patch panel can be connectors like rj45
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    connectors and we would then extend
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    those rj45 connectors to interfaces that
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    may be on a switch inside of that wiring
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    closet this allows us to connect folks
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    that are on their desk all the way back
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    to the main infrastructure of a
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    particular network there may be times
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    when somebody is moving between desks or
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    perhaps they have a new person that's
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    hired who's sitting in a new desk in
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    those scenarios you may have to move
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    someone from a connection on one switch
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    to a connection on another switch if
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    this was all one single cable then you
  • 00:07:05
    would have to start moving cables inside
  • 00:07:07
    of your wiring closet to try to properly
  • 00:07:10
    place where they should be connected but
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    with the patch panel in place you simply
  • 00:07:14
    disconnect from one switch and you
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    connect that particular port on the
  • 00:07:18
    patch panel to a different switch this
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    is a much shorter cable it's a cable
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    that's already labeled so you know
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    exactly which desk it's going to and
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    it's a change that you can make
  • 00:07:27
    relatively quickly
  • 00:07:28
    here is the rj45 side of a patch panel
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    that's in someone's wiring closet if you
  • 00:07:34
    look closely behind the patch panel you
  • 00:07:36
    can see all of the cable runs that are
  • 00:07:38
    coming from the desks and then you can
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    see the rj45 connectors on the front
  • 00:07:42
    that are ultimately connecting to a
  • 00:07:43
    switch
  • 00:07:44
    this means that nothing is going to
  • 00:07:46
    change with the wiring between a user's
  • 00:07:48
    workstation and the closet because all
  • 00:07:50
    of that is punched down and permanently
  • 00:07:52
    connected to the back of this patch
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    panel when you need to make a change you
  • 00:07:55
    simply move the cable that's on the
  • 00:07:57
    front of the patch panel which certainly
  • 00:07:59
    limits the scope of any problems that
  • 00:08:01
    might occur during one of these changes
  • 00:08:03
    if you have a patch panel like this
  • 00:08:05
    which uses rj45 connectors you don't
  • 00:08:07
    even need any special cabling to make
  • 00:08:09
    that change you simply unplug the cable
  • 00:08:11
    move it to where it needs to be and plug
  • 00:08:13
    it into the new interface
  • 00:08:15
    here's the connection between a patch
  • 00:08:17
    panel and a switch this is the patch
  • 00:08:19
    panel on the top there are cables you
  • 00:08:21
    can't see that go back to the desk and
  • 00:08:23
    then there are smaller cables on the
  • 00:08:25
    front that connect from the patch panel
  • 00:08:27
    and extend that connection into an
  • 00:08:29
    interface on the switch
  • 00:08:32
    a traditional firewall is able to allow
  • 00:08:34
    or disallow traffic through your network
  • 00:08:36
    based on ip addresses and port numbers
  • 00:08:39
    since those tcp and udp ports operate at
  • 00:08:42
    layer 4 of the osi model it's common to
  • 00:08:44
    refer to firewalls like this as an osi
  • 00:08:47
    layer 4 device these days it's
  • 00:08:49
    increasingly common to see firewalls
  • 00:08:51
    that understand application layer
  • 00:08:54
    traffic and in those cases the firewall
