Single IP Address Assignment - TCP-IP

This is a discussion on Single IP Address Assignment - TCP-IP ; I have several people from an ISP in one of a networking basics class. We were discussing some of the basics of the IP protocol. We were talking specifically about the process for leasing a block of IPs from ICANN ...

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Thread: Single IP Address Assignment

  1. Single IP Address Assignment

    I have several people from an ISP in one of a networking basics class.
    We were discussing some of the basics of the IP protocol. We were
    talking specifically about the process for leasing a block of IPs from
    ICANN for use in a network. One of the students from the ISP mentioned
    that their ISP leases to their DSL customers a single IP address for
    use on the WAN side of the router. I was unsure how this ends up
    working. He showed me the printout of the order and it shows a single
    public IP being leased with a subnet mask of 255.255.255.255.

    Usually for a routed connection, the subnet mask above indicates a host
    device in a network, correct? So, is the ISP treating these customers
    routers as part of one big network?

    Confused and hoping someone can shed some light on the situation.

    Keven


  2. Re: Single IP Address Assignment

    In article <1156985419.881638.110720@h48g2000cwc.googlegroups. com>,
    keven.denen@gmail.com wrote:

    > I have several people from an ISP in one of a networking basics class.
    > We were discussing some of the basics of the IP protocol. We were
    > talking specifically about the process for leasing a block of IPs from
    > ICANN for use in a network. One of the students from the ISP mentioned
    > that their ISP leases to their DSL customers a single IP address for
    > use on the WAN side of the router. I was unsure how this ends up
    > working. He showed me the printout of the order and it shows a single
    > public IP being leased with a subnet mask of 255.255.255.255.
    >
    > Usually for a routed connection, the subnet mask above indicates a host
    > device in a network, correct? So, is the ISP treating these customers
    > routers as part of one big network?
    >
    > Confused and hoping someone can shed some light on the situation.
    >
    > Keven


    What they probably do is assign a block of addresses to each DSLAM, so
    the routing tables on their backbone only have to deal with these
    aggregates. On the DSLAM itself there are presumably routes that
    associate each IP with a particular DSL customer (a PPPoE username).

    --
    Barry Margolin, barmar@alum.mit.edu
    Arlington, MA
    *** PLEASE post questions in newsgroups, not directly to me ***
    *** PLEASE don't copy me on replies, I'll read them in the group ***

  3. Re: Single IP Address Assignment

    Hello,

    keven.denen@gmail.com a écrit :
    > [...] One of the students from the ISP mentioned
    > that their ISP leases to their DSL customers a single IP address for
    > use on the WAN side of the router. I was unsure how this ends up
    > working. He showed me the printout of the order and it shows a single
    > public IP being leased with a subnet mask of 255.255.255.255.
    >
    > Usually for a routed connection, the subnet mask above indicates a host
    > device in a network, correct? So, is the ISP treating these customers
    > routers as part of one big network?


    A /32 mask usually indicates a point to point link, which is rather
    common on DSL lines using some form of PPP.

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