XGS-5240-Series User Manual

Configuration Guide of XGS-5240-Series
63-1
Chapter 63 ULPP Configuration
63.1 Introduction to ULPP
Each ULPP group has two uplink ports, they are master port and slave port. The
port may be a physical port or a port channel. The member ports of ULPP group have
three states: Forwarding, Standby, Down. Normally, only one port at the forwarding sta
te, the other port is blocked at the Standby state. When the master port has the link p
roblem, the master port becomes down state, and the slave port is siwthed to forwardi
ng state.
Fig 4-1 the using scene of ULPP
The above figure uses the double-uplink network, this is the typical application sce
ne of ULPP. SwitchA goes up to SwitchD through SwitchB and SwitchC, port A1 and p
ort A2 are the uplink ports. SwitchA configures ULPP, thereinto port A1 is set as the m
aster port, port A2 is set as the slave port. When port A1 at forwarding state has the
problem, switch the uplink at once, port A2 turns into forwarding state. After this, when
recovering the master port, if the preemption mode is not configured, port A2 keeps th
e Forwarding state, port A1 turns into the Standby state.
After the preemption mode is enabled, so as to the master port preempts the slav
e port when it recovered from the problem. For avoiding the frequent uplink switch cau