  • 00:08:56
    would be a layer 7 device
  • 00:08:58
    some firewalls can also act as an
  • 00:09:01
    endpoint for an encrypted tunnel which
  • 00:09:03
    means that you can connect two sites
  • 00:09:05
    together across a public network like
  • 00:09:07
    the internet but all of the traffic
  • 00:09:09
    between those sites is encrypted
  • 00:09:11
    some firewalls can also act as a proxy
  • 00:09:13
    so if someone is browsing a site on the
  • 00:09:15
    internet the firewall will stop that
  • 00:09:17
    communication it will perform the
  • 00:09:19
    browsing for the user receive the
  • 00:09:21
    response from that device over the
  • 00:09:23
    internet examine and make sure that
  • 00:09:25
    nothing inside of that traffic may be
  • 00:09:27
    dangerous or malicious and then send the
  • 00:09:29
    results of that query back to the user
  • 00:09:32
    and in many cases and this is probably
  • 00:09:34
    the case for the small soho type routers
  • 00:09:37
    you use at home this firewall can also
  • 00:09:39
    act as a router this device is making
  • 00:09:42
    forwarding decisions based on the
  • 00:09:43
    destination ip address therefore it's
  • 00:09:46
    acting as an osi layer 3 device in many
  • 00:09:49
    environments the firewall is the device
  • 00:09:51
    that is connected directly to the
  • 00:09:52
    internet and so using that also as a
  • 00:09:55
    router allows you additional
  • 00:09:56
    functionality for forwarding traffic
  • 00:10:00
    if you're using a desktop computer or a
  • 00:10:02
    laptop computer you may be accustomed to
  • 00:10:04
    connecting to a power source to be able
  • 00:10:06
    to use those devices but some devices
  • 00:10:08
    allow you to power that system through
  • 00:10:11
    the ethernet cable that's already
  • 00:10:12
    connecting to the device we refer to
  • 00:10:14
    that type of power as power over
  • 00:10:16
    ethernet or poe this allows you to run a
  • 00:10:20
    single wire to the device that will not
  • 00:10:22
    only be able to transfer data but also
  • 00:10:24
    used as the power source for that device
  • 00:10:27
    you often see poe used with access
  • 00:10:29
    points cameras and anything else where
  • 00:10:32
    power may be difficult to run to that
  • 00:10:34
    device
  • 00:10:35
    often this power is coming directly from
  • 00:10:37
    the switch and in those cases we refer
  • 00:10:39
    to that as an in span if your switch
  • 00:10:42
    doesn't support poe then you'll need
  • 00:10:44
    something in the middle of that
  • 00:10:45
    connection that will add power to the
  • 00:10:47
    ethernet cable we refer to these as poe
  • 00:10:50
    injectors and this is often referenced
  • 00:10:53
    as a mid-span this is a poe injector on
  • 00:10:56
    my network that powers a camera you can
  • 00:10:58
    see the connection from the cameras
  • 00:11:00
    plugging into the poe or the data
  • 00:11:02
    connection and then i have another cable
  • 00:11:04
    that's connecting back to a switch that
  • 00:11:06
    doesn't support poe once my switch and
  • 00:11:09
    camera are connected and i power up the
  • 00:11:11
    injector the camera now has the power it
  • 00:11:13
    needs to be able to operate
  • 00:11:15
    most switches will identify what
  • 00:11:17
    interfaces can support something like
  • 00:11:20
    poe on this switch for example you can
  • 00:11:22
    see that it's a common eight port
  • 00:11:24
    ethernet switch and you can see that
  • 00:11:26
    anywhere it has the blue color across
  • 00:11:28
    the top it will support poe so ports 1
  • 00:11:32
    through 8 will support poe port 9 looks
  • 00:11:34
    like it's commonly used as an uplink
  • 00:11:36
    port and since it does not have that
  • 00:11:38
    blue line this interface does not
  • 00:11:40
    support poe
  • 00:11:42
    different devices need different types
  • 00:11:44
    of power and there are different
  • 00:11:46
    standards for poe depending on what type
  • 00:11:48
    of switch you might be using the
  • 00:11:50
    traditional or original style of poe is
  • 00:11:54
    specifically called the ieee 802.3 af
  • 00:11:57
    from 2003. this is the original poe
  • 00:12:01
    specification that has now been rolled
  • 00:12:03
    into the standard 802.3 ethernet
  • 00:12:06
    standard this provides 15.4 watts of dc
  • 00:12:09
    power with 350 milliamps as the max
