Symptom

When a GLC-LH-SMD 1G SFP transceiver inside of a CVR-QSFP-SFP10G (QSA) QSFP+ transceiver is inserted in a 40G QSFP+ interface of a Nexus 3100 device, the link may not reliably come up/up as expected within NX-OS. This symptoms can particularly be observed after a reload of the Nexus 3100 device, although other scenarios exist where the interface may not come up as expected. The device at the remote end of the down/down link may report that the link is up/up as expected. Furthermore, the RX/ingress counters of the affected interface on the Nexus 3100 device may report that traffic is being received, while the TX/egress counters of the affected interface do not report any traffic being sent out of the link.

Conditions

+++ Nexus 3100 device connected to a link. +++ Nexus 3100 has a GLC-LH-SMD 1G SFP transceiver inside of a CVR-QSFP-SFP10G (QSA) QSFP+ transceiver inserted in a 40G QSFP+ interface. +++ From Nexus 3100 device's perspective, the relevant interface for this link is down/down. +++ From the remote device's perspective, the relevant interface for this link is up/up. +++ The Nexus 3100 reports incrementing RX/ingress counters, but non-incrementing TX/egress counters.

Workaround

+++ Bouncing the affected interface using the following configuration brings up the link: Switch# configure terminal Switch(config)# interface Ethernet1/49/1 Switch(config-if)# shutdown Switch(config-if)# no shutdown

Further Problem Description