What about NAT/NAPT?

• Problem statement:

  • NAPT == Network Address Port Translation
  • NAT/NAPT boxes sit between intra-nets and internet
  • How pervasive is NAT? Do IP QoS architectures really need to take them into account?

• Estimating NAPT pervasiveness:

  • NAPT modifies TCP/UDP port numbers
  • QuakeIII Arena clients consistently use UDP source port of 27960 (destination port depends on server)
  • Any client apparently attaching from port != 27960 can be assumed to represent an instance of NAPT along path