Hello, please elaborate a little bit more what you mean with "slow down the entire network".
What do you mean with "entire network"?
Do you really mean that any connection to any host within your entire LAN (eventually, through your local default gateway, with Internet too) is slowing down OR do you really mean that only connections from any host to the Server are slowing down?
If the former case is true then there is something very strange actually going on whitin your network since a file transfer generated by one host to/from Server (seen as another host) can saturate involved ports bandwitdhs but shouldn't slown down other traffic managed by your Switch.
If the latter case is true (only connections from any host to your Server WHEN an host is uploading/downloading big files to it) then the culprit could be (1) that the Server's NIC (Network Interface Card) isn't able to sustain other sessions (queueing them) while it's serving the data transfer sessions related to the upload/download from that particular host (so, literally, that host is "saturating" the NIC physical port of the Server)...and/or (2) the Server is unable to sustain workload generated by such files transfers.
Questions to answer:
- Which Server type you have (Manufacturer/Model)?
- Which NIC it has?
- How many physical ports the Server NIC has?
- What OS the Server is operating?
- What services that Server is serving to your hosts?
- How it is connected to the LAN (single link, aggregated link)?
- What is the Network topology of you entire network?
- What exact Model your Switch is?
- What software version your Switch is currently running on?
- Can you reproduce the issue? I mean: it happens exactly and only when that host (or any other choosen randomly) performs that file transfer action?