1. Rethink the design of the Internet CSCI 780, Fall 2005

2. E2E argument is great Complexity of core network is reduced, easy to upgrade Generality of network makes new applications easy to add Increases applications ’ reliability

3. Moving away from E2E Operation in an untrustworthy world Enforce ‘ good ” behavior More demanding applications Streaming audio and video ISP service differentiation Enhanced service is limited to one ISP Third-party involvement Interpose between the two ends Less sophisticated users

4. Technical responses Different forms of E2E argument Core (in the network) Edge (on or attached to the network) Modify the end-host Sometimes it does not work More functions to the network Firewall, traffic filter NAT box Packet labels (marking)

5. Trends at application layer Insert intermediary into data path due to performance or security reasons Anonymizing senders Content (layer-7) filtering Content caches (Web proxy, CDN) Application requirements become more complex

6. Current Internet is changing Rise of new players Commercial ISPs (Internet Service Providers) Tussle between ISPs Erosion of trust Security issues (global communication with local trust)

8. Two tenets valued but disobeyed Each Internet entity has a global identifier that allows others to reach it Network elements should not violate network layering

9. Middle-box violates tenets Network address translator (NAT) Pros: expands the IPv4 address space; address isolation Cons: p2p fails to work; layer violation; complicate new protocol or application design;

11. Private IP address IANA (Internet Assigned Numbers Authority) has reserved three blocks of the IP address space for private internets: 10.0.0.0 - 10.255.255.255 (10/8 prefix) 172.16.0.0 - 172.31.255.255 (172.16/12 prefix) 192.168.0.0 - 192.168.255.255 (192.168/16 prefix)  First is a single class A network number, second block is a set of 16 contiguous class B network numbers, third block is a set of 256 contiguous class C network numbers.

12. Delegation-oriented architecture (DOA) Goal: retain the functionality of middle- box, but eliminate their dangerous side- effect Approach: Provide a globally unique identifier in a flat namespace (160-bit EIDs) Explicit delegation