アプリケーション 動的制御 ネットワークインフラ [1] D. Kreutz, et al., “Software-Defined Networking: A Comprehensive Survey,” Proc. of the IEEE, vol. 103, no. 1, pp. 14–76, Jan. 2015. [2] N. Feamster, et al., “The Road to SDN,” ACM Queue, vol. 11, issue 12, pages 20, Dec. 2013. [3] M.F. Bari, et al., “Data Center Network Virtualization: A Survey,” IEEE Comm. Surveys & Tutorials, vol. 15, no. 2, pp. 909–928, Q2, 2013. 3
を分離 • 制御機構を集約 4 Control Plane Data Plane Data Plane Data Plane Control Plane Control Plane Data Plane Data Plane Switch Switch Switch Controller ैདྷͷωοτϫʔΫ SDN ωοτϫʔΫ Control Channel Control Plane ・トポロジ収集 ・ルーティングテーブル生成など Data Plane ・パケット転送 (੍ޚνϟωϧ)
切断時に フローエントリ編集し 制御チャネルを確立 CCMM(Func=onality(1( S( M S( M He’s(alive CCMM(Func=onality(2( S( M S( M CCMM(Func=onality(3( S( M S( M S( M ✗( ✗( ✓( C( Control(Channel( via(new(path 9 (3) (2) (1)
3 C 1 2 3 C 1 2 3 C 1 2 3 C 1 2 3 (a) Out-to-in (b) In-to-in (c) In-to-in-middle Figure 5.3: Three failure cases in single specified link failure experiments chronously collects the network topology map, calculates the path, and installs the fl entries. This is considered to happen due to the reason that the in-to-in and the in-to middle case take a longer path than the other cases after the disconnection. After all switch alongside the path from the switch to the controller are configured, the switc can restore the connectivity to the controller. This describes the time between the tim C 1 2 3 C 1 2 3 C 1 2 3 C 1 2 3 C 1 2 3 C 1 2 3 (a) Out-to-in (b) In-to-in (c) In-to-in-middle Figure 5.3: Three failure cases in single specified link failure experiments chronously collects the network topology map, calculates the path, and installs the fl entries. This is considered to happen due to the reason that the in-to-in and the in-to middle case take a longer path than the other cases after the disconnection. After all switch alongside the path from the switch to the controller are configured, the switc 直接→間接 間接→間接 間接→間接(途中経路) 2 hops 2 hops 3 hops 3 nodes 4 nodes 4 nodes 211.5 ± 0.3 [ms] 246.3 ± 7.0 [ms] 211.5 ± 0.6 [ms] 279.3 ± 23.9 [ms] 217.9 ± 8.7 [ms] 292.7 ± 9.3 [ms] トポロジ生成時間 制御リンク復旧時間 ホップ数(切断後) ノード数 切断後 切断前 14
補足: ・帯域は1Gbps・遅延は地理的距離から算出設定 ・リンク切断は全て同時刻に行う ・リンク数N、リンク断率xの時、[x * N]リンクを断線させる。[…]は床関数。 ・復旧可能なスイッチ := 切断後にもコントローラへの接続経路を有するスイッチ ・ネットワーク復旧時刻 := 全復旧可能スイッチの制御リンク復旧時刻 実験・評価 › シナリオ2 [11] S. Knight, H. Nguyen, N. Falkner, R. Bowden and M. Roughan, “The Internet Topology Zoo,” IEEE Journal on Selected Areas in Communications, vol. 29, no. 9, pp. 1765–1775, Oct. 2011. [12] The University of Adelaide, “The Internet Topology Zoo,” http://www. topology-zoo.org/, last accessed at 21 Oct. 2014. 引用元: Topology Zoo [12] 17
Plane Data Plane Control Plane Control Plane Data Plane Data Plane Applica?ons Switch Switch Switch Switch Switch Controller Conven?onal Architecture SDN Architecture Control Channel Northbound API Southbound API 23
Switch [6] S. Sharma, et al., “Openflow: meeting carrier-grade recovery requirements,” Computer Communications, 2012. [7] N. L. M. van Adrichem, et al., “Fast recovery in software-defined networks,” IEEE EWSDN, 2014. [8] A. Sgambelluri, et al., “Openflow-based segment protection in ethernet networks,” IEEE/OSA JOCN, 2013.
Ports Interfaces Seen by applications With Open vSwitch Situa?on OSPF daemon Physical Ports Interfaces Seen by applications Bridge (Open vSwitch Bridge) OSPF daemon cannnot handle each ports separately 42
OSPF daemon Physical Ports Interfaces Bridge ・Create the same number of Internal Ports With Open vSwitch Situation (Fixed) (2) OSPF daemon Physical Ports Interfaces ・Insert OSPF-passthrough flow entries 43
00 01 02 03 04 05 06 07 08 09 10 11 12 13 Time from link down [s] 0 5 10 15 20 25 30 35 # of restored switches 0.0 0.2 0.4 0.6 0.8 1.0 Ratio of restored switches to total switches 52
are Disconnected Reachable domain Controller Switch S C C S S S S S S S C S S S S S S ✗ ✗ Unreachable domain Unreachable domain ANer Links are Disconnected