Network Research An Operator’s Perspective Terry Gray University of Washington Associate Vice President, Technology Engineering, C&C Affiliate Professor, CS&E

Theme  "Every day's a winding road" -S. Crow  "Every day's a research experiment" -T. Gray

Questions  Seen any 404s go away by themselves lately?  Is the trend getting better or worse?  What is the max retry count in MS Windows?  TcpMaxDataRetransmissions = ?  Could there be a connection?

Thesis  The (open) Internet died in 2003 at the hands of slammer and blaster  It's no longer about pervasive connectivity… now it’s all about (selective) isolation  Tolerance for, and frequency of, glitches.. is increasing  Current Internet model is busted… e.g. silent failures, poor diagnostics

Buzz Words  trust-mediated  convergence/virtualization

Miscellany  Perimeter Protection Paradox  Good ol' days of the network utility model  Defense-in-Depth vs MTTD, etc Claim:  M-T-to-penetration, innovation, diagnosis ~ d**2  How many arbitrary PEPs before the overall system becomes non-deterministic?

Trends  Software-defined networks  Personal lambdas  Port 80/443 tunneling to get thru firewalls  Encryption  End-point firewalls (changes diagnostic picture)  More policy boundaries; less effective  Regulation/compliance

Imagine  Being in a NOC with an irate customer on the phone:  Customer: "Is the network broken?"  NOC: "I give up, is it?“

Hard problems  DDOS  Worsening MTTG  Diagnosis complexity (MTTD)  Provisioning complexity (vs. network utility)  Mismatch between best and common deployment e.g. tcp retry count, duplex mismatch, stack-tuning  S/N ratio of behavioral IDS monitors  Path policy discovery  Trust management  Policy enforcement is silent; looks like net failure

Hard problems (cont’d)  Managing heterogenity: bugs, conventions (jumbos)  Organizational vs. geographic topologies  Scaling personal lambdas  Managing/diagnosing with e2e encryption  Exception management  Seduction of more protocols (e.g. MTR)  Attribution vs. anonymity  Multicast fault containment  Optimal fault-zone sizing

Conclusions  Plenty of work to do  Help needed now!  Current problems must inform future/clean-slate proposals