Avaya 8800 Planning And Engineering page 109

• SLPP-PDUs are automatically forwarded VLAN ports configured for SLPP.
• 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 22: 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
Planning and Engineering — Network Design
SLPP, Loop Detect, and Extended CP-Limit
Setting
Yes
Yes
No
No
5
500 milliseconds (ms) (default)
Default
50
500 ms (default)
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