What Makes for a Successful Protocol? Presented By: Nigel Medforth

Agenda  What is a successful protocol?  Success Dimensions  Initial Success Factors  “Wildly” Successful Protocols  “Wild” Success Factors  What is a failed protocol?  Mitigating failure

What is a Successful Protocol? A protocol is considered successful if: A protocol is considered successful if:  It meets the original design specifications  It is “widely deployed” Dependant on the desired deployment scope Dependant on the desired deployment scope E.g., TCP, BGP, DHCP, NAT, etc… E.g., TCP, BGP, DHCP, NAT, etc…

Success Dimensions

Initial Success Factors 1.Positive Net Value  Potential Costs  Hardware costs  Operational interference  Training  Business model impact  Potential benefits  Lowers existing costs  Provides new desired features  Provides incremental improvements

Initial Success Factors

Other Initial Success Factors 2.Allows Incremental Deployment 3.Open code availability 4.No usage restrictions 5.Open specification availability 6.Open maintenance processes 7.Good technical design

“Wildly” Successful protocols

“Wildly” Successful Protocols Greatly exceeds its intended scale and/or purpose; Greatly exceeds its intended scale and/or purpose; Does not affect initial success Does not affect initial success E.g., HTTP, IPv4, ARP E.g., HTTP, IPv4, ARP

“Wild” Success Factors 1.Extensible 2.No hard scalability bounds 3.Threads sufficiently mitigated

Downside of “Wild” Success Undesirable side effects when adding new features Undesirable side effects when adding new features Performance problems Performance problems Design limitations Design limitations High value target for hackers High value target for hackers

Case of WEP Stream cipher algorithm using RC4 Stream cipher algorithm using RC4 RC4 is a well-known but proprietary algorithm RC4 is a well-known but proprietary algorithm Many attacks exist, culminating with a method published in 2007 to break a 104 bit key within 40,000 packets (~60 seconds) Many attacks exist, culminating with a method published in 2007 to break a 104 bit key within 40,000 packets (~60 seconds) Yet this is still considered successful. Yet this is still considered successful.

Case of WEP Initial Success Factors: Initial Success Factors:  Positive net value: yes; provided security  Incremental deployability: yes  Open code availability: no, due to RC4  No usage restrictions: no  Open maintenance process: yes  Good technical design: no Wild success factors: Wild success factors:  Extensible: no  No hard scalability bounds: no  Threats sufficiently mitigated: no

What is a Failed Protocol? No mainstream implementation No mainstream implementation No deployment No deployment No use No use Typically takes 5 to 10 years to determine Typically takes 5 to 10 years to determine

Mitigating Failure Address a critical and imminent problem Address a critical and imminent problem Provide a “killer app” with low development costs Provide a “killer app” with low development costs Provide value for an existing unmodified applications Provide value for an existing unmodified applications Reduce purpose and/or scope Reduce purpose and/or scope Provide incentives Provide incentives

Questions?