PTP400 Ethernet connection drop

Has anyone seen this before?

PTP400 lite, 5.7G at 100’ on a steel tower. Altelicon AL-Cat6W surge arrestors on both ends of the shielded cat-5e ethernet run from radio to equipment room. Cisco Catalyst 2924 on the other end of the ethernet run.

Occasionally the Ethernet interface will drop out and immideately pick up again. Both sides of the link are hard set to 100M/FDX. Very few errors on the Ethernet interfaces.

Example from switch log:

Feb 26 08:25:19 2787: .Feb 26 08:25:11: %LINK-3-UPDOWN: Interface FastEthernet0/22, changed state to down
Feb 26 08:25:19 2788: .Feb 26 08:25:12: %LINK-3-UPDOWN: Interface FastEthernet0/22, changed state to up

This wreaks havoc with OSPF and causes a momentary blackhole that is obviously bad for VoIP traffic.

Anyone have any ideas?

My guess is that the surge arrestors are causing the loss of carrier sense.

Haven’t heard of anyone using 2 sets or surge protectors before

Also these don’t sound like the recommended surge protectors for Orthogon / Motorola PTP

2 sets is the recommended configuration from Motorola to prevent induced currents in long ethernet runs (from nearby lightning strikes) from burning out the ODU or the indoor equipment.

The Altelicon protector is not blessed by Motorola but it is designed for use with the PTP series radios (Orthogon) and I have them working on several other PTP400 links in the same configuration without any problems.