IEEE CCW 08 New Network Architectures: Why Bother? Paul Francis Cornell

What is a home run in systems research? Huge impact on industry Intellectually compelling idea Something that industry wouldnt have done on its own

Impact Intellectual Not done by Industry A home run

What is a home run in systems research? Huge impact on industry Intellectually compelling idea Something that industry wouldnt have done on its own As industry matures, these get increasingly difficult

Impact Intellectual Not done by Industry This is new architecture (clean slate) research

Dirty slate research.... Maybe. But only with incrementally deployable ideas. Is it possible to hit a home run in networking research these days? Finding a fun project that industry wants to deploy is itself an intellectual challenge....

One approach is to become a vendor The challenge of impact in network research: Need buy-in from providers, vendors, and standards Do a startup But this is not always possible Inter-domain routing, for instance

One Bottleneck at a Time Rather, solve the current most serious problem, move on Our approach to inter-domain routing research Dont solve every problem at once

Virtual Aggregation (ViAggre) In fact, ViAggre requires no changes to router software! ISPs sometimes have to replace hardware because of FIB growth Shrinks the BGP FIB (by easily 10x), but leaves the RIB intact Intact RIB means no real change to how routing is done

Today: All router FIBs have routes to all destinations DestNext Hop 20.5/ /

Virtual Aggregation: FIBs have routes to only part of the address space Virtual Prefixes DestNext Hop 20.5/ Dest Next Hop 188.3/

Paths through the ISP have two components: 1: Route to a nearby Aggregation Point 2: Tunnel to the neighbor router

1: Routing to a nearby Aggregation Point Configure Aggregation Point with static route for the Virtual Prefix Virtual Prefix is advertised into BGP

2: Tunnel packet to neighbor router (MPLS) Static routes for all neighbors are imported into OSPF MPLS LDP creates tunnels to every neighbor router

Turns out, providers are nervous about doing anything without vendor blessing We thought we could bypass vendors and standards Providers could deploy this on their own Fortunately, a vendor (Huawei) became interested in this

Huawei is implementing it Standardizing ViAggre in IETF (IDR) Going well, because no changes to BGP With RFC in hand, can try to get providers to convince other vendors to implement

I suspect that it is not RIB size, but rather BGP update processing cost Assuming FIB is solved, whats the next bottleneck? We are starting some router measurements to find out Can we reduce the cost of updates while running BGP more-or-less as is?

Mapped-BGP Filtering, best-path selection, load- balance, aggregation, route policies Expense of route processing are all the policies Our goal is to get rid of the policies for most prefixes

Rather than distribute routes to all prefixes, distribute routes to tunnel endpoints, and distribute maps that bind prefixes to tunnel endpoints Make the maps policy-free Exploit tunnels to improve inter-AS load balance and increase aggregation opportunities