The document discusses network address translation (NAT) and its implications. It describes how NAT allows multiple devices behind a NAT to appear as a single external IP address. It also discusses carrier grade NAT, which is implemented by internet service providers, and the challenges it poses for applications that require multiple connections or low latency connections between users. The document notes that as more internet-connected devices and applications are used per household, the limited supply of IPv4 addresses will be further strained by large internet providers.

2. NATs Good, Bad, and Complicated How your ISP plans to &quot;Help” you, and break the Internet Cullen Jennings <fluffy@cisco.com>

6. NAT Traversal

7. The Problem Cullen cisco.com skype.com Jonathan SIP RTP INVITE INVITE INVITE RTP

12. NATs, Carriers, And you

15. IPv4 Completion [Graphs as of Nov 2008 from www.potaroo.net]

17. Good News / Bad News