LACP Meets OpenFlow Seamless Link Aggregation to OpenFlow Networks

Transcription

1 LACP Meets OpenFlow Seamless Link Aggregation to OpenFlow Networks Michael Bredel joint work with Markus Steinbacher

2 From CERN to Kufstein Kufstein, Austria CERN

3 University of Applied Sciences, Kufstein Tirol Founded 1997 Today, approx students bachelors and masters Approx. 100 Employees and 200 external lecturers Approx. 150 international partner universities Characteristics Small classes with a focus on team work in small groups Applied sciences and a focus on practical experiences

4 Outline Points of failure and how to avoid them Link aggregation at its glance Pros and cons of stacked switches Challenges of using an SDN approach for link aggregation Link discovery and multipath forwarding Host discovery using ARP messages and MAC addresses Any kind of error handling The link aggregation implementation based on Floodlight Advantages of using SDN for link aggregation

5 Points of failure and how to avoid them Connecting a server to the network state of the art Given a layer-2 network and a server Adding a second link for redundancy NIC link switch layer-2 switch

6 Points of failure and how to avoid them Connecting a server to the network state of the art Given a layer-2 network and a server Adding a second link for redundancy Adding a second switch for redundancy stacked switch

7 Stackable switches pros and cons Compared to the use of multiple standalone switches, stacking technology provides several advantages related to simplicity, scalability, and flexibility Virtual chassis capability Mixed media Each additional switch adds complexity with management, power demands, and performance. This is especially true when a stack grows beyond four switches Management difficulties Power demands Performance Inflexible

8 Challenges of using SDN for link aggregation Reactive SDN Configuration Management Automatic link discovery using LLDP Ability of performing link-layer multipath forwarding Automatic device discovery based on incoming packets Often using ARP messages and MAC addresses Error handling Flow reconciliation in case of port-down events Correctly detect node movements and cope with false node detection Detect and handle configuration errors

9 Floodlight OpenFlow SDN Controller Written in Java Easy-to-use At least compared to ODL Offers a module loading system that make it simple to extend and enhance Build-in support for various SDN applications Server Load Balancer Stateless Firewall

10 Floodlight OpenFlow SDN Controller Enhanced architecture

11 LAG configuration JSON configuration file: "pathfinder" : { "selector" : "roundrobin", "calculator" : "dijkstra" }, "linkaggregator" : { "LAG2" : { "ports" : { "00:00:00:00:00:00:00:01" : [ 1(0) ], "00:00:00:00:00:00:00:01" : [ 1(0) ] }, "mode" : { "selector" : "roundrobin" } }, "MY_arbitrary_LAG_Name" : { "ports" : { "00:00:00:00:00:00:00:03" : [ 1(0), 2(0) ] } } }

12 Advantages achieved by using SDN Aggregated links can connect to any switch-port at the SDN Within the network, the traffic flows can be optimized

13 LACP meets SDN Link Aggregation Control Protocol (LACP) Offers dynamic link aggregation IEEE 802.1AX-2008 (previously IEEE 802.3ad) Provides a method to control the bundling of several physical ports together to form a single logical channel LACP allows a network device to negotiate an automatic bundling of links by sending LACP packets to the peer With LACP implemented as a client on the SDN controller one does not need to configure anything on the SDN Link aggregation is done automatically based on the host configuration

14 Summary Introduced the university of applied sciences Kufstein Tirol Set the scene background on link aggregation Pros and cons of stacked switches and link aggregation Explained challenges of using SDN for link aggregation Automatic device discovery based on incoming packets Handling errors and other network events Explained our implementation that is based on the Floodlight OpenFlow SDN controller Showed the advantages of an SDN solution Flexibility Easy to use

15 Contact If you are interested in any kind of collaboration, don't hesitate to contact me Prof. (FH) Dr. Michael Bredel FH Kufstein Tirol Bildungs GmbH University of Applied Sciences Andreas Hofer-Straße 7, A-6330 Kufstein