300SS, detect CRC errors

Hi, another question.
We installed many of point-2-point links with 300SS protection at every BTS. However, seems like the 300SS was incompatible with most of the Cisco switches such as 2960, 3750 and etc…

My wiring installation like this:
Radio CAT5e > 300SS jack1 > 300SS jack2 > cisco port, 10AWG 6mm2 connected to MGB.

But the interface of cisco port detected a lot of input errors and CRC errors. So i found this problem and then bypass all the 300SS that i installed. Now, the errors disappeared.

Anyone can suggest that how to protect both end equipment from lightning?

Was the Cisco configured for Auto? Try forcing to 100Mbps Full - it may have been the Cisco Ethernet port was flapping

Jerry Richardson wrote:
Was the Cisco configured for Auto? Try forcing to 100Mbps Full - it may have been the Cisco Ethernet port was flapping


Yes, cisco is speed/duplex auto. When show log, there is no flapping on that interface.

If i force interface to 100F, how about canopy ethernet? Need forced to 100F also?

try forcing just the cisco - leave the canopy set to auto. If you force it and it locks up you will have to access the radio with a default plug.

Jerry Richardson wrote:
try forcing just the cisco - leave the canopy set to auto. If you force it and it locks up you will have to access the radio with a default plug.


I'll try your method,

Forced cisco interface to 100F, leave auto for canopy.
Let's see what happen.

I can almost promise you that you’ll see an end when you force the speed and duplex on the Cisco to 100/full

I have a site that uses the 300ss protectors and found when using those sometimes you get errors on the 802.3 interface. Forcing the port to a particular speed and duplex resolves the issue.

amd phreak wrote:
I can almost promise you that you'll see an end when you force the speed and duplex on the Cisco to 100/full

I have a site that uses the 300ss protectors and found when using those sometimes you get errors on the 802.3 interface. Forcing the port to a particular speed and duplex resolves the issue.


Okay, thanks for the info.

reeyon, what ended up being your solution here?

Okay. Here is my conclusion.

My run test error steps:
1. Forced Cisco port to speed 100 duplex full. Canopy sometimes will detects auto 100/Half(bug?), so I forced canopy to 100/full as well, now I can’t see any input errors/CRC errors in Interface status.

2. Forced cisco port to 100/full, canopy detects auto 100/full. CRC gone.

3. Forced canopy to 100/full, leave cisco auto 100/full. CRC errors appeared.

Now all my Canopys with 300SS which connected to Cisco interface, both canopy & cisco interface forced to 100/full. CRC gone. :slight_smile:

Whenever you have a Cisco involved, 100/Full is strongly recommended. As part of the IEEE 802.3u standard (which is often subject to interpretation), whenever you turn off autonegotiation the other end will fall back to half-duplex.

Best practice is 100/Full on both sides.