Mac Ping; Mac Trace - Alcatel-Lucent 7750 SR OS Service Manual

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MAC Ping

For a MAC ping test, the destination MAC address (unicast or multicast) to be tested must be
specified. A MAC ping packet can be sent through the control plane or the data plane. When sent
by the control plane, the ping packet goes directly to the destination IP in a UDP/IP OAM packet.
If it is sent by the data plane, the ping packet goes out with the data plane format.
In the control plane, a MAC ping is forwarded along the flooding domain if no MAC address
bindings exist. If MAC address bindings exist, then the packet is forwarded along those paths (if
they are active). Finally, a response is generated only when there is an egress SAP binding to that
MAC address. A control plane request is responded to via a control reply only.
In the data plane, a MAC ping is sent with a VC label TTL of 255. This packet traverses each hop
using forwarding plane information for next hop, VC label, etc. The VC label is swapped at each
service-aware hop, and the VC TTL is decremented. If the VC TTL is decremented to 0, the
packet is passed up to the management plane for processing. If the packet reaches an egress node,
and would be forwarded out a customer facing port, it is identified by the OAM label below the
VC label and passed to the management plane.
MAC pings are flooded when they are unknown at an intermediate node. They are responded to
only by the egress nodes that have mappings for that MAC address.

MAC Trace

A MAC trace functions like an LSP trace with some variations. Operations in a MAC trace are
triggered when the VC TTL is decremented to 0.
Like a MAC ping, a MAC trace can be sent either by the control plane or the data plane.
For MAC trace requests sent by the control plane, the destination IP address is determined from
the control plane mapping for the destination MAC. If the destination MAC is known to be at a
specific remote site, then the far-end IP address of that SDP is used. If the destination MAC is not
known, then the packet is sent unicast, to all SDPs in the service with the appropriate squelching.
A control plane MAC traceroute request is sent via UDP/IP. The destination UDP port is the LSP
ping port. The source UDP port is whatever the system gives (note that this source UDP port is
really the demultiplexor that identifies the particular instance that sent the request, when
correlating the reply). The source IP address is the system IP of the sender.
7750 SR OS Services Guide
MAC Populate — Allows specified MAC addresses to be injected in the VPLS service
domain. This triggers learning of the injected MAC address by all participating nodes in
the service. This tool is generally followed by MAC ping or MAC trace to verify if correct
learning occurred.
MAC Purge — Allows MAC addresses to be flushed from all nodes in a service domain.
OAM and SAA
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