1. Wresting Control from BGP: Scalable Fine-grained Route Control
Patrick Verkaik, Dan Pei, Tom Scholl, Aman Shaikh , Alex C. Snoeren, Kobus van der Merwe
UCSD / AT&T Labs
contact:
Motivation:BGP causes load imbalance
We propose: route control using IRSCP
(Intelligent Route Service Control Point)
Typical BGP routing solution, hot-potato routing:
Limitations of BGP
BGP option 1: routers select single ISP-wide egress router
Rest of the Internet
Routers
2. IRSCP receives all egress routes from nearby customers and IRSCPs
1. Route control application measures the network and sends egress lists to IRSCP that avoid load imbalances
Routes for customer
ISP
ISP
Traffic to customer 4. #1 #2
Egress list for these three routers
IRSCP
IRSCP 4. 1.
congestion!
App
Egress routes C 2.
Routers pick nearest egress route
Leads to load imbalance for C
Potentially yielding congestion
IRSCP 4. 4.
Customer C 2.
Achieves this routing solution
BGP protocol controls ISP’s routing:
BGP advertises C to routers
Each router runs BGP decision process to select route to C
Traffic follows reverse path along selected routes
Below routing solution fixes the problem but unachievable in BGP
Egress list contains egress routes ordered by preference
3. IRSCP runs decision process: for each router, IRSCP decision process picks most preferred (according to egress list) available egress route
ISP C
4. IRSCP Informs nearby routers of its decision
Achieved output rate
Estimated max required input rate
Performance of prototype IRSCP
Connect to 40 emulated IRSCPs and 255 emulated (customer and ISP) routers
Vary number of ISP routers and plot maximum sustained throughput
Due to per-ISP-router decision process, more ISP routers means less throughput
IRSCP easily keeps up with estimated required 95-percentile input rate
To do: overcome bursts of maximum required input rate using flow control
Achieved input rate
Estimated 95 perc. required input rate
ISP
IRSCP
App
App
IRSCP
Network
measurement
BGP protocol
Lists of egress routes