"portability" of IP Addresses

Alan Hannan alan at mindvision.com
Fri Jan 31 03:30:42 UTC 1997


  I am curious for perspectives on the use of non portable
  IP addresses for multi-homing.

  Can a provider forbid their customer from announcing allocated
  networks to another provider?

  Assume the following situation:

  ISP A gets customer C to sign an agreement for service.  ISP A
  allocates network A.B.C.0/20 to customer C.  A.B.C.0/20 is a
  subnet of CIDR block A.B.0.0/16, allocated to ISP A by our friends
  at the InterNIC as a non-portable address space.

  It should be obvious that customer C is locked in for Y years, and
  is paying D dollars per year.

  Ok.  With me so far?  :-)

  So, customer C goes to ISP B, and says, I'd like to buy service
  from you, and announce network A.B.C.0/20 to you.

  Customer C informs ISP A, for niceties, and ISP A informs them
  that they cannot do this.  If Customer C wants to announce routes 
  to both  ISP A and ISP B they must renumber.  (source of IP
  Addresses for renumbering is left to your imagination, ISP A, B, or 
  direct from InterNIC.)

  Can ISP A enforce this decree?  I realize it depends upon the
  contract, but let's assume the contract doesn't specify.

  I would think that ISP A would not mind Customer C announcing the
  network to ISP B, but would make it clear that if Customer C stops
  the relationship with ISP A, then ISP A would reclaim the address

  Is this intelligent use of IP Address space, draconian practices
  to discourage multihoming, or probably a miscommunication?


Alan Hannan
email: alan at mindvision.com.

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