8. Traffic MonitoringMN700004 Rev 01 68Traffic TypesA monitor session includes the following traffic types:• Receive (Rx) - The goal of receive (or ingress) monitoring is to monitor the packetsreceived by the source interface or VLAN before any modification or processing isperformed by the switch. A copy of each packet received by the source is sent to thedestination port that monitors the session. At the destination port, if the packet istagged, it will appear with the 802.1Q header.• Transmit (Tx) - The goal of transmit (or egress) monitor session is to monitor asmuch as possible all the packets sent by the source interface after all modification andprocessing is performed by the switch. A copy of each packet sent by the source issent to the destination port for that monitor session. The copy is provided after thepacket is modified.Source PortA source port (also called a monitored port) is a switched or routed port that you monitor fornetwork traffic analysis. In a single local monitor session, you can monitor source port trafficsuch as received (Rx), transmitted (Tx), or bidirectional.On the Rx the switch supports any number of source ports up to the maximum number ofavailable ports on the switch, and any number of source VLANs up to the maximum numberof VLANs supported.On the Tx the switch supports up to eight source ports.A source port has the following characteristics:• It can be any port type (for example, Fast Ethernet, Gigabit Ethernet, link aggregationgroup and so forth).• It cannot be a destination port.• Each source port can be configured with a direction (Rx, Tx, or both) to monitor.• Source ports can be in the same or different VLANs.For VLAN monitor sources, all active ports in the source VLAN are included as source ports.Destination PortEach local monitor session must have a destination port (also called a monitoring port) thatreceives a copy of traffic from the source ports and VLANs.The destination port has the following characteristics:• It must reside on the same switch as the source port.• It can be any Ethernet physical port.• It cannot be a source port.NOTE The destination port is limited to its capacity. All traffic that exceeds the port's capacity willbe dropped.
