Software-Defined Networking an der Universität Münster

Transcription

1 Software-Defined Networking an der Universität Münster Tim Humernbrum Institut für Informatik Arbeitsgruppe Prof. Gorlatch Kolloquium Erneuerung des Kommunikationssystems der WWU, 4. November 2016

2 1. Quality of Service with SDN

3 Problems with QoS in Traditional Networks Network components (routers, switches) are closed systems Control logic managing the forwarding of data packets is integrated in the components Only limited possibilities for influencing packet forwarding decisions No possibilities to dynamically react to problems like congestion of specific routes Current Quality of Service (QoS) standards (e. g. IntServ, DiffServ) are static and not widely supported Nearly all applications use the network on a best-effort basis 1

4 Exploiting SDN for Improving QoS With Software-Defined Networking (SDN), applications can dynamically reconfigure the network for their purposes Our goal: Provide QoS for real-time applications using SDN Our work: Novel API and its implementation for QoS specification and monitoring Central research challenge: Translation: application QoE network QoS Controller adapts network to fulfil QoS Server sends network SDN QoS requirements Controller to SDN Controller QoS QoS API Game Client SDN Network Game Server 2

5 QoS API Basic Architecture QoS requirements are specified by the developer for a particular flow using the application-level API ➀ The QoS requirements are automatically reported to the SDN controller by the SDN Module via the network-level API ➁ Application Layer Control Layer ROIA Game Client Client Game Client... Actions 2 SDN Controller Game Server 1 Application Code SDN Module RTF State Update Network Layer Network 3

6 Application-Level Metrics Problem: the SDN controller can only understand and manage QoS requirements which are based on network-level metrics, e. g., throughput, packet loss, etc. These are too low-level from the developers point of view and not directly related to application-level metrics SDN Module provides application-level metrics for the specification of QoS requirements to the developer, e. g., response time Automatic translation into network-level metrics at runtime Design goal: transparent for the developer, no different usage of application- and network-level metrics in the SDN Module 4

7 Basic Translation Concept Application Code d a applicationlevel QoS QoS Requirement Specification To SDN Controller networklevel QoS c Translation SDN Module b Runtime Application Monitoring RTF Once an application-level requirement has been specified, steps b) d) are continuously repeated and the translated QoS requirement is adapted if the runtime monitoring data changes 5

8 2. Multicast with SDN

9 Multicast (MC) Traditional networks: IP multicast, key properties: Receiver initiated: receivers subscribe at local MC router (IGMPv3/MLDv2) No membership control possible for the sender Every host can send to any MC group without joining it Distributed MC routing (e. g., using PIM) Not desirable in many application use-cases Receiver IGMP LAN L2 Switch (IGMP Snooping) UDP Management Traffic Local MC Router PIM WAN MC Router Multicast Traffic Sender 6

10 Multicast (MC) Our approach: multicast exploiting the centralized SDN architecture Sender initiated: no action required from the receivers Full membership control for the initiator Only the initiator is able to send data to the MC group Centralized MC routing by the SDN controller Alternative to IP multicast, not a replacement 7

11 SDN-based Multicast: Example Scenario Host Host Host 1 (sender) Port 1 Port 2 Switch B Switch A Example scenario: host 1 sends data to hosts 2 and 3 using multicast The multicast is initialized in 4 steps 8

12 SDN-based Multicast: Step 1 Multicast Group Host Host Host 1 (sender) Port 1 Port 2 Switch B Switch A Step1: host 1 specifies a multicast group with IP adresses of 2 and 3 8

13 SDN-based Multicast: Step 2 Multicast Group Host Host Host 1 (sender) Switch B Port 1 Port 2 Switch A SDN Controller Step 2: the group specification is sent to the SDN controller 8

14 SDN-based Multicast: Step 3 Multicast Group Host Host Host 1 (sender) IP src IP dst action modify header IP dst = out port 2 modify header IP dst = out port Switch B IP src Port 1 IP dst Port 2 Switch A action out port 1 SDN Controller Step 3: the SDN controller installs the multicast in the network New rules are added to the flow tables of switches A and B 8

15 SDN-based Multicast: Step 4 Multicast Group Host Host Host 1 (sender) IP src IP dst action modify header IP dst = out port 2 modify header IP dst = out port Switch B IP src Port 1 IP dst Port 2 Switch A action out port SDN Controller Step 4: the multicast address is returned by the SDN controller to host 1 8

16 SDN-based Multicast: Sending Data Multicast Group Host Host Host 1 (sender) IP src IP dst action modify header IP dst = out port 2 modify header IP dst = out port Switch B IP src Port 1 IP dst Port 2 Switch A action out port 1 Host 1 sends a multicast packet to the multicast address (d = ) 8

