XGS-5240-Series User Manual

Configuration Guide of XGS-5240-Series
63-2
sed by the abnormity problem, the preemption delay mechanism is imported, and it nee
ds to wait for some times before the master port preempt the slave port. For keeping t
he continuance of the flows, the master port does not process to preempt by default, b
ut turns into the Standby state.
When configuring ULPP, it needs to specify the VLAN which is protected by this U
LPP group through the method of MSTP instances, and ULPP does not provide the pr
otection to other VLANs.
When the uplink switch is happennig, the primary forwarding entries of the device
will not be applied to new topology in the network. In the figure, SwitchA configures UL
PP, the portA1 as the master port at forwarding state, here the MAC address of PC is
learned by Switch D from portD3. After this, portA1 has the problem, the traffic is swit
ched to portA2 to be forwarded. If there is the data sent to PC by SwitchD, still the d
ata will be forwarded from portD3, and will be losed. Therefore, when switching the upli
nk, the device of configuring ULPP needs to send the flush packets through the port w
hich is switched to Forwarding state, and update MAC address tables and ARP tables
of other devices in the network. ULPP respectively uses two kinds of flush packets to
update the entries: the updated packets of MAC address and the deleted packets of A
RP.
For making use of the bandwidth resource enough, ULPP can implement VLAN loa
d balance through the configuration. As the picture illustrated, SwitchA configures two U
LPP groups: portA1 is the master port and portA2 is the slave port in group1, portA2 i
s the master port and portA1 is the slave port in group2, the VLANs are protected by
group1 and group2, they are 1-100 and 101-200. Here both portA1 and portA2 at the f
orwarding state, the master port and the slave port mutually backup, and respectively f
orward the packets of the different VLAN ranges. When portA1 has the problem, the tr
affic of VLAN 1-200 are forwarded by portA2. After this, when portA1 is recovering the
normal state, portA2 forwards the data of VLAN 101-200 sequentially, but the data of
VLAN 1-100 is switched to portA1 to forward.