We have a couple of 93180 switches running vPC as our core. A Cisco server is dual-homed to the core switches via a Ether-channel of 2 x 10Gbps (MTU 9216), the Internet is a single link of 1Gbps (MTU1500) into one of the switches. When I do speedtest, I got ~900Mbps down and ~900Mbps up, which is great, matches the expectation.
Here comes the problem, when I try to do speedtest from a local laptop on 1000Base-T (MTU 1500), I could only get ~500Mbps down and ~900Mbps up. This laptop is plugged into the switch directly, i.e. no middle devices. it's in the same subnet as the server and used identical DNS etc. settings.
I initially thought was it might be the FTD firewall, however, I disconnected the firewall and changed my IP to the firewall's, i.e. Laptop - Switch - Internet. I got the same speed ~500Mbps down and ~900Mbps up.
This makes me think is there any hardware or software limitation or mechanism on the switch that slows down the download speed?
Any thoughts would be highly appreciated.
BIOS: version 07. 61
NXOS: version 7. 0(3)17(3)
Cisco Nexus 9000 93180yc-ex chassis
Laptop Port Configuration:
interface Ethernet1/8
Switchport
switchport access vlan 8
no shutdown
Server Port Configuration:
interface port-channel18
switchport
switchport mode trunk
spanning-tree port type normal
spanning-tree guard root
mtu 9216
vpc 18
interface Ethernetl/38
switchport
switchport mode trunk
mtu9216
channel-group 10 mode active
no shutdown