  • 00:12:13
    current we improved poe through the
  • 00:12:15
    years and in 2009 we introduced ieee
  • 00:12:18
    802.380
  • 00:12:20
    this has also been wrapped into the
  • 00:12:22
    802.3 standard and it provides
  • 00:12:25
    additional power 25.5 watts of dc power
  • 00:12:29
    with a maximum milliamp current of 600
  • 00:12:32
    milliamps and one of the more modern poe
  • 00:12:35
    standards is the poe plus plus or the
  • 00:12:38
    ieee 802.3bt
  • 00:12:41
    when we're providing 51 watts with 600
  • 00:12:43
    milliamps of max current we refer to
  • 00:12:45
    this as a type 3 type 4 poe plus plus is
  • 00:12:49
    71.3 watts with 960 milliamps as the max
  • 00:12:53
    current this was a standard designed to
  • 00:12:55
    work with 10 gigabit per second ethernet
  • 00:12:58
    and provide power for those 10 gig
  • 00:13:00
    devices
  • 00:13:02
    before there were switches we commonly
  • 00:13:04
    used hubs to be able to connect all of
  • 00:13:06
    the devices on our network sometimes
  • 00:13:08
    you'll hear a hub referred to as a
  • 00:13:10
    multi-port repeater that's because hubs
  • 00:13:12
    are not very intelligent devices any
  • 00:13:15
    data that's going into one interface on
  • 00:13:17
    this hub will automatically be copied
  • 00:13:19
    and sent to all of the other interfaces
  • 00:13:22
    on this hub as you can imagine this is
  • 00:13:24
    not the most efficient way to
  • 00:13:26
    communicate and on top of that we're not
  • 00:13:28
    able to run any full duplex
  • 00:13:29
    communication to a hub so all of the
  • 00:13:32
    devices plugged into this hub will
  • 00:13:33
    operate at half duplex
  • 00:13:35
    since everything is being retransmitted
  • 00:13:38
    to every other interface on this device
  • 00:13:41
    as you put more of a load and add more
  • 00:13:43
    devices to the network the performance
  • 00:13:46
    of this device tends to get slower and
  • 00:13:48
    slower that's one of the reasons we
  • 00:13:50
    decided to change from a hub-based
  • 00:13:52
    network to something more intelligent
  • 00:13:54
    like a switch-based network these
  • 00:13:56
    devices are a bit outdated for our
  • 00:13:58
    modern networks and if you do find a hub
  • 00:14:00
    you'll find that they are only available
  • 00:14:02
    in 10 megabit and 100 megabit speeds
  • 00:14:05
    these are not devices that you would
  • 00:14:06
    find new these are probably only
  • 00:14:08
    available on a secondary or used market
  • 00:14:12
    if you're using the same cable for your
  • 00:14:14
    cable television as your internet
  • 00:14:16
    connection then you probably have a
  • 00:14:18
    cable modem in your home this allows you
  • 00:14:21
    to communicate over what we call
  • 00:14:23
    broadband communication because there
  • 00:14:25
    are multiple frequencies of traffic
  • 00:14:27
    being used over a single wire this means
  • 00:14:30
    that we can have video signals for our
  • 00:14:32
    television we can connect our phone
  • 00:14:34
    lines into this cable modem and of
  • 00:14:36
    course it can be used for internet data
  • 00:14:39
    there's a standard for sending data over
  • 00:14:41
    these cable networks and that standard
  • 00:14:43
    is called docsis that stands for data
  • 00:14:45
    over cable service interface
  • 00:14:47
    specification many cable modems can
  • 00:14:50
    support higher speeds up to one gigabits
  • 00:14:52
    per second and the total speeds
  • 00:14:54
    available to you will be dependent on
  • 00:14:56
    your service provider there are usually
  • 00:14:57
    multiple services available on these
  • 00:14:59
    networks and when you connect the cable
  • 00:15:01
    you can either connect to the data
  • 00:15:02
    that's on the internet side this
  • 00:15:04
    particular cable modem also has analog
  • 00:15:06
    telephone connections for any voice
  • 00:15:09
    communication
  • 00:15:11
    if you're not using your cable company
  • 00:15:12
    for internet connectivity you may be
  • 00:15:14
    using the traditional telephone company
  • 00:15:16
    to provide that connection and usually
  • 00:15:18
    that's done through a dsl modem often
  • 00:15:21
    this is technically an adsl modem which
  • 00:15:24
    stands for asymmetric digital subscriber
  • 00:15:26
    line and it uses the same telephone
  • 00:15:29
    lines that we've always used for our
