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Active Networking and End-to-End Argument

Active Networking and End-to-End Argument. Samrat Bhattacharjee Kenneth L. Calvert Ellen W. Zegura. Objective. End-to-End Argument Active Networking – Extension of E2E argument End System approach Vs Combined System approach Performance Model to quantify the above approaches.

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Active Networking and End-to-End Argument

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  1. Active Networking and End-to-End Argument Samrat Bhattacharjee Kenneth L. Calvert Ellen W. Zegura

  2. Objective • End-to-End Argument • Active Networking – Extension of E2E argument • End System approach Vs Combined System approach • Performance Model to quantify the above approaches

  3. E2E and Active Networking • What is E2E? • Is Active Networking a natural consequence of E2E? • E2E and placement of functionality • All applications might not use the service • Trade-off between performance and cost • Combine network and application information to optimize performance

  4. Model for Service Location • Analyze performance under two design options – • Design X : Service implementation exclusive in the end-systems • Design C : Service achieved through combination of implementation at the end-system and in the network • Network is treated monolithically • Network support is boolean

  5. Model for Service Location • Parameters of performance model • Exclusively End-system (Design X) • Tx – Expected Performance • Combined End-system and Network (Design C) • Tc – Expected performance • Pn – Probability that the network support accomplishes the service • Te – Expected performance, end-system version • Tn – Expected performance, network version • Tc = (1-Pn) Te + Pn Tn

  6. Reliable Data Transfer • Performance Metric : Expected Transfer Time • Design X : • tx – time to request, receive and check the integrity • p – probability of error in each transmission • Tx – expected transfer time • Tx = i=1P(i transmissions) * i * tx = tx / (1-p)

  7. Reliable Data Transfer ... • Design C • tc – time to request, receive and check the integrity • p – probability of error in each transmission • q – probability that the network can correct the error • Pn Tn = (1 – p + pq) tc • Te = tc + i=1P(i transmissions) * i * tc = tc (1+1 / (1-p+pq) ) • Tc = (1 – p + pq) tc + p(1-q) * tc (1+1 / (1-p+pq) )

  8. Reliable Multicast • Performance metric : Latency (no of hops) • Design X • Buffering and Retransmission done only at the Receivers • Request message is directed to a “nearby” Receiver through the Loss node • Design C • Buffering and Retransmission done by the network nodes

  9. Reliable Multicast ...

  10. Reliable Multicast ... • Tx = tR+tL + tY + 2tR’ + tE + tR • TN = 2(tR+tL + 1) • TE = 2(tR+tL + tL’ + tS) • Tc = 2pn (tR+tL + 1) + 2 (1-pn) (tR+tL + tL’ + tS) • assume tR = tR’ = tS and tL = tL’ Tx = 4tR+tL + tY + tE Tc = 4tR+4tL - 2pn (tR+tL - 1) • If pn > (3tL-tE - tY ) / (2(tR+tL - 1)) then Tc < Tx ( combined system approach is better)

  11. Congestion Control • Application knows how to adapt • Network knows where and when to adapt • Flow packets contain advice about how to control congestion and may be stored at the network node

  12. Best Effort MPEG Delivery • Partial Packet Discard - discard packets on buffer overflow • Static Priority Discard - two level priority scheme • Frame Level Discard – queue a datagram iff its corresponding frame can be entirely queued • Group of Picture Level Discard – if I-frame is dropped, drop corresponding P & B frames.

  13. Performance Analysis • Performance metric : fraction of received data not discarded • Di,k – fraction of discarded data • Ti,k – performance of model i at a source rate of k Mbps • i = { P, S, F, G }

  14. Performance Analysis • Performance metric : signal-to-noise ratio

  15. Conclusion • Active networking is consistent with, and even suggested by the E2E argument • Active networks outperform the end-to-end solutions ?

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