17 SDN-based Multicast: Sending Data Multicast Group Host Host Host 1 (sender) IP src IP dst action modify header IP dst = out port 2 modify header IP dst = out port Switch B IP src Port 1 IP dst Port 2 Switch A action out port 1 Host 1 sends a multicast packet to the multicast address (d = ) 8

18 SDN-based Multicast: Sending Data Multicast Group Host Host Host 1 (sender) IP src IP dst action modify header IP dst = out port 2 modify header IP dst = out port Switch B IP src Port 1 IP dst Port 2 Switch A action out port 1 The packet matches the new rule in switch A and is forwarded to B 8

19 SDN-based Multicast: Sending Data Multicast Group Host Host Host 1 (sender) IP src IP dst action modify header IP dst = out port 2 modify header IP dst = out port Switch B IP src Port 1 IP dst Port 2 Switch A action out port 1 The packet matches the new rule in switch A and is forwarded to B 8

20 SDN-based Multicast: Sending Data Multicast Group Host Host Host 1 (sender) IP src IP dst action modify header IP dst = out port 2 modify header IP dst = out port Switch B IP src Port 1 IP dst Port 2 Switch A action out port 1 In switch B, the multicast paket is transformed into a unicast paket: the multicast address d is replaced by the unicast address d + of host 2 8

21 SDN-based Multicast: Sending Data Multicast Group Host Host Host 1 (sender) IP src IP dst action modify header IP dst = out port 2 modify header IP dst = out port Switch B IP src Port 1 IP dst Port 2 Switch A action out port 1 In switch B, the multicast paket is transformed into a unicast paket: the multicast address d is replaced by the unicast address d* of host 3 8

22 SDN-based Multicast: Sending Data Multicast Group Host Host Host 1 (sender) IP src IP dst action modify header IP dst = out port 2 modify header IP dst = out port Switch B IP src Port 1 IP dst Port 2 Switch A action out port 1 The modified packets are forwarded to hosts 2 and 3, respectively 8

23 SDN-based Multicast: Sending Data Multicast Group Host Host Host 1 (sender) IP src IP dst action modify header IP dst = out port 2 modify header IP dst = out port Switch B IP src Port 1 IP dst Port 2 Switch A action out port 1 The modified packets are forwarded to hosts 2 and 3, respectively 8

24 Advantages of SDN-based Multicast Sender initiated Sender specifies the MC group and initiates the MC Receivers can be added and removed dynamically Minimized management overhead in the network: no IGMP needed Receiver transparent MC packets are transformed into unicast packets before their delivery Minimized frame filtering in receivers NIC and IP stack Receivers cannot send to MC group without sender Also works with IPv6 (requires OpenFlow 1.2 support) 9

25 Multicast Trees Potential problem of SDN-based MC (also of IP MC): MC forwarding rules are stored in the switches Flow table size is a potential bottleneck for MC scalability limited number and/or size of MC groups Central research challenges: Reduce the number of switches for realizing MC Save flow table space by reusing unicast entries 10

26 Multicast Trees s2 receiver h3 sender h1 s1 receiver h2 s4 h4 s3 s6 h5 h6 s7 s5 s8 receiver h7 Traditional MC routing: find a path to all receivers of a MC group by using Shortest-Path Trees (SPT) 11

27 Multicast Trees s2 receiver h3 sender h1 s1 receiver h2 s4 h4 s3 s6 h5 h6 s7 s5 s8 receiver h7 Traditional MC routing: find a path to all receivers of a MC group by using Shortest-Path Trees (SPT) 11

28 Multicast Trees s2 receiver h3 sender h1 s1 receiver h2 s4 h4 s3 s6 h5 h6 s7 s5 s8 receiver h7 Applying our so-called Branch-aware Modification (BAM) to an SPT allows for reusing unicast entries 11

29 3. SDN-Pilotprojekt zur Netzsicherheit

30 Zugangsschutz zum LAN mit SDN Kooperation zwischen dem Institut für Informatik und dem ZIV Bachelorarbeit zum Thema Zugangsschutz mit SDN als Alternative zu IEEE 802.1X Motivation: Erfahrungsaufbau mit SDN Ziele des Projekts: Endgeräte anhand ihrer MAC-Adresse autorisieren Einfache, zentrale Konfiguration Gruppierung von Switches/Ports zu Zugangsbereichen Filtern bestimmter Diensten Keine zusätzliche Software für die Endgeräte Umsezung als Modul für den HPE VAN SDN Controller Fortsetzung des Projekts in Abschlussarbeiten und Seminaren 12

31 Konzept des Zugangsschutzes mit SDN SDN Controller configure access rules Edge Core Administrator 13

32 Konzept des Zugangsschutzes mit SDN SDN Controller Edge Core set rules normal switching 13

33 Konzept des Zugangsschutzes mit SDN Web Server Edge Core 13

34 Konfiguration der Zugangsschutz-App Web-Portal zur Konfiguration des Zugangsschutzes für den Administrator 14

35 Vielen Dank! 14