Avaya 8800 Planning And Engineering, Network Design page 105

• The SLPP-PDU destination MAC address is the switch MAC address (with the multicast bit set)
and the source MAC address is the switch MAC address.
• The SLPP-PDU is sent out as a multicast packet and is constrained to the VLAN on which it is
sent.
• If an MLT port receives an SLPP-PDU the port goes down.
• The SLPP-PDU can be received by the originating CP or the peer SMLT CP. All other switches
treat the SLPP-PDU as a normal multicast packet, and forward it to the VLAN.
• SLPP-PDU transmission and reception only operates on ports for which STP is in a forwarding
state (if STP is enabled on one switch in the path).
• SLPP is port-based, so a port is disabled if it receives SLPP-PDU on one or more VLANs on a
tagged port. For example, if the SLPP packet receive threshold is set to 5, a port is shut down if
it receives 5 SLPP-PDU from one or more VLANs on a tagged port.
• The switch does not act on any other SLPP packet but those that it transmits.
• Enable SLPP-Rx only on SMLT edge ports, and never on core ports. Do not enable SLPP-Rx
on SMLT IST ports or SMLT square or full-mesh core ports.
• In an SMLT Cluster, Avaya recommends an SLPP Packet-RX Threshold of 5 on the primary
switch and 50 on the secondary switch.
• The administrator can tune network failure behavior by choosing how many SLPP packets
must be received before a switch takes action.
• SLPP-Tx operationally disables ports that receive their own SLPP packet.
The following table provides the Avaya recommended SLPP values.
Table 21: SLPP recommended values
Enable SLPP
Access SMLT
Access SLT
Core SMLT
IST
Primary switch
Packet Rx threshold
Transmission interval
Ethertype
Secondary switch
Packet Rx threshold
Transmission interval
Ethertype
June 2016
Setting
Yes
Yes
No
No
5
500 milliseconds (ms) (default)
Default
50
500 ms (default)
Default
Planning and Engineering — Network Design
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SLPP, Loop Detect, and Extended CP-Limit
105