200 likes | 326 Views
Peer Policy Policing with. NETFLOW. NANOG 25 June 9, 2002. Matthew Meyer. Traffic Engineering. NANOG 25 June 9, 2002. The Global Crossing Network. 200 + On Net Cities 27 On Net Countries Nearly 100,000 route miles 17 Metro Networks. Peer Policy Policing With Netflow.
E N D
Peer Policy Policing with NETFLOW NANOG 25 June 9, 2002
Matthew Meyer Traffic Engineering NANOG 25 June 9, 2002
The Global Crossing Network • 200 + On Net Cities • 27 On Net Countries • Nearly 100,000 route miles • 17 Metro Networks
Peer Policy Policing With Netflow • Discovering and engaging the wayward packet flows that stumble onto your network • Giving default free networking a fighting chance • Get off my lawn • Bottom line: Just detecting a peer defaulting traffic us
Peer Policy Policing with Netflow Defining the problem • Telecom & Internet-space companies going into Ch11 • Punctuated mass customer moves due to Ch7 backbone liquidations • Peering less flexible • Some will resort to uncouth methods to mitigate the congestion and sidestep potential costs
Peer Policy Policing with Netflow Defining the problem • Fewer players, larger peerings • Peering inherits more flux and less flexibility to deal with it • Some more liberal peering channels may dry up or become heavily utilized
Peer Policy Policing with Netflow Addressing the Problem • Time to think like a bean counter • Is peering being abused? • Effect: Lower capex due to longer upgrade cycles • End goal: Knowing that we run a tight ship and being alerted when uninvited traffic enters the network
Peer Policy Policing with Netflow Measurement • Not rocket science • 1:100 Netflow sampling • Sampling points: All traffic arriving on our border routers • Currently set to do peer-as type flow export
Peer Policy Policing with Netflow Measurement • One centrally located collector • Collector handling approximately 20 selected routers • Collector iBGP peers with border routers • Records route table changes every 5 minutes • Dual Pentium III, 1G memory, multiple Ultra-160 SCSI drives, directly connected to backbone
Peer Policy Policing with Netflow Measurement DEFAULTING PEER REPORT: Rec'd Peer Bytes percentage of total router interface destined for peer Bytes for interface br2.HUB1.gblx.net_so-2/1/3.0 0.011M 0.006 <-Peer A br2.HUB1.gblx.net_so-2/1/0.0 0.026M 0.008 <-Peer B br2.HUB1.gblx.net_so-3/1/0.0 0.087M 0.008 <-Peer C br2.HUB1.gblx.net_so-2/1/2.0 0.145M 0.011 <-Peer D br2.HUB1.gblx.net_at-2/2/0.0 0.167M 0.024 <-Peer E br2.HUB1.gblx.net_so-1/2/3.0 0.339M 0.017 <-Peer F br2.HUB1.gblx.net_so-3/1/2.0 2.464M 0.246 <-Peer G br2.HUB1.gblx.net_so-0/0/0.0 3319.615M 56.722 <-uplink br2.HUB1.gblx.net_so-1/0/0.0 3381.523M 61.515 <-uplink
Measurement Peer Policy Policing with Netflow EXAMPLE OF FLOWDATA /Ixia/SeeFlow/bin/rseeas2as -S '20020603 00:00' br2.w00t1.gblx.net Facets: TimeInterval : 06/04/2002 16:50:49.217018 - 06/04/2002 19:31:52.879363 UTC RouterIpv4Addr : 10.10.10.10 InputIfIndex : 67 InputIfIpv4Addr : 10.0.0.1 InputIfName : so-1/2/3.0 RouterName : br2.w00t1.gblx.net Src AS Dst AS Packets Pkts/sec Bytes Bits/sec ------- ------- ------------- ------------- ------------- ------------- 1111 2222 654.061K 67.683 321.386M 266.058K 1111 3333 177.794K 18.398 130.125M 107.723K 99 44444 139.861K 14.473 91.889M 76.070K 1111 3549 257.006K 26.595 78.603M 65.071K 1111 5555 72.634K 7.516 65.807M 54.478K [~300 more lines clipped]
Peer Policy Policing with Netflow Manipulating the Data • Extracted with Ixia tools • 24 hour cumulative byte count per interface + dest-as key pair • Created a peer-as list • Ignored incorrectly reported Netflow data according to routing policy
Peer Policy Policing with Netflow Where to Look • Our design is hierarchical • Peers tend to be on dedicated peering routers • Our peering in consistent and rich • Collecting closer to the core would not catch this behavior universally
Peer Policy Policing with Netflow Analysis • BGP import policy gets in the way of trusting source AS • Trace levels of false peer to peer traffic associated with most peering interfaces • In initial beta, no peers have been found blatantly defaulting to us
Peer Policy Policing with Netflow So Far So Good • For the moment peer defaulting does not seem to be a problem • We can move forward and easily complete a detection system • Feeling more confident about possible tighter peering ahead
Peer Policy Policing with Netflow What’s Next • Change flow export style from peer-as to origin-as • Putting the discovery ‘on cron’ • Long term: • Distribute collection • Build some visualization • Integrate with RRDtool
Peer Policy Policing with Netflow Retrospect • Good exercise in ‘Netflow 101’ • Sampling capability excellent • Data quality excellent • Restored confidence in Netflow reliability
SEAMLESS NETWORK. GLOBAL REACH.