Is PCIE Full Duplex?

[CerealExperimentsLain]

So, I have an ASRock ITX J4005 mobo arriving today for a pfSense build.  It will be using a PCIE enterprise NIC which I hope to upgrade later as my internet speeds up.  This will be a pfSense box that could likely see service until 2030 or so.

 

Anyway, the PCIE slot is mechanically x16 but electrically only x2 and that's PCIE 2.0. That's 1000MB/s of bandwidth or 8000mbps.  Assuming this is using a dual NIC PCIE controller for 'multi gigabit' operatoin, and I can also swap in SFP+ networking.  Right now I use a media converter for my fiber connection that converts it to copper before going into my router.

 

So... is PCIE full duplex?  Would that be 1000MB/s total bandwidth, in and out or is it can it do 1000MB/s each way concurrently in a full duplex operation? Being a network device, any bandwidth going in to the WAN port would then have to come out of the LAN port.  If it's not full duplex, then the on paper max bandwidth of the pfSense box would be half, or 500MB/s or 4000mbps... Or is it 1000MB/s or 8000mbps?

[Lurick]

Yes, PCIe is full duplex

[CerealExperimentsLain]

Just now, Lurick said:

Yes, PCIe is full duplex

Ah, cool, then the on paper maximum of the pfSense box would be 8000mbps, or better described as 'Far more bandwidth in the box than I will have in consumer internet bandwidth for years and year and years, even with fiber'.