[CentOS] hosts fail to negotiate 1000Mbps speed

[nethub at gmail.com]

Akop Pogosian wrote:
> I am trying to connect two workstations (CentOS 3&4) directly using a
> straight through cat 5e cable with a crossover adapter on one of the
> ends. Both hosts have gigabit-capable ethernet card. According to
> lspci host 1 has:
>
> 03:0e.0 Ethernet controller: Intel Corporation 82545EM Gigabit
> Ethernet Controller (Copper) (rev 01)
>
> and host 2 has:
>
> 05:00.0 Ethernet controller: Marvell Technology Group Ltd. 88E8050
> Gigabit Ethernet Controller (rev 17)
>
> In order to get this controller work on host 2, I had to download and
> install a more recent version of the sk98lin driver. Host 2 runs
> CentOS 4. Host 1 runs CentOS 3 (with a stock e1000 driver).
>
> After I setup networking, ethtool reported for both hosts that the
> link runs at 100Mbps even though it says in both cases that the
> capability for 
> 1000baseT/Half 1000baseT/Full modes and exists and is being
> advertised. If I force 1000Mbps speed with "ethtool -s eth1  speed
> 1000", I get:
>
> # ethtool eth1
> Settings for eth1:
>         Supported ports: [ TP ]
>         Supported link modes:   10baseT/Half 10baseT/Full 
>                                 100baseT/Half 100baseT/Full 
>                                 1000baseT/Half 1000baseT/Full 
>         Supports auto-negotiation: Yes
>         Advertised link modes:  1000baseT/Half 1000baseT/Full 
>         Advertised auto-negotiation: No
>         Speed: Unknown! (65535)
>         Duplex: Unknown! (255)
>         Port: Twisted Pair
>         PHYAD: 0
>         Transceiver: internal
>         Auto-negotiation: on
>         Supports Wake-on: g
>         Wake-on: g
>
> and the eth1 link stops working. What could be a problem here? I tried
> loading both drivers with the parameter for 1000Mbps speed parameters
> but that didn't help.
>
> ( I used on host 1, alias eth1 e1000 Speed=1000
>  host 2, alias eth1 sk98lin Speed_A=1000 Speed_B=1000)
>   
Are you using a 1000 Mbps compatible crossover adapter?  For 1000 Mbps 
to function, it needs two pairs to be crossed-over -- see 
http://www.cabling-design.com/references/pinouts/1000base_t_crossover.shtml 
for the proper pin layout.  HTH.