Figure 19 Slpp Frame; Table 6 Slpp Frame Fields - Nortel 8300 User Manual

When you configure and enable SLPP, the switch control processor (CP)
sends an SLPP-PDU to the VLAN. If a loop exists on the VLAN, the
SLPP-PDU eventually returns to the originating port and is received by
the CP. The CP disables that port and a message appears on the console
describing why the port is disabled. A disabled port remains disabled until
you enable it. You can use the port auto enable feature to enable the port
after a predefined interval.
Figure 19 "SLPP frame" (page 53)
Figure 19
SLPP frame
Table 6 "SLPP frame fields" (page 53)
frame.
Table 6
SLPP frame fields
Field
DA
SA
PID
Payload
You must keep several factors in mind when you use SLPP:
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Configuration — VLANs, Spanning Tree, and Static Link Aggregation using Device Manager
Copyright © 2005-2007, Nortel Networks
.
SLPP-PDUs are forwarded on an individual VLAN basis.
SLPP-PDU reception and processing operates on a port only if
SLPP-RX is enabled on that port.
SLPP-PDUs are automatically forwarded on all ports of the VLANs that
are configured for SLPP.
The SLPP-PDU is sent out as a multicast packet and is constrained
to the VLAN on which it is sent.
The SLPP-PDU payload contains the VLAN ID. A separate SLPP-PDU
is sent for each VLAN.
Nortel Ethernet Routing Switch 8300
NN46200-510 03.01 Standard
4.0 27 August 2007
Simple Loop Prevention Protocol 53
shows the fields of an SLPP-PDU frame.
describes the fields of the SLPP
Description
destination MAC address (the switch MAC
address with the multicast bit set)
source MAC address (the switch MAC address)
user-configurable protocol ID (the default is
0x8104)
contains three fields:
1. SLPP protocol version (one byte)
2. reserved (one byte)
3. VLAN ID (two bytes)