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IEEE CCW ‘08
New Network Architectures:Why Bother?
Paul FrancisCornell
What is a “home run” in systems research?
Huge impact on industry
Intellectually compelling idea
Something that industry wouldn’t have done on its own
Impact
Intellectual
Not done byIndustry
A home run
What is a “home run” in systems research?
Huge impact on industry
Intellectually compelling idea
Something that industry wouldn’t have done on its own
As industry matures, these get increasingly difficult
Impact
Intellectual
Not done byIndustry
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 possibleInter-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
Don’t 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
Dest Next Hop20.5/16 1.1.1.136.3/16 2.1.1.1. . . .
Virtual Aggregation: FIBs have routes to only part of the address space
Virtual Prefixes
Dest Next Hop20.5/16 1.1.1.1. . . .
Dest Next Hop188.3/16 2.1.1.1. . . .
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”, what’s 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
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