PCE - 68th IETF PCE Policy Architecture draft-ietf-pce-policy-enabled- path-comp-01.txt Igor Bryskin Dimitri Papadimitriou Lou Berger Jerry Ash

PCE - 68th IETF Changes from previous version No significant technical changes Editorial changes Re-added figures lost in merge with draft-berger-pce-policy-architecture-00.txt Some other minor edits Updated references, boilerplate, etc. Added co-author Biggest change: added scenario

PCE - 68th IETF Advanced Load Balancing Scenario IGP routing may direct all PE3/PE4/PE5 ingress traffic to egress PE2 Example in [IRSCP]: 71.8% of multi-homed traffic goes to one link (complete imbalance) PCE policies could be configured such that traffic load monitored (e.g., based on Netflow data) at ingress routers PE3  PE7 towards data center prefixes served by egress routers PE1 & PE2 PCE path computations balance traffic load, e.g., PE4/PE5 to egress PE1, thus overriding default IGP based selection PE1 PE7 PE5 PE2 PCE PE10 PE8 PE3 CE PE6 AS 1 Customer Network PE4 PE9 PCEP Physical link P3 P1 P2 AS 0

PCE - 68th IETF Advanced Load Balancing Scenario Good example of how PCE policy can account for info not advertised as TE link/node attributes such info cannot be included in explicit path computation constraints such info can be pretty much anything (e.g., traffic demand forecasts, flow monitoring feedback, any administrative policies, etc.) Further examples in [IRSCP] of how PCE policies might address certain network routing problems selective DDoS blackholing planned maintenance dryout VPN gateway selection.

PCE - 68th IETF Next Steps Additional feedback