Service Mirroring - Alcatel-Lucent 7750 SR OS Service Manual

Service Mirroring

Service Mirroring
When troubleshooting complex operational problems, customer packets can be examined as they
traverse the network. One way to accomplish this is with an overlay of network analyzers
established at multiple PoPs, together with skilled technicians to operate them to decode the data
provided. This method of traffic mirroring often requires setting up complex filters in multiple
switches and/or routers. These, at best, are only able to mirror from one port to another on the
same device.
Alcatel-Lucent's Service Mirroring extends and integrates these capabilities into the network and
provides significant operational benefits. Each 7750 SR can mirror packets from a specific service
to any destination point in the network, regardless of interface type or speed.
This capability also extends beyond troubleshooting services. Telephone companies have the
ability to obtain itemized calling records and wire-taps where legally required by investigating
authorities. The process can be very complex and costly to carry out on data networks. Service
Mirroring greatly simplifies these tasks, as well as reduces costs through centralization of analysis
tools and skilled technicians.
Alcatel-Lucent's 7750 SR routers support service-based mirroring. While some Layer 3 switches
and routers can mirror on a per-port basis within the device, Alcatel-Lucent 7750 SR routers can
mirror on an n-to-1 unidirectional service basis and re-encapsulate the mirrored data for transport
through the core network to another location, using either IP or MPLS tunneling as required
(Figure
Original packets are forwarded while a copy is sent out the mirrored port to the mirroring
(destination) port. Service mirroring allows an operator to see the actual traffic on a customer's
service with a sniffer sitting in a central location. In many cases, this reduces the need for a
separate, costly overlay sniffer network.
The mirrored frame size that is to be transmitted to the mirror destination can be explicitly
configured by using slicing features. This enables mirroring only the parts needed for analysis. For
example, only the headers can be copied for analysis, protecting the integrity and security of
customer data, or conversely, copying the full packet, including customer data.
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7750 SR OS Services Guide