Greening Backbone Networks

Greening Backbone Networks

30-minute presentation for the Green IT and Smart Grid course at Stony Brook University, on "Greening Backbone Networks" by Fisher et. al published at the first SIGCOMM green networking workshop in 2010.

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Emaad Manzoor

March 07, 2016
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Transcript

  1. 1.

    Greening Backbone Networks Emaad Ahmed Manzoor CSE691: Green IT &

    Smart Grid March 2016 Will Fisher, Martin Suchara, Jennifer Rexford First Workshop on Green Networking, SIGCOMM ’10
  2. 18.
  3. 19.

    G(V, E) s t w u v c(u,t) c(w,v) c(v,t)

    c(s,w) c(s,u) Topology Input
  4. 20.

    G(V, E) s t w u v c(u,t) c(w,v) c(v,t)

    c(s,w) c(s,u) Topology D (s1, t1, h2) (s2, t2, h2) . . . Demands Input
  5. 21.

    G(V, E) s t w u v c(u,t) c(w,v) c(v,t)

    c(s,w) c(s,u) Topology D (s1, t1, h2) (s2, t2, h2) . . . Demands Cables per link B Input
  6. 22.
  7. 23.

    s t w u v c(u,t) c(w,v) c(v,t) c(s,w) c(s,u)

    Flow of demand d on each link fd(s,u) fd(s,w) fd(w,v) fd(v,t) fd(u,t) fd(u, v) Output
  8. 24.

    s t w u v c(u,t) c(w,v) c(v,t) c(s,w) c(s,u)

    Flow of demand d on each link fd(s,u) fd(s,w) fd(w,v) fd(v,t) fd(u,t) Total flow on link (u,v) f(u, v) = X d fd(u, v) fd(u, v) Output
  9. 26.

    min number of powered cables s.t. link loads ≤ capacities

    flow conservation carries all traffic demands
  10. 28.

    min s.t. flow conservation carries all traffic demands X (u,v)2E

    f(u, v) X D fd(u, v)  c(u, v), 8(u, v) 2 E
  11. 29.

    min s.t. carries all traffic demands X (u,v)2E f(u, v)

    X D fd(u, v)  c(u, v), 8(u, v) 2 E X v2V fd(u, v) = X w2V fd(w, u), 8d, 8u 6= sd, td
  12. 30.

    min s.t. X (u,v)2E f(u, v) X D fd(u, v)

     c(u, v), 8(u, v) 2 E X v2V fd(sd, v) = X w2V fd(w, td) = hd, 8d X v2V fd(u, v) = X w2V fd(w, u), 8d, 8u 6= sd, td
  13. 31.

    min number of powered cables s.t. link loads ≤ capacities

    flow conservation carries all traffic demands Models what if links are energy proportional? • Fractional linear program • Bounds on power savings
  14. 32.

    Upper bound on energy savings f(u,v) = 6.3 Gbps (solution

    of FLP) c(u,v) = 10 Gbps (given topology) B = 10 (given cables per link) — Round down: 6 Gbps — Turn off: 4 cables
  15. 33.

    Lower bound on energy savings f(u,v) = 6.3 Gbps (solution

    of FLP) c(u,v) = 10 Gbps (given topology) B = 10 (given cables per link) — Round up: 7 Gbps — Turn off: 3 cables
  16. 38.

    min X (u,v)2E nuv Minimise the sum of the number

    of active cables on each link f(u, v)  nuv B c(u, v), 8(u, v) 2 E Number of active cables need to be sufficient for the demand
  17. 39.

    min X (u,v)2E nuv Minimise the sum of the number

    of active cables on each link f(u, v)  nuv B c(u, v), 8(u, v) 2 E Number of active cables need to be sufficient for the demand NP-Complete — D2CIF
  18. 41.

    Fast Greedy Heuristic 1. Solve FLP - Obtain f(u,v), round

    up. 2. Find (u,v) with the most unused capacity - Remove one cable from the link. - Solve the FLP with the new capacities. Feasible? Remove a cable from the link (u,v).
  19. 42.

    Fast Greedy Heuristic 1. Solve FLP - Obtain f(u,v), round

    up. 2. Find (u,v) with the most unused capacity - Remove one cable from the link. - Solve the FLP with the new capacities. Feasible? Remove a cable from the link (u,v). Not feasible? Mark link (u,v) as final.
  20. 43.

    Fast Greedy Heuristic 1. Solve FLP - Obtain f(u,v), round

    up. 2. Find (u,v) with the most unused capacity - Remove one cable from the link. - Solve the FLP with the new capacities. Feasible? Remove a cable from the link (u,v). Not feasible? Mark link (u,v) as final. Repeat from 2, ignoring all final links
  21. 44.

    Exhaustive Greedy Heuristic Remove the cable that - Retains solution

    feasibility. - Minimises the marginal penalty of each removal. Marginal penalty - Increases as excess traffic is rerouted along longer paths. - Measures as the FLP objective difference after cable removal.
  22. 49.
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  26. 57.

    .