Simple Loop Prevention Protocol

Simple Loop Prevention Protocol (SLPP) in computer networking is a data link layer protocol developed by Nortel (previously acquired by Avaya, now a part of Extreme Networks) to protect against Layer 2 network loops. SLPP uses a small hello packet to detect network loops. The SLPP protocol checks packets from the originating switch and the peer switch in a SMLT configuration. Sending hello packets on a per VLAN basis allows SLPP to detect VLAN based network loops for un-tagged as well as tagged IEEE 802.1Q VLAN link configurations. If a loop is detected, the associated port is shut down.

Compatible equipment

• Avaya VSP 9000 Series - Software version 3.0 or above
• Avaya VSP 7000 Series - Software version 10.0 or above
• Avaya ERS 8600 - Software version 4.1 or above
• Avaya ERS-8300 - Software version 4.0 or above
• Avaya ERS-5000 - Software version 6.3 or above
• Avaya ERS 4000 series - Software version 5.6.2 or above
• Avaya ERS-3500 - Software version 5.2.0 or above

See also

• VLACP

Further reading

• Lin, Chuh Yu; Lapuh, Roger (October 4, 2007). "United States Patent 20070230357". Free Patents Online. Retrieved 3 Sep 2011.
• Simple Loop Prevention Protocol Google Patents
• Simple Loop Prevention Protocol (SLPP)
• Nortel "Simple Loop Prevention Protocol" (SLPP)
• Switch Clustering Design Best Practices
• Quick Nortel MLT (Link Aggregation) Reference
• Switch Clustering Design Best Practices

External links

• Switch Clustering using Split Multi-Link Trunking (SMLT) with ERS 8600, 8300, 5x00 and 1600 Series Technical Configuration Guide