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Multi-homed nodes

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• IP address assignment
  • Recall:

    The network prefix of an IP address for all nodes in the same IP domain are equal (same prefix !!)

    Example:

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• IP hosts attached on multiple IP networks
  • Fact:

    Some IP hosts (routers !!!) are located on 2 or more IP-networks.

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  • In fact:

    A routers is always attached to 2 or more IP-networks:

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  • Multi-homed IP node:

    Multi-homed node = A node that is attached to multiple IP networks

  • Fact:

    A nulti-homed host/node will have: multiple IP addresses (one IP address per IP network) (Because the network prefix of the networks are different)

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  • Note:

    It's best to think that IP addresses are assigned to: The network interfaces of a node (instead of being assigned to the node itself) Graphically:

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• Unix command to find out the IP addresses of a host
  • Try this:

    host www.yahoo.com fd-fp3.wg1.b.yahoo.com has address 98.139.183.24 fd-fp3.wg1.b.yahoo.com has address 98.139.180.149