1. The New Waist of the Internet Hourglass Jonathan Rosenberg Cisco

2. The Internet has Changed NAT and Firewall Everywhere!

3. Implications Majority of NAT are NAPT which only works with UDP or TCP UDP/IP is the principle datagram service on the Internet now TCP/IP is the principle C/S service on the Internet now UDP/IP TCP/IP

4. What does it mean for Transport? If you want something that actually works on the Internet, you MUST encapsulate in UDP or TCP Things that start out as intranet technologies have a habit of migrating to the Internet –It is better to have one encapsulation rather than two The “overhead” for UDP encapsulation is negligible – most likely you needed ports and checksum anyway (DCCP, SCTP..)

5. What about IPv6? Migration is likely to make this problem persist –NAPT to enable v4 to v6 – will need extra 16 bits of address space –Dual stack – need encapsulation to work on v4 IPv6 NAT a distinct possibility anyway Why take the risk – just design ontop of UDP