[PLUG] Baffled: CentOS 7 DHCP 10G fast, fixed 1G

[Tomas Kuchta]

It seems that you are on the way to discover that the 10gb link is fine,
but your bits go through the 1gb interface.

If that is the case, you have some decisions to make about network
config/routing. You can check how your DHCP client avoids it, perhaps it
simply let's the 1gb interface unassigned, or it is by order...

Tomas


On Thu, Nov 14, 2019, 06:52 Michael Dexter <dexter at pdxlinux.org> wrote:

> On 11/13/19 1:07 PM, alan at clueserver.org wrote:
> > What does ethtool tell you?
>
> "DHCP" via network-scripts:
>
>   Settings for p2p1:
> Supported ports: [ TP ]
> Supported link modes:   100baseT/Full
>                          1000baseT/Full
>                          10000baseT/Full
> Supported pause frame use: Symmetric
> Supports auto-negotiation: Yes
> Advertised link modes:  100baseT/Full
>                          1000baseT/Full
>                          10000baseT/Full
> Advertised pause frame use: Symmetric
> Advertised auto-negotiation: Yes
> Speed: 10000Mb/s
> Duplex: Full
> Port: Twisted Pair
> PHYAD: 0
> Transceiver: external
> Auto-negotiation: on
> MDI-X: Unknown
> Supports Wake-on: d
> Wake-on: d
> Current message level: 0x00000007 (7)
>        drv probe link
> Link detected: yes
>
> iperf3 sample:
>
> [  4]   0.00-1.00   sec   114 MBytes   955 Mbits/sec    0    375 KBytes
>
> [  4]   1.00-2.00   sec   113 MBytes   946 Mbits/sec    0    375 KBytes
>
>
>
> $ sudo dhclient p2p1
> [cecheverri at rbx-1 ~]$ sudo ethtool p2p1
> Settings for p2p1:
> Supported ports: [ TP ]
> Supported link modes:   100baseT/Full
>                          1000baseT/Full
>                          10000baseT/Full
> Supported pause frame use: Symmetric
> Supports auto-negotiation: Yes
> Advertised link modes:  100baseT/Full
>                          1000baseT/Full
>                          10000baseT/Full
> Advertised pause frame use: Symmetric
> Advertised auto-negotiation: Yes
> Speed: 10000Mb/s
> Duplex: Full
> Port: Twisted Pair
> PHYAD: 0
> Transceiver: external
> Auto-negotiation: on
> MDI-X: Unknown
> Supports Wake-on: d
> Wake-on: d
> Current message level: 0x00000007 (7)
>        drv probe link
> Link detected: yes
>
> iperf3 sample:
> [  4]   0.00-1.00   sec  1.10 GBytes  9.41 Gbits/sec    0   1.23 MBytes
>
> [  4]   1.00-2.00   sec  1.10 GBytes  9.42 Gbits/sec    3   1.14 MBytes
>
> [  4]   2.00-3.00   sec  1.09 GBytes  9.40 Gbits/sec    3   1.14 MBytes
>
>
> So, identical ethtool output unless I'm missing something?
>
> Maybe responsible: There are two NICs on the same subnet as not to get
> locked out. Some OSs tolerate this while some do not. Because "dhclient"
> addressing works fine, I trust that is okay but the plan is to next try
> it without the 1GbE interface connected.
>
> Other ideas?
>
> In short, 'dhclient <interface>' gives a solid 10GbE. DHCP via
> network-scripts drops to 1GbE.
>
> Michael
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