Networking Question Regarding Gigbit Ethernet

Michael Butash michael at butash.net
Sun Jul 1 14:53:07 MST 2012


Unless you have a managed switch, don't force negotiation, as it'll just 
cause the switch to run in 10base/half-duplex (lowest common 
denominator) when there is no negotiation advertised.  It's sitting in 
100/full already, which is what you want.

If you do ifconfig eth0, do you see any errors?  Collisions and CRC 
errors will stack if there is a negotiation problem.  Seems like either 
the switch or phy port on the mybook is wack, but doesn't make a lot of 
sense you'd lose that much anyways.  Try different switch port/cable if 
there are errors.

Have you tried pinging from the mbl itself to the gateway or other 
hosts?  Could be they have some kind of input iptables filter 
rate-limiting/shaping packets or some such, but unlikely.

-mb


On 07/01/2012 02:39 PM, Mark Phillips wrote:
> I was able to ssh into the MBL and it has ethtool installed -
>
> MyBookLive:~# ethtool eth0
> Settings for eth0:
>      Supported ports: [ MII ]
>      Supported link modes:   10baseT/Full
>                              100baseT/Full
>                              1000baseT/Full
>      Supports auto-negotiation: Yes
>      Advertised link modes:  10baseT/Full
>                              100baseT/Full
>                              1000baseT/Full
>      Advertised auto-negotiation: Yes
>      Speed: 100Mb/s
>      Duplex: Full
>      Port: MII
>      PHYAD: 1
>      Transceiver: external
>      Auto-negotiation: on
>      Link detected: yes
> MyBookLive:~#
>
> So, it should work on 100baeT. Any thoughts on why I am loosing so many
> packets?
>
> Mark
>
> On Sun, Jul 1, 2012 at 2:09 PM, Mark Phillips
> <mark at phillipsmarketing.biz <mailto:mark at phillipsmarketing.biz>> wrote:
>
>     So I need to run this on the MLB?
>
>     Mark
>
>     On Jul 1, 2012 1:36 PM, "James Mcphee" <jmcphe at gmail.com
>     <mailto:jmcphe at gmail.com>> wrote:
>
>         As such.  You need to use whatever eth device you have, of course.
>
>         jmcphee at locus ~ :) $ sudo ethtool eth2
>         Settings for eth2:
>                  Supported ports: [ TP MII ]
>                  Supported link modes:   10baseT/Half 10baseT/Full
>                                          100baseT/Half 100baseT/Full
>                                          1000baseT/Half 1000baseT/Full
>                  Supported pause frame use: No
>                  Supports auto-negotiation: Yes
>                  Advertised link modes:  10baseT/Half 10baseT/Full
>                                          100baseT/Half 100baseT/Full
>                                          1000baseT/Half 1000baseT/Full
>                  Advertised pause frame use: Symmetric Receive-only
>                  Advertised auto-negotiation: Yes
>                  Link partner advertised link modes:  10baseT/Half
>         10baseT/Full
>                                                       100baseT/Half
>         100baseT/Full
>                  Link partner advertised pause frame use: Symmetric
>                  Link partner advertised auto-negotiation: Yes
>                  Speed: 100Mb/s
>                  Duplex: Full
>                  Port: MII
>                  PHYAD: 0
>                  Transceiver: internal
>                  Auto-negotiation: on
>                  Supports Wake-on: pumbg
>                  Wake-on: g
>                  Current message level: 0x00000033 (51)
>                                         drv probe ifdown ifup
>                  Link detected: yes
>
>
>         On Sun, Jul 1, 2012 at 1:22 PM, Mark Phillips
>         <mark at phillipsmarketing.biz <mailto:mark at phillipsmarketing.biz>>
>         wrote:
>
>             How do I use ethtool to answer your question?
>
>             Mark
>
>
>             On Sun, Jul 1, 2012 at 12:52 PM, James Mcphee
>             <jmcphe at gmail.com <mailto:jmcphe at gmail.com>> wrote:
>
>                 What does ethtool tell you about what the interface
>                 thinks it is?
>
>                 On Sun, Jul 1, 2012 at 12:44 PM, Mark Phillips
>                 <mark at phillipsmarketing.biz
>                 <mailto:mark at phillipsmarketing.biz>> wrote:
>
>                     I have a 100baseT network with several Debian
>                     servers, a mac book, and some virtual windows. I
>                     just picked up a Western Digital My Book Live (MBL)
>                     2TB NAS at Costco, and powered it up on my network.
>                     The unit is just sitting with its green light on,
>                     and the web interface is really slow. When I ping
>                     the device, it shows somewhere from 50% to 86%
>                     packet loss. If I ping any other computer on the
>                     network I have 0% packet loss. I have tried moving
>                     the device to different physical plugs, and I get
>                     the same results.
>
>                     ping results for the MBL from server A:
>                     --- 192.168.25.213 ping statistics ---
>                     330 packets transmitted, 152 received, 53% packet
>                     loss, time 329555ms
>                     rtt min/avg/max/mdev = 0.208/0.273/0.650/0.048 ms
>
>                     --- 192.168.25.213 ping statistics from server B ---
>                     254 packets transmitted, 120 received, 52% packet
>                     loss, time 252998ms
>                     rtt min/avg/max/mdev = 0.196/0.264/2.499/0.206 ms
>
>
>                     ping results for  server A to B:
>                     --- 192.168.25.130 ping statistics ---
>                     340 packets transmitted, 340 received, 0% packet
>                     loss, time 338996ms
>                     rtt min/avg/max/mdev = 0.080/0.177/0.246/0.030 ms
>
>                     The device says gigabit Ethernet next to the
>                     Ethernet port. Is there any reason I can't connect a
>                     gigabit Ethernet device to a 100baseT network other
>                     than the obvious speed difference? Should I see all
>                     this packet loss? This is actually the second unit I
>                     have tried - the first one acted the same way, so I
>                     took it back. I am now wondering if I am doing
>                     something wrong.
>
>
>                     Thanks!
>
>                     Mark
>
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>                 --
>                 James McPhee
>                 jmcphe at gmail.com <mailto:jmcphe at gmail.com>
>
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