##Nettverkslaget og linklaget ##SDN ### Historie ### Hva er SDN ### Motivasjon ### Kontroller ### Openflow ##Ruting protokoller ###RIP ###Open Shortest Path First (OSPF) ##Border Gateway Protocol (BGP) ###Attributes ####ORIGIN -tells the receiver the type of original src of NLRI inf ####AS_PATH -contains a list of ASs traversed ####NEXT_HOP -defines the IP-address of the next-hop router to be used for the next hop for all dsts listed in the NLRI field of the UPDATE message ####MULTI_EXIT_DISC (kun i eBGP) -the lower the MED value, the more preferred the route will be ####LOCAL_PREF (kun i iBGP) -the higher the local preference value, the more preferred the route ####ATOMIC_AGGREGATE -indicates that an AS is passing a less specific --rather than more specific-- route ####AGGREGATOR -contains the last AS number that formed the aggregate route, followed by the IP address of the BGP speaker that formed the aggregate route ####COMMUNITIES -routes that share some common property -a route can be tagged with more than one community ####EXTENDED COMMUNITIES ####ORIGINATOR_ID -supports the route reflector feature used for scaling iBGP meshes -identifies the src of routes ####CLUSTER_LIST -supports the route reflector feature used for scaling iBGP meshes -a mini-AS_PATH used to detect updates that are looping inside the cluster ####Multiprotocol Reachable NLRI ####Multiprotocol Unreachable NLRI ###BGP States ####Idle The router isn't trying to set up a BGP session, and if the neighbor were to attempt to create a session, the TCP connection would be refused. The router waits for a "start" event, typically the user enabling BGP or adding a neighbor or an interface coming up. ####Connect In this state, the router waits for its own TCP session establishment attempt to complete, and it listens for incoming TCP sessions ####Active BGP is waiting for a TCP session ####OpenSent The open message has been sent, but an open message hasn't yet been received from the neighbor. ####OpenConfirm The open message from the neighbor has been received, but not yet the initial keepalive message that completes the BGP session setup phase. ####Established The initial keepalive message has been received, and the session is now ready for transmission of update, keepalive, and notification messages. ###Routing Information Base (RIB) A routing table will only store one route per destination, while the RIB usually contains multiple routes. The RIB keeps track of routes that could possibly be used. If a route withdrawal is received and it only existed in the RIB, it is silently deleted from the RIB. No update is sent to peers. RIB entries never time out. They continue to exist until it is assumed that the route is no longer valid.