Re: How to safely remove an external SCSI device?

Cydrome Leader <presence@xxxxxxxxxxxxxx> writes:

Jeff Wieland <wieland@xxxxxxxxxxxxxxxx> wrote:
In article <gla71h$iru$2@xxxxxxxxxxxxxxxxx> Cydrome Leader <presence@xxxxxxxxxxxxxx> writes:

The only problems that I had were with some ports that were locked down
to 100/full, which causes the auto-negotiation to fail, so the Sun
winds up at 100/half. Really irritating when you're trying to net

there you go, the sun stuff doesn't work right.

From http://en.wikipedia.org/wiki/Autonegotiation

---
Parallel detection is used when a device that is capable of
autonegotiation is connected to one that is not. This happens if the
other device does not support autonegotiation or autonegotiation is
disabled via software. In this condition, the device that is capable
of autonegotiation can determine the speed of the other device, and
then choose the same speed for itself. This procedure cannot determine
the presence of full duplex, so half duplex is always assumed. A
duplex mismatch will result if the other device is in full duplex
mode, that is, one device is using full duplex while the other one is
using half duplex. The typical effect of duplex mismatch is that the
connection is working but at a very low speed.

....

Interoperability problems

The first version of the autonegotiation specification, IEEE 802.3u,
was open to different interpretations. Although most manufacturers
implemented this standard in one way, some others, including network
giant Cisco, implemented it in a different way. Autonegotiation
between devices that implemented it differently failed. This led many
network administrators to not depend on autonegotiation and instead
manually set the speed and duplex mode of each network interface
card. Even Cisco recommended its customers not to use
autonegotiation. However, the use of manually set configuration often
led to duplex mismatches, in particular when two connected devices
are:

* one manually set to half duplex and one manually set to full duplex
* one set to autonegotiation and one manually set to full duplex

Duplex mismatch problems are difficult to diagnose because the network
is apparently working, and simple programs used for network tests such
as ping report a valid connection; however, the network is much slower
than expected.

The debatable portions of the autonegotiation specifications were
eliminated by the 1998 release of 802.3. This was later followed by
the release of IEEE 802.3ab in 1999. The new standard specified that
gigabit Ethernet over copper wiring requires
autonegotiation. Currently, all network equipment
manufacturers\u2014including Cisco[1]\u2014recommend to use
autonegotiation on all access ports. On rare occasions where
autonegotiation may fail [2], it may still be necessary to force
settings.
---

Sounds like it is working as it should to me.

The only time I've seen this problem has been with (cisco) switches
with buggy firmware in switches or where autoneg has been disabled in
one end.
.

Relevant Pages

  • NIC Duplex Settings RHEL 5.2 tg3
    ... 100Mb Full Duplex. ... Advertised link modes: 10baseT/Half 10baseT/Full ... Advertised auto-negotiation: Yes ... no autonegotiation, 100baseTx-HD, link ok ...
    (RedHat)
  • Re: NIC Duplex Settings RHEL 5.2 tg3
    ... 100Mb Full Duplex. ... Advertised link modes: 10baseT/Half 10baseT/Full ... Advertised auto-negotiation: Yes ... no autonegotiation, 100baseTx-HD, link ok ...
    (RedHat)
  • Re: passing multiple params to modules via dhcpd.conf
    ... > only forcing one side, ... > switch and the tlan nic) really are performing actual autonegotiation, ... > impossible to sense duplex, only speed, the other end will fall back to ... I do have some 3c509 cards on the network which I've ...
    (comp.os.linux.networking)
  • Re: preferred way of forcing 1000BasetT, Full Duplex?
    ... The way that the ethernet standard is written is that if the other end ... does not respond to auto-negotiation then assume that it is 10BaseT at ... 10 BaseT half duplex. ... >>claims to have copious experience with mixing autonegotiation with hosts ...
    (comp.os.linux.networking)
  • Re: Very cool Ethernet speedup on OpenVMS
    ... force speed and duplex settings. ... old hardware, autonegotiation of speed and duplex ... kit has DEC-based NICs and I64 kit has Intel-based NICs but aren't ...
    (comp.os.vms)