CRC/FCS errors on 10G links between MikroTik CRS switches and Cisco Catalyst 3750-X/2960-S
1
The poster runs temporary event networks and has twice hit heavy frame errors on 10G links between MikroTik and Cisco switches. About a year earlier a Cisco Catalyst 2960-S with 10G uplinks connected to a MikroTik CRS317-1G-16S+ showed CRC errors on the Cisco side and swapping cables did not help. At the current event a Catalyst 3750-X with a 10G module connected to a MikroTik CRS326-24S+2Q+RM shows FCS errors all over the place on the MikroTik side. The DAC had already been replaced by a brand-new fiber patch cord with two new SFP+ modules without improvement. The poster asked what to consider when negotiating such a cross-vendor 10G link.
- Hardware: Cisco Catalyst 3750-X with 10G network module, Cisco Catalyst 2960-S with 10G uplinks, MikroTik CRS326-24S+2Q+RM, MikroTik CRS317-1G-16S+
- Transceivers: unspecified 10G SFP+ DAC, unspecified 10G SFP+ optics (new pair)
- Form factor: SFP+, DAC
Symptoms / messages:
CRC errors on the Cisco 10G port
FCS errors on the MikroTik side
errors persist after replacing DAC with a new patch cord and new SFP+ modules
Comments 3
A respondent listed the usual layer-1 suspects (bad 3750-X port, bad cable, bad frames from the peer, NIC or SFP incompatibility between MikroTik and Cisco), advised hard-coding port settings on both devices instead of relying on negotiation, and suggested the Cisco commands 'service unsupported-transceiver' and 'no errdisable detect cause gbic-invalid' for third-party optics.
A respondent asked for the SFP+ model, the exact switch model and IOS version plus 'show version', 'show logging', 'show run interface', 'show interface' and 'show interface transceiver' output before any diagnosis.
Another respondent doubted the CRS326-24S+2Q+RM supports 10G at all (mistaken, since it has 24 SFP+ ports plus two QSFP+ ports) and asked for a photo of the setup. No resolution was posted.