3Why the Hourglass Architecture? Why an internet layer?make a bigger networkglobal addressingvirtualize network to isolate end-to-end protocols from network details/changesWhy a single internet protocol?maximize interoperabilityminimize number of service interfacesWhy a narrow internet protocol?assumes least common network functionality to maximize number of usable networksWWW phone...SMTP HTTP RTP...TCP UDP…IPethernet PPP…CSMA async sonet...copper fiber radio...
4Why Am I Talking About Watching the Waist? Keynote is an opportunity for navel gazingIt happens on reaching middle age (me & IP)The IP layer is the only layer small enough for me to get my arms aroundI am worried about how the architecture is now being lost: the waste of the hourglassThe hourglass theme offers many bad puns
5Putting on Weight requires more functionality from underlying networks WWW phone...SMTP HTTP RTP...TCP UDP…IP + mcast+ QoS +...ethernet PPP…CSMA async sonet...copper fiber radio...requires more functionality from underlying networks
6Mid-Life Crisis doubles number of service interfaces WWW phone...SMTP HTTP RTP...TCP UDP…IP IP6ethernet PPP…CSMA async sonet...copper fiber radio...doubles number of service interfacesrequires changes above & belowmajor interoper-ability issues
7Oops! An Accident NATs & ALGs used to glue the broken pieces WWW phone...SMTP HTTP RTP...TCP UDP…IPethernet PPP…CSMA async sonet...copper fiber radio...NATs & ALGs used to glue the broken pieceslots of kinds of new glue being invented—ruins predictabilitysome apps remain broken, since repairs are incomplete
8Threat-ened by Youthsdanger : creeping dependencies on specific link-layers inhibit flexibility and evolutiondoesn’t fully supplant IP, so end up with complicated hybrid & two address plansWWW phone...SMTP HTTP RTP...TCP UDP…IP ATMethernetCSMA async sonet...copper fiber radio...
9The Youths’ Latest Trick WWW phone...SMTP HTTP RTP...TCP UDP…IPATMCIFethernet PPP…CSMA async sonet...copper fiber radio...cells-in-frames (CIF)shredded and bundled packetshope is that IP and frame-oriented media will fade awaygoal is a fatter waist
11Below-the-Waist Bulge mostly reinventing, badly, what IP already does (or could do):VLANsLANErouter bypass / NHRPtag-switching / MPLS (“layer 2.5”)lower layers mostly seem to just make IP’s job hardercells, circuits, QoS, multicast, large clouds, opaque clouds
12ObfuscationIn case all this didn’t make the network manager’s job hard enough…we renamed bridges to switcheswe renamed routers to switcheswe now have “multilayer switches” and “layerless switches”
13Entropy or Evolution?looks like the normal entropy (decay) that besets all large, engineered systems over timedon’t know where/how to reapply energy to fight the entropyless worrisome to view as evolution insteadthe Internet as an evolving lifeform or ecosystem?just let nature (the market) take its coursethough result is undesigned and unpredictable, should not be viewed as decay
14Survival of the Fittest? WWW phone...SMTP HTTP RTP...TCP UDP…IP6copper fiber radio...may evolve from an hourglass to a wineglassearly signs: IP-over-SONET, IP-over-WDMneed IPv6 to restore slim waist