== L2Switch User Guide === Overview The L2Switch project provides Layer2 switch functionality. === L2Switch Architecture * Packet Handler ** Decodes the packets coming to the controller and dispatches them appropriately * Loop Remover ** Removes loops in the network * Arp Handler ** Handles the decoded ARP packets * Address Tracker ** Learns the Addresses (MAC and IP) of entities in the network * Host Tracker ** Tracks the locations of hosts in the network * L2Switch Main ** Installs flows on each switch based on network traffic === Configuring L2Switch This sections below give details about the configuration settings for the components that can be configured. The base distribution configuration files are located in distribution/base/target/distributions-l2switch-base-0.1.0-SNAPSHOT-osgipackage/opendaylight/configuration/initial The karaf distribution configuration files are located in distribution/karaf/target/assembly/etc/opendaylight/karaf === Configuring Loop Remover * 52-loopremover.xml ** is-install-lldp-flow *** "true" means a flow that sends all LLDP packets to the controller will be installed on each switch *** "false" means this flow will not be installed ** lldp-flow-table-id *** The LLDP flow will be installed on the specified flow table of each switch *** This field is only relevant when "is-install-lldp-flow" is set to "true" ** lldp-flow-priority *** The LLDP flow will be installed with the specified priority *** This field is only relevant when "is-install-lldp-flow" is set to "true" ** lldp-flow-idle-timeout *** The LLDP flow will timeout (removed from the switch) if the flow doesn't forward a packet for _x_ seconds *** This field is only relevant when "is-install-lldp-flow" is set to "true" ** lldp-flow-hard-timeout *** The LLDP flow will timeout (removed from the switch) after _x_ seconds, regardless of how many packets it is forwarding *** This field is only relevant when "is-install-lldp-flow" is set to "true" ** graph-refresh-delay *** A graph of the network is maintained and gets updated as network elements go up/down (i.e. links go up/down and switches go up/down) *** After a network element going up/down, it waits _graph-refresh-delay_ seconds before recomputing the graph *** A higher value has the advantage of doing less graph updates, at the potential cost of losing some packets because the graph didn't update immediately. *** A lower value has the advantage of handling network topology changes quicker, at the cost of doing more computation. === Configuring Arp Handler * 54-arphandler.xml ** is-proactive-flood-mode *** "true" means that flood flows will be installed on each switch. With this flood flow, each switch will flood a packet that doesn't match any other flows. **** Advantage: Fewer packets are sent to the controller because those packets are flooded to the network. **** Disadvantage: A lot of network traffic is generated. *** "false" means the previously mentioned flood flows will not be installed. Instead an ARP flow will be installed on each switch that sends all ARP packets to the controller. **** Advantage: Less network traffic is generated. **** Disadvantage: The controller handles more packets (ARP requests & replies) and the ARP process takes longer than if there were flood flows. ** flood-flow-table-id *** The flood flow will be installed on the specified flow table of each switch *** This field is only relevant when "is-proactive-flood-mode" is set to "true" ** flood-flow-priority *** The flood flow will be installed with the specified priority *** This field is only relevant when "is-proactive-flood-mode" is set to "true" ** flood-flow-idle-timeout *** The flood flow will timeout (removed from the switch) if the flow doesn't forward a packet for _x_ seconds *** This field is only relevant when "is-proactive-flood-mode" is set to "true" ** flood-flow-hard-timeout *** The flood flow will timeout (removed from the switch) after _x_ seconds, regardless of how many packets it is forwarding *** This field is only relevant when "is-proactive-flood-mode" is set to "true" ** arp-flow-table-id *** The ARP flow will be installed on the specified flow table of each switch *** This field is only relevant when "is-proactive-flood-mode" is set to "false" ** arp-flow-priority *** The ARP flow will be installed with the specified priority *** This field is only relevant when "is-proactive-flood-mode" is set to "false" ** arp-flow-idle-timeout *** The ARP flow will timeout (removed from the switch) if the flow doesn't forward a packet for _x_ seconds *** This field is only relevant when "is-proactive-flood-mode" is set to "false" ** arp-flow-hard-timeout *** The ARP flow will timeout (removed from the switch) after _arp-flow-hard-timeout_ seconds, regardless of how many packets it is forwarding *** This field is only relevant when "is-proactive-flood-mode" is set to "false" === Configuring Address Tracker * 56-addresstracker.xml ** timestamp-update-interval *** A last-seen timestamp is associated with each address. This last-seen timestamp will only be updated after _timestamp-update-interval_ milliseconds. *** A higher value has the advantage of performing less writes to the database. *** A lower value has the advantage of knowing how fresh an address is. ** observe-addresses-from *** IP and MAC addresses can be observed/learned from