Master-Slave Operation; Figure 24: Master-Slave Pseudowire Redundancy - Alcatel-Lucent 7210 SAS M Service Manual

Master-Slave Operation

NOTE: 7210 SAS devices support only standby-signaling-master option. 7210 does not support
the CLI command standby-signaling-slave. In the discussion below, reference to standby-
signaling-slave command is only used to describe the solution. 7210 device can be used only
where standby-signaling-master is used in the example below.
This section describes master-slave operation for pseudowire redundancy, as well as the algorithm
used to select the active transmit object in a VLL endpoint.
Blockin
covered in this section. A solution the Rx direction of standby spoke SDP at the master endpoint in
order to interoperate with PEs that play a slave role but do not support blocking the Tx direction
on receiving a standby. However, blocking Tx on standby is a feasible approach since blocking Tx
satisfies a majority of deployments.
Figure 24
Epipe service is provided between CE1 and CE2. CE2 is dual homed to PE2 and PE3, and thus
PE1 is dual-homed to PE2 and PE3 using Epipe spoke SDPs. The objectives of this feature is to
ensure that only one pseudowire is used for forwarding in both directions by PE1, PE2 and PE3 in
the absence of a native dual homing protocol between CE2 and PE2/PE3, such as MC-LAG. In
normal operating conditions (the SAPs on PE2 and PE3 towards CE2 are both up and there are no
defects on the ACs to CE2), PE2 and PE3 cannot choose which spoke SDP to forward on based on
the status of the AC redundancy protocol.
L2 Switch
CE1
standby-signaling-master
7210 SAS M Services Guide
g the transmit direction of a VLL spoke SDP when the far-end PE signals standby are
illustrates the operation of master-slave pseudowire redundancy. In this scenario, an
PE1

Figure 24: Master-Slave Pseudowire Redundancy

epipe
A
S
epipe
standby-signaling-slave
Virtual Leased Line Services
A
PE2
NO MC-LAG
CE2
A
PE3
Block
Fwd
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