  • 00:15:31
    analog telephone the reason that dsl is
  • 00:15:34
    asymmetric is because the speeds for
  • 00:15:36
    downloading is usually much faster than
  • 00:15:38
    the speeds for uploading there's also
  • 00:15:41
    often a distance limitation with dsl
  • 00:15:43
    before the signal gets so weak that
  • 00:15:45
    you're not able to receive any of the
  • 00:15:47
    data that's usually around 10 000 feet
  • 00:15:50
    from the central office or the co
  • 00:15:53
    it's common to see speeds with dsl that
  • 00:15:55
    range from 52 megabit down and 16
  • 00:15:58
    megabit up but you can find larger and
  • 00:16:00
    faster dsl implementations depending on
  • 00:16:03
    the capabilities from your provider if
  • 00:16:05
    you are closer to the co you also tend
  • 00:16:08
    to get much faster throughput than if
  • 00:16:09
    you're farther away
  • 00:16:12
    and if you're not connecting to the
  • 00:16:13
    internet using copper cable or telephone
  • 00:16:15
    lines then you may be connecting with
  • 00:16:17
    fiber to connect to the fiber network
  • 00:16:19
    you need an ont or an optical network
  • 00:16:22
    terminal which is a device that's
  • 00:16:24
    usually connected outside of your home
  • 00:16:25
    or your premise this is connecting an
  • 00:16:28
    isp fiber network and converting it into
  • 00:16:31
    signals like copper ethernet that can be
  • 00:16:33
    used inside of your home this ont is
  • 00:16:35
    usually connected to the outside of your
  • 00:16:38
    building and it usually delineates the
  • 00:16:40
    isp's network from your own internal
  • 00:16:43
    network we refer to this delineation as
  • 00:16:46
    a demarcation point or a d mark
  • 00:16:49
    sometimes this dmarc is located in your
  • 00:16:51
    data center itself or if you're at home
  • 00:16:53
    it's located on the outside of your home
  • 00:16:56
    it's important that a dmarc exists so
  • 00:16:58
    you know what the responsibilities are
  • 00:17:00
    for each different party you know that
  • 00:17:02
    any of the wiring on the inside of your
  • 00:17:04
    house is your responsibility up to the
  • 00:17:07
    point of that d mark and then anything
  • 00:17:09
    outside of that d mark is the
  • 00:17:11
    responsibility of the service provider
  • 00:17:14
    this is a closer look of this ont this
  • 00:17:16
    is the fiber connection coming in from
  • 00:17:18
    the street you can see the fiber label
  • 00:17:20
    is placed there you can see this device
  • 00:17:22
    has outputs for data which is an
  • 00:17:24
    ethernet connection you can plug in
  • 00:17:26
    analog telephone to this device as well
  • 00:17:28
    and there's an f connector here for the
  • 00:17:30
    cable connection that you plug into your
  • 00:17:32
    television
  • 00:17:34
    if you are connecting to a copper
  • 00:17:36
    ethernet connection you're using a
  • 00:17:38
    network interface card to provide that
  • 00:17:40
    connectivity or a nic all of the devices
  • 00:17:43
    we've discussed so far that are
  • 00:17:44
    connecting to a wired ethernet
  • 00:17:46
    connection have a network interface card
  • 00:17:48
    inside of them this is a network
  • 00:17:50
    interface card you would plug into a
  • 00:17:52
    server and this card has four separate
  • 00:17:54
    ethernet connectors on the back but if
  • 00:17:56
    you have a laptop or a desktop computer
  • 00:17:58
    with an ethernet interface that also is
  • 00:18:01
    a network interface card there are also
  • 00:18:04
    network interface cards for other types
  • 00:18:06
    of topologies if you're plugging into a
  • 00:18:08
    wide area network serial connection or
  • 00:18:10
    you have a wireless interface those also
  • 00:18:13
    have network interface cards these are
  • 00:18:15
    sometimes built into the motherboard or
  • 00:18:17
    it may be a separate adapter that you
  • 00:18:19
    can plug into an expansion slot and
  • 00:18:21
    increase the capabilities of your device
  • 00:18:23
    so whether you need copper connectivity
  • 00:18:25
    fiber connectivity or anything in
  • 00:18:27
    between you will need a network
  • 00:18:29
    interface card on your device to make
  • 00:18:31
    that connection to the rest of the
  • 00:18:33
    network
  • 00:18:43
    you
Tags
  • 网络设备
  • 路由器
  • 交换机
  • 接入点
  • 补丁面板
  • 防火墙
  • 以太网供电
  • 网络接口卡
  • DSL
  • 电缆调制解调器