public vs private data network

Discussion in 'Cisco' started by jonnah, Apr 11, 2005.

  1. jonnah

    jonnah Guest

    hi all,

    what is the difference between public and a private data network? am I
    correct in assuming that if you use a *public* data network to connect
    your remote offices with your branch offices, you either use the
    Internet as the Public DN or frame relay (as the Public DN of a telco)
    but if you use leased lines or pt to pt links, then is it considered
    as a *private* data network? (since you're not sharing the links with
    others) if anybody knows, please enlighten me

    thanks!
     
    jonnah, Apr 11, 2005
    #1
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  2. jonnah

    Brian Guest

    Private vs Public refers to the IP addressing scheme. You can use
    either globally routed IP's (public) or private IP's
    10.0.0.0 - 10.255.255.255 (10/8 prefix)
    172.16.0.0 - 172.31.255.255 (172.16/12 prefix)
    192.168.0.0 - 192.168.255.255 (192.168/16 prefix).
    See RFC 1918 for more details.
    http://www.faqs.org/rfcs/rfc1918.html
     
    Brian, Apr 11, 2005
    #2
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  3. jonnah

    jonnah Guest

    I might have been misinterpreted in my question. I was asking public
    and private data networks in terms of wide area implementation of
    connecting geographically separated locations using telcos and not in
    terms of ip addressing scheme.
     
    jonnah, Apr 12, 2005
    #3
  4. :what is the difference between public and a private data network? am I
    :correct in assuming that if you use a *public* data network to connect
    :your remote offices with your branch offices, you either use the
    :Internet as the Public DN or frame relay (as the Public DN of a telco)
    :but if you use leased lines or pt to pt links, then is it considered
    :as a *private* data network? (since you're not sharing the links with
    :eek:thers) if anybody knows, please enlighten me

    Pretty much. If a random person around the world can get packets
    to your security gate then you are on a public data network.
    If only a closed list of places can get to your security gate,
    and you can't get out either then you are on a private data network.

    In between would be semi-private networks that have clouds
    of accessible devices and security gateways to public networks.
    For example, a research network might allow public email in
    and might allow insiders a wide variety of outward accesses,
    but the basic security controls might be far away from
    most of the member systems.

    To really be considered a private network in the traditional
    PSTN sense, there can't be -any- cross-border traffic possible
    through the network facilities.
     
    Walter Roberson, Apr 12, 2005
    #4
  5. jonnah

    Herb Martin Guest

    No, your question was clear, and your own explanation
    was close on -- Walter's (elsewhere) this thread might
    have amplified on it a bit, but notice that as he introduced
    "semi-private" (or was it "semi-public" <grin>) that these
    concept are somewhat dependent on context and point of
    view.
     
    Herb Martin, Apr 13, 2005
    #5
  6. jonnah

    jonnah Guest

    So is it safe to say that if I use leased lines to connect my sites
    it's on a private network, if I use the frame relay network of a telco
    to connect the sites its a semi-private network and if I use the
    internet (via ip vpn) to connect my sites its on a public network....?

    thanks
     
    jonnah, Apr 14, 2005
    #6
  7. :So is it safe to say that if I use leased lines to connect my sites
    :it's on a private network, if I use the frame relay network of a telco
    :to connect the sites its a semi-private network and if I use the
    :internet (via ip vpn) to connect my sites its on a public network....?

    I have never been involved with a FR installation, but my
    understanding is that FR can be configured as either public
    or private. That is, if you can find a carrier to serve
    all of your sites, that they can configure the FR for private
    access (e.g., using VLANs or MLPS), but that FR could also
    be configured to an ISP's gateway to the internet (which would
    make it public.)

    Semi-private (or semi-public) is not a generally accepted term:
    I used it for lack of anything better. I just didn't want to
    be "black and white" about it when there is clearly opportunity
    for hybrids. Suppose for example that you used a FR cloud to
    link your sites, and you installed a firewall that allowed in
    public only access to your web servers, with the firewall
    transparently redirecting into the appropriate location within
    the cloud. As far as the things other than the web servers
    are concerned, the cloud would be "private" because no public
    packets can get there and they can't get out -- but the
    web servers would be public... and possibly thousands of
    miles from the firewall, reached through the FR cloud.
     
    Walter Roberson, Apr 14, 2005
    #7
  8. jonnah

    Ian M Guest

    Jonnah,

    As an earlier post said, it's context sensitive. The Internet, PSTN (&
    often wireless) are public. LAN with all wires inside your buiding
    where you can see them is private. Anything else depends on context,
    sensitivity of data being carried, who you're talking to, etc; and could
    be one or the other (semi- is not used).

    Many consider leased lines private. But they can terminate in outside
    cabinets with generic keys; they're patched in exchanges by telco techs
    that can make mistakes, or be partial to bribes. Though maybe your data
    isn't precious enough to worry.

    If your interest is data confidentiality (e.g. any volume of financial
    transactions or personal data) you'll assume that any cable (incl. all
    leased lines & fibre) that you can't see, someone else can, and encrypt
    what's on it.

    HTH,
    Ian
     
    Ian M, Apr 14, 2005
    #8
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