ARP, IPv4, and IPv6 packets. Set which packets to make these observations from. === Configuring L2Switch Main * 58-l2switchmain.xml ** is-install-dropall-flow *** "true" means a drop-all flow will be installed on each switch, so the default action will be to drop a packet instead of sending it to the controller *** "false" means this flow will not be installed ** dropall-flow-table-id *** The dropall flow will be installed on the specified flow table of each switch *** This field is only relevant when "is-install-dropall-flow" is set to "true" ** dropall-flow-priority *** The dropall flow will be installed with the specified priority *** This field is only relevant when "is-install-dropall-flow" is set to "true" ** dropall-flow-idle-timeout *** The dropall flow will timeout (removed from the switch) if the flow doesn't forward a packet for _x_ seconds *** This field is only relevant when "is-install-dropall-flow" is set to "true" ** dropall-flow-hard-timeout *** The dropall flow will timeout (removed from the switch) after _x_ seconds, regardless of how many packets it is forwarding *** This field is only relevant when "is-install-dropall-flow" is set to "true" ** is-learning-only-mode *** "true" means that the L2Switch will only be learning addresses. No additional flows to optimize network traffic will be installed. *** "false" means that the L2Switch will react to network traffic and install flows on the switches to optimize traffic. Currently, MAC-to-MAC flows are installed. ** reactive-flow-table-id *** The reactive flow will be installed on the specified flow table of each switch *** This field is only relevant when "is-learning-only-mode" is set to "false" ** reactive-flow-priority *** The reactive flow will be installed with the specified priority *** This field is only relevant when "is-learning-only-mode" is set to "false" ** reactive-flow-idle-timeout *** The reactive flow will timeout (removed from the switch) if the flow doesn't forward a packet for _x_ seconds *** This field is only relevant when "is-learning-only-mode" is set to "false" ** reactive-flow-hard-timeout *** The reactive flow will timeout (removed from the switch) after _x_ seconds, regardless of how many packets it is forwarding *** This field is only relevant when "is-learning-only-mode" is set to "false" === Running the L2Switch project ==== Check out the project using git git clone https://git.opendaylight.org/gerrit/p/l2switch.git The above command will create a directory called "l2switch" with the project. ==== Run the distribution To run the base distribution, you can use the following command ./distribution/base/target/distributions-l2switch-base-0.1.0-SNAPSHOT-osgipackage/opendaylight/run.sh If you need additional resources, you can use these command line arguments: -Xms1024m -Xmx2048m -XX:PermSize=512m -XX:MaxPermSize=1024m' To run the karaf distribution, you can use the following command: ./distribution/karaf/target/assembly/bin/karaf === Create a network using mininet sudo mn --controller=remote,ip= --topo=linear,3 --switch ovsk,protocols=OpenFlow13 sudo mn --controller=remote,ip=127.0.0.1 --topo=linear,3 --switch ovsk,protocols=OpenFlow13 The above command will create a virtual network consisting of 3 switches. Each switch will connect to the controller located at the specified IP, i.e. 127.0.0.1 sudo mn --controller=remote,ip=127.0.0.1 --mac --topo=linear,3 --switch ovsk,protocols=OpenFlow13 The above command has the "mac" option, which makes it easier to distinguish between Host MAC addresses and Switch MAC addresses. === Generating network traffic using mininet h1 ping h2 The above command will cause host1 (h1) to ping host2 (h2) pingall 'pingall' will cause each host to ping every other host. === Checking Address Observations Address Observations are added to the Inventory data tree. The Address Observations on a Node Connector can be checked through a browser or a REST Client. http://10.194.126.91:8080/restconf/operational/opendaylight-inventory:nodes/node/openflow:1/node-connector/openflow:1:1 .Address Observations image::l2switch-address-observations.png["AddressObservations image",width=500] === Checking Hosts Host information is added to the Topology data tree. * Host address * Attachment point (link) to a node/switch This host information and attachment point information can be checked through a browser or a REST Client. http://10.194.126.91:8080/restconf/operational/network-topology:network-topology/topology/flow:1/ .Hosts image::l2switch-hosts.png["Hosts image",width=500] === Checking STP status of each link STP Status information is added to the Inventory data tree. * A status of "forwarding" means the link is active and packets are flowing on it. * A status of "discarding" means the link is inactive and packets are not sent over it. The STP status of a link can be checked through a browser or a REST Client. http://10.194.126.91:8080/restconf/operational/opendaylight-inventory:nodes/node/openflow:1/node-connector/openflow:1:2 .STP status image::l2switch-stp-status.png["STPStatus image",width=500] === Miscellaneous mininet commands link s1 s2 down This will bring the link between switch1 (s1) and switch2 (s2) down link s1 s2 up This will bring the link between switch1 (s1) and switch2 (s2) up link s1 h1 down This will bring the link between switch1 (s1) and host1 (h1) down