"Excessive Number of Collided Packets" on SLR5700 Repeater

[sjaltavilla]

I'm currently pulling my hair out dealing with my Linked Capacity Plus master repeater (SLR5700) which is constantly generating "Excessive Number of Collided Packet" alarms. I am noticing that this repeater seems to be pulled out of the trunking pool when this occurs. Out of all of my repeaters, this is the only one with the issue.

I have eliminated this being an IP / network issue and I am leaning towards believing this is RF related - whether it be interference or otherwise. That being said, however, I have checked all antenna connections and run a check with an SDR for major interference right at the repeater site and found nothing.

Has anyone else seen this before? The aforementioned alarm isn't even supported within RDAC - the only way I'm able to see it is with SmartPTT Monitoring. I've raised a ticket directly with Motorola and am currently in the midst of back and forth with RDS logs and codeplugs. But any additional thoughts would be appreciated.

 

[Firebuff880]

It will be interesting to see what you get from Tech Support but in looking at the SLR5700 Alarms, that's not one of them. You must be fairly current with your Repeater Firmware to get them to open a case, so that's [probably not the issue.

I suspect you have an issue with the software, (Sold & Supported) not the repeater. However, there is a "new" version of RDAC out with M2024.02 that you might try.

I will say that the text of the alarm "Excessive Number of Collided Packet" implies SIP Multicast traffic on other data traffic on your LAN with the software being unhappy, not a repeater issue. So why do you think it's a repeater issue?

 

[sjaltavilla]

I suspect you have an issue with the software, (Sold & Supported) not the repeater. However, there is a "new" version of RDAC out with M2024.02 that you might try.

I also raised a ticket with SmartPTT and they told me to reach out to Motorola. Classic 'finger-point' situation.

I will say that the text of the alarm "Excessive Number of Collided Packet" implies SIP Multicast traffic on other data traffic on your LAN with the software being unhappy, not a repeater issue. So why do you think it's a repeater issue?

I have run numerous Wireshark captures both on the MNIS side and the repeater LAN side with no indications of packet collisions, duplicate IPs, or anything else that might hinder the operation of the system. I have run constant pings between sites and to the individual rest channel IPs and found no indications there either.

Probably worth noting that I have configured the system to operate on it's own separate VLAN and have made sure that there is nothing blocking the UDP ports that are configured for the individual repeaters. That being said, I'm no network engineer by any means LOL.

The SmartPTT team suggested I look at the repeater / RF side as well. Based on what I've found thus far, I'm leaning closer towards that side. I'm hitting a wall trying to identify the cause because this just started happening recently and quite literally nothing has changed...

 

[Tech21]

Usually a duplex mismatch between repeater and switch.

Lock the port and repeater down to 100FD and see if yous still get alarms.

Also a bad patch cable could cause this.

 

[sjaltavilla]

Usually a duplex mismatch between repeater and switch.

Lock the port and repeater down to 100FD and see if yous still get alarms.

Also a bad patch cable could cause this.

I just gave this a try this morning. Confirmed the patch cable is solid. Locked just the master repeater and its corresponding switch port down to 100 Mbps full duplex. So far so good, but the load on the system today is quite light... I'll leave it through the weekend and see what ends up happening.

If this doesn't fix it, I'm thinking it might be the network card on the repeater.

 

[sjaltavilla]

Locking down the ports did not seem to have an effect on this issue. Still getting alarms. Ugh.

 

[Firebuff880]

@sjaltavilla

Just thought I would check back with you to see if you were able to get this resolved and what you found if anything

 

[sjaltavilla]

Apologies for going quiet. Crazy busy around here recently.

I believe I have solved this issue - knock on wood - as it has not happened in almost a month. I had eliminated it being a hardware problem as it started to occur on my second site as well. Upon further examination of my codeplugs (after Motorola had prematurely closed my support ticket), I found that the NTP settings for a couple of the repeaters were off by a few hours.

After I had reset the time settings, everything seemed to fix itself. Not sure if that was the primary issue, but definitely a contributing factor. I occasionally get a one-off packet collision, but so far, they have co-aligned with receive frequency interference - which actually makes sense.