SMB Multichannel stuck in a disconnect loop with mixed 10G/25G NICs. Any elegant way to isolate adapter pools?

Chang Min 40 Reputation points
2026-07-14T04:46:00.2366667+00:00

Hi guys, reaching out to see if anyone has cracked this specific edge case.

We have a production server running a mixed-speed network config (two 10GbE and two 25GbE links). The issue is that SMB Multichannel is totally losing its mind over the asymmetric link speeds. Instead of aggregating gracefully, it’s constantly opening and dropping connections in an endless loop because the throughput calculation can't stabilize.

Obviously, the 10G links are dragging the whole behavior down. How do we force SMB Multichannel to selectively bind only to the 25GbE adapter pool and completely ignore the 10G interfaces?

Trying to avoid pulling the 10G cables physically as they are needed for other management traffic. Any clean workaround or standard cmdlet to restrict this pathing? Thanks in advance!

Windows for business | Windows Server | Networking | Network connectivity and file sharing
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Answer accepted by question author
HLBui 12,380 Reputation points Independent Advisor
2026-07-14T05:15:51.9266667+00:00

Hi Chang Min

Yes, SMB Multichannel can get pretty messy when you mix link speeds like that it tries to be “smart” but ends up thrashing connections because the throughput math never stabilizes. The clean way to handle this is to tell SMB to only use the faster NICs. You can do that by disabling multichannel on the 10GbE adapters with Set-SmbClientConfiguration -DisableMultiChannel $true or by tweaking the SMB Multichannel constraints so only the 25GbE interfaces are eligible. Another option is to use Interface Binding via PowerShell, where you explicitly bind SMB traffic to the NICs you want. That way, the 10G links can stay connected for management traffic but won’t be part of the SMB channel pool.

Some admins also prefer to separate management and data networks entirely with different subnets/VLANs, so SMB never even “sees” the slower adapters. Bottom line: you don’t need to pull cables just restrict SMB Multichannel to the 25GbE side and let the 10G links handle their own role.

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