 address or UDP/TCP port, the other fields are irrelevant, and consequently those fields are wild carded. Table 1. Header fields used for matching flows in the flow table Ingress Ether Ether Ether Source Desti Source Desti Prior Source Desti Proto Downloaded 4/15/2022 9:44:49 AM Nova Southeastern University IP Address: 137.52.76.29 Quality of Service in SDN Technology Figure 4. Packet In clear action set initialise pipeline fields start at table 0 Update counters Execute action set : Match in Execute instruction set : Goto- update packet headers table ? update action set Table ? update match set fields update packet headers update pipeline fields update match set fields update pipeline fields as needed, clone packet to egress Group Table- action ? miss flow entry exists ? Drop packet Drop packet Output action ? Ingress Egress switch has egress tables ? Start egress processing action set . (output port) start at first egress table Update counters Execute action set : Match in Execute instruction set : Goto- update packet headers table ? update action set Table n ? update match set fields update packet headers update pipeline fields update match set fields update pipeline fields as needed. clone packet to egress Drop packet Output Table- action ? miss flow entry exists ? Packet Out Drop packet Each flow table contains entries consisting of six components as shown in Table 2. The preceding match fields must be supported by any Open Flow- compliant switch. The following fields may be optionally supported: Physical Port: Used to designate underlying physical port when packet is received on a logical port. Metadata: Additional information that can be passed from one table to another during the processing of a packet. Ethernet Type: Ethernet Type field. Downloaded 4/15/2022 9:44:49 AM Nova Southeastern University IP Address: 137.52.76.29 Quality of Service in SDN Technology Table 2. Flow table components Match Fields Used to select packets that match the values in the fields. Priority Relative priority of table entries.