SPT-C1 ports are not going down when mismatching.
Hi Team, One of my Customer having SPT-C1-1G. Connected back to back. When disabled Auto-Negotiation selected as 100Mbps, both ports came up fine. Now when changed one of the port to 10Mbps, link on the 100Mbps side goes down. But link on 10Mbps still stays up. When we mismatch the link speed, the side on 10Mbps stays up, but 100Mbps goes down. So customer wants to know why this is occurring in 10Mbps side. Are there any specification on the IEEE. Attached is the Webex recording. Please advise
This is a known "Ethernet" issue. The 10Mbps side misinterprets the 100Mbps FLPs as 10Mbps NLPs and therefore thinks it has a link.
Hi Larry, Thanks for the Response. But the customer tried with CM-1G-D12 and both the ports(10 and 100Mbps) are going offline. Please advise on why C1-Nic33 is not going down, while CM module goes down. Regards, Syed
Hello Larry, The behavior is different for C1 x 1G appliance and a CM-1G card. For the same trials as we tried in C1, **both ends of link are going down when a CM-1G card is used,** unlike one end staying up in C1 Do we have an explanation on why the CM card is giving a different behavior? Somewhere I have seen that CM card has some differences in terms of link establishments. Thanks, Sreerag
Let me restate that this is known behavior so the customer should not really be complaining. The ownness is on them to always verify the physical layer both from their settings and the resulting link state. I did see this with the CM-1G also with this twist. First, I unset autoneg and set port 1 to 10Mbps and port 2 to 100Mbps; port 1 showed link. I then flipped them and neither port showed link. I then set them back to auto and both showed link of course. I then set either to 10 and the other to 100 and the 10 port did not show link. So yes, the CM-1G does experience this phenomenon too.
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