Mirror Services612FD 100/320Gbps NT and FX NT IHub Services Guide3HH-11985-AAAA-TQZZA Issue: 13Nokia’s implementation of packet mirroring is based on two assumptions:• Packets in ingress direction are mirrored as they appear on the wire. This isimportant for troubleshooting encapsulation and protocol issues. When mirroringat ingress, the HW sends an exact copy of the original ingress packet to the mirrordestination while normal forwarding proceeds on the original packet.• Packets in egress direction are not always sent as seen on the wire. Egressmirroring is already performed in the ingress port. Packets will be send out on themirror to port always VLAN tagged and this VLAN is taken from the ingress port.Packets arriving untagged at the ingress port will be tagged using the ingress portPVID. This means that if VLAN translation is done for the packet while travelingfrom ingress to egress port that this will not be visible in the mirrored packet. If themirror SAP has a VLAN tag different from 0 then the mirrored packet will be dualtagged.8.2.1 Mirror Source and DestinationsMirror sources and destinations have the following characteristics:• A mirror source can be defined on each port.• A single mirror destination can be defined. Mirrored packets that are sent out canbe encapsulated with a configurable VLAN.8.2.2 Mirroring ConfigurationConfiguring mirroring is similar to creating a uni-direction service. Mirroring requiresthe configuration of:• Mirror source — The traffic on a specific point(s) to mirror.• Mirror destination — The location to send the mirrored traffic, where the sniffer willbe located.Figure 35 shows a local mirror service configured on ALA-A.• Port 2/1/2 is specified as the source. Mirrored traffic ingressing and egressing thisport will be sent to port 2/1/3.• SAP 2/1/3 is specified as the destination. The sniffer is physically connected tothis port. Mirrored traffic ingressing and egressing port 2/1/2 is sent here.
