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)
-akop
* on the Wed, Jan 25, 2006 at 05:40:41PM -0800, Akop Pogosian was tippering:
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:
IIRC, one does not need a crossover cable to connect between two gigabit capable hosts.
You can give it a shot.
Bruno S. Delbono wrote:
- on the Wed, Jan 25, 2006 at 05:40:41PM -0800, Akop Pogosian was tippering:
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:
IIRC, one does not need a crossover cable to connect between two gigabit capable hosts.
You can give it a shot.
Perhaps I'm just dense, but how would two ethernet cards talk to eachother over a straight ethernet cable? I don't profess to be an expert in gigabit ethernet protocols, but I believe it HAS to be a crossover cable if you want to directly connect two hosts. If that's not the case, someone please correct me.
Best regards,
* on the Wed, Jan 25, 2006 at 08:54:56PM -0500, Chris Mauritz was tippering:
Bruno S. Delbono wrote:
- on the Wed, Jan 25, 2006 at 05:40:41PM -0800, Akop Pogosian was
tippering:
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:
IIRC, one does not need a crossover cable to connect between two gigabit capable hosts.
You can give it a shot.
Perhaps I'm just dense, but how would two ethernet cards talk to eachother over a straight ethernet cable? I don't profess to be an expert in gigabit ethernet protocols, but I believe it HAS to be a crossover cable if you want to directly connect two hosts. If that's not the case, someone please correct me.
From what I remember, perhaps this was an apple only thing. Apples implementation of Gigabit Ethernet needs no crossover cable to connect two computers together. The adapter senses the other Mac and handles the crossover automatically.
IIRC, one does not need a crossover cable to connect between two gigabit capable hosts.
Agreed I think gigabit ethernet adapters _have_ to be autosensing of MDI (normal) or MDI-X (crossover) to be considered gigabit capable (ie within specifications). I expect the crossover adapter may be causing enough interference to stop 1gbit from working thus resulting in merely 100 mbits.
Furthermore it is entirely possible that it's a 100mbit only crossover adapter: it might not be crossing all 8 lines since gigabit uses 8 lines and not 4 like 100mbit...
Cheers, MaZe.
Maciej Z.enczykowski wrote:
IIRC, one does not need a crossover cable to connect between two gigabit capable hosts.
Agreed I think gigabit ethernet adapters _have_ to be autosensing of MDI (normal) or MDI-X (crossover) to be considered gigabit capable (ie within specifications). I expect the crossover adapter may be causing enough interference to stop 1gbit from working thus resulting in merely 100 mbits.
This is new information for me.
Furthermore it is entirely possible that it's a 100mbit only crossover adapter: it might not be crossing all 8 lines since gigabit uses 8 lines and not 4 like 100mbit...
I suspect that may be the case here given the above "new" information.
Cheers,
} 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:
remove the crossover adapter and try again
- rh
-- Robert Hanson - Abba Communications Computer & Internet Services (509) 624-7159 - www.abbacomm.net
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.
On Wed, 2006-01-25 at 22:22 -0500, nethub@gmail.com wrote:
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.
The pinout shown on the above mentioned website crosses over all 4 pairs compared to a standard crossover which only crosses over the green and orange pairs (pins 1,2,3 and 6)
Our experience with GigE indicates that two hosts can communicate with a straight-thru or standard crossover cable (2 pairs). Host-to-switch cabling can be straight-thru or crossover as well.
The hardware in question is a Cisco 2960 and the Broadcom Corporation NetXtreme BCM5704 Gigabit Ethernet (tg3 driver).
Bob...
Apparently the network connection between these two hosts works with or without the cross-over adapter (which crosses two pairs of wires) at 100Mbps. Forcing 1000Mbps with ethtool does not work. However, the host with the Marvell Technology group ethernet adapter also has an Intel EtherExpress 1000 adapter. So, I tried connecting the cable to it and it worked instantly. There is probably some interoperability issue between Intel EE1000 and the Marvell adapter hardware and/or software.
-akop
-
Akop Pogosian -
Bob Chiodini -
Bruno S. Delbono -
Chris Mauritz -
Maciej Żenczykowski -
nethub＠gmail.com -
Robert Hanson