During troubleshooting activities, different tools are used to determine the cause of a problem. Mirroring is also a troubleshooting tool for these activities. In Nokia (Alcatel-Lucent) world, mirroring term corresponds “Service Mirroring”.
As you can understand from the maining, basically, mirroring means copying the same data to another place that we can analyze. Servise Mirroring, is also such a mirroring facility. Customer Service is mirrored from one port to another and after that the required analyze is done.
Service Mirroring can be in two types. These are:
• Local Mirroring
• Remote Mirroring
Local Mirroring is done within a single device.
Remote Mirroring is done remotely,by using multiple devices.
One Service Mirroring can be used through ingress or egress direction on a SAP in Local Mirroring. In Remote Mirroring this is done through SDPs. SAPs are used in Remote Mirroring too.
Multiple Mirrored Services can be received from a port. But to receive this, this port need to be configured with dot1q. Here, dot1q provide this distinction.
There are two important points in Service Mirroring. These points are:
• Mirror Source
• Mirror Destination
Mirror Source is the location that we would like to analyze its traffic.
Mirror Destination is the location that we send the traffic to analze.
A Mirror Source can have only one Destination. But a Mirror Destination can receive mirrored traffic from multiple Mirror Source.
Service Mirroring causes some traffic increases. To avoid this “Slicing” is used. With this mechanims, Mirrored traffic is send from one router to another with smaller bytes. To configure Slicing, we can use “slice-size size” command, under the Mirror Destination.
With specific examples of Local Mirroring and Remote Mirroring, you will understand Service Mirroring better.