[nSLUG] Router won't do 100mbps locally

Warren Robertson WRobertson at dal.ca
Thu Feb 4 08:38:56 AST 2010


Always best to start with the basics, how are your cables, 100MB uses
all 4 pair.


On Thu, 2010-02-04 at 03:26 -0400, Mike Spencer wrote:
> So I finally got two computers with network cards that support
> 100baseT and which are responsive to ethtool.  They're cable-connected
> to a D-Link DI-713P router (advertised as 10baseT and 100baseT
> compliant.)
> 
> So, with ethtool, I force both cards to "autoneg off duplex full speed
> 100".  The blinkenlights on the router go into continuous twiddle
> mode.  No packets are detected by tcpdump.  So the cards are trying to
> establish a 100Mbps connection with the router at the Ethernet level
> (right?)  and failing (right?).
> 
> While this state continues, neither host is reachable from the other.
> A similar condition arises if I let the cards auto-negotiate. The
> blinkenlight twiddle never stops and no IP connection can be made
> between computers.
> 
> Resetting the cards with "ethtool....speed 10" results in a connection
> with an actual transfer rate (by calculation from a quickie script) of
> 9.1Mbps.
> 
> Is there some arcanum that I need to know?
> 
>          Example arcanum that I ruled out:
> 
>          Older routers may not support Explicit Congestion
>          Notification (RFC 3168) but sysctl shows this disabled in my
>          2.4 kernel and source code shows it as a disabled option in
>          the driver module.
> 
> Or is the best surmise that the router is failing (more or less)
> gracefully?
> 
> The router's admin interface doesn't have any means to force it to a
> particular speed.
> 
> FWIW, here's the tech info
> 
>   root# ethtool eth0
> 
>   Settings for eth0:
>     Supported ports: [ TP MII ]
>     Supported link modes:   10baseT/Half 10baseT/Full
>                             100baseT/Half 100baseT/Full
>     Supports auto-negotiation: Yes
>     Advertised link modes:  10baseT/Half 10baseT/Full
>                             100baseT/Half 100baseT/Full
>     Advertised auto-negotiation: No
>     Speed: 10Mb/s
>     Duplex: Full
>     Port: MII
>     PHYAD: 1
>     Transceiver: internal
>     Auto-negotiation: off
>     Current message level: 0x000020c1 (8385)
>     Link detected: yes
> 
> [Same for both cards. Everything works at ca. 10Mbps with these settings.]
> 
>   bogus-root# lspci |grep Ethernet
> 
>     01:08.0 Ethernet controller: Intel Corp. 82801BA/BAM/CA/CAM Ethernet
>             Controller (rev 01)
> 
>   nudel-root# lspci |grep Ethernet
> 
>     01:08.0 Ethernet controller: Intel Corporation 82562EZ 10/100 Ethernet
>             Controller (rev 02)
> 
> 
> Modules [both boxen]:
> 
>      eepro100
>      mii         [eepro100]
> 
> 
> Advice? TIA,
> - Mike
> 

-- 
Warren Robertson, CISS,CCAI
Systems Manager
Dalhousie University
Faculty of Engineering
Internetworking Program
1360 Barrington Street
2nd Floor, A Wing, Room A210
PO Box 1000
Halifax, NS, B3J 2X4
Tel: 902-494-6371 Fax: 902-494-2057
Program Page: http://www.dal.ca/internetworking
"We produce the Internetworking leaders of tomorrow"




More information about the nSLUG mailing list