Advanced Computer Networks

Network automation

Centralized control over distributed routing: fibbing

Fibbing: lying to routing protocols

• high-level language to specify forwarding requirements

  ((E, C, D1) and (E, G, D1);             // traffic between E and D1 load balanced on two paths
   ((A, *, B, * D2) or (A, *, C, *, D2)); // traffic between A and D2 should cross B or C
   (F, G, *, D3) as backupof ((F, H));)   // traffic between F and D3 should be reroutd via G if link (F,H) fails
  

• fibbing controller computes paths and creates fake topology by sending link-state messages

Synthesizing network configurations - Propane

Compile network-wide routing objectives into low-level configurations.

Main goals of Propane:

• language for expressing network-wide objectives (intra- and inter-domain routing)
• compiler for purely distribute implementation
  • generate BGP configs for each router
  • compiler guarantees policy compliance for all failures

Autocompleting partial network configurations

Problems:

• produced configs may widely differ from human-generating ones, lowering confidence in them
• can produce widely different configurations given slightly different requirements
• can’t flexibly adapt to operational requirements

Existing synthesizers don’t provide operators with fine-grained control over synthesized configurations.

NetComplete: network operators can specify their intents through configuration sketches with “holes”

• holes can identify specific attributes (e.g. IP addresses), link costs, BGP local preferences, or entire pieces of configuration
• encodes requirements as logical formula in SMT
• use solver (Z3) to find assignment that satisfies constraints