Avaya Simple Loop Prevention Protocol

Simple Loop Prevention Protocol (SLPP) in computer networking is a layer 2 protocol invented by Nortel (previously acquired by Avaya, now acquired by Extreme Networks) to protect against 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. Once a loop is detected, the port is shut down.

Compatible equipment

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

Commands

Commands on two core ERS-8600 switches in a switch cluster.

• ERS 8600 Core Switch A

ERS-8610:5# config slpp add 200

ERS-8610:5# config slpp operation enable

ERS-8610:5# config ethernet 2/1-2/30 slpp packet-rx enable

ERS-8610:5# config ethernet 2/1-2/30 slpp packet-rx-threshold 10

• ERS 8600 Core Switch B

ERS-8610:5# config slpp add 200

ERS-8610:5# config slpp operation enable

ERS-8610:5# config ethernet 4/1-4/30 slpp packet-rx enable

ERS-8610:5# config ethernet 4/1-4/30 slpp packet-rx-threshold 50

See also

• Avaya
• Avaya Government Solutions
• VLACP
• SMLT
• RSMLT
• Loop (telecommunication)

Further reading

• Lin, Chuh Yu (San Jose, CA, US), Lapuh, Roger (Uesslingen, CH) (October 4, 2007). United States Patent 20070230357. United States Patent and Trademark Office. http://www.freepatentsonline.com/y2007/0230357.html. 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