John Neiberger wrote:
>
> We've had nothing but bad luck with the 3C905C NICs. We've purchased a
> *bunch* of low-end Dell PCs that have that NIC and they tend to get the
> blue screen of death and then reboot if they're connected to Cisco
> switches, especially when STP is turned on. Very odd behavior and we
> haven't found a solution yet. We'd better come up with something fast
> because we're getting more of those pieces of junk soon.
>
Here's an old Cat 5000 bug report that I saved:
BugID: CSCdt68700
Title: Switch reports FCS, Alignment, Runts when 3C905C connected at
FD
Feature: counters
Version: 5.5(6)
Integrated:
Severity: 5
State: C
Release Notes:
Under normal traffic conditions, a 100 Megabit, Full-duplex connection
between
any Cisco Catalyst Switch and a 3Com 3C905C will result in Layer 2 errors.
The
Catalyst Switch will report these Layer 2 errors as FCS, Alignment and Runt
Packets.
Troubleshoot this issue by reviewing the below guidelines and documentation.
1. Verify that both the 3Com 3C905C and Catalyst Switch are both set for
auto-negotiate or both are manually set for 100 MB, Full-Duplex. A duplex
mismatch will cause a higher rate of Layer 2 (physical) layer errored frames.
2. Load the lastest 3Com 3C905C driver available from www.3com.com
3. Load the diagnostic utility available with the lastest 3Com 3C905C
driver.
update.exe /diag)
4. Connect 2 test workstations with 3Com 3C905Cs back-to-back using a
crossover
cable.
5. Test Connectivity initiating a large file transfer between the
workstations
and noting the following counters with the 3Com Diag Utility. This test, the
back-to-back between the PCs with 3C905C(s), will give a benchmark for
performance and physical layer errors.
According to the 3Com documentation, the details of the following counters
are
significant:
Receive Overruns: Receive Overrun is the number of lost packets that cannot
be
stored in the receive buffer because the PC''s buffer is already full.
Carrier Sense Lost: Carrier Sense Lost is the number of packets transmitted
with a carrier sense loss. This normally occurs as a result of collisions.
Transmit Underrun: Transmit underrun is the number of times a packets was
transmitted without adequate data by the NIC.
In respective the Catalyst Switch Counters, a packet transferred that
results in
the Carrier Sense Lost or Transmit Underrun incrementing on the 3Com NIC
will
cause at least one of the following counters to increase on the Switch:
Alignment, FCS, CRC, Input Errors, Receive Errors, and/or Runts.
Noting the errors and performance back-to-back between 2 PCs with the 3C905C
NIC will give a minimum baseline for the number of errors reported by the
switch
and a generally baseline for performance.
6. Repeat step 5 with the PCs connected to the switch and baseline the
number
of errors to the errors recorded in Step 5. Expect a higher number of
errors
when the workstation is connected to the network as there will be higher
load of
traffic including multicast, unicast-flood, and broadcast traffic.
Note: It has been noted that increasing CPU/BUS Speed on the workstation
increases the number of Transmit Underrun packets recorded on the NIC and
Runt
Packets on the Catalyst Switches.
In conclusion, this issue is not a Switch specific issue nor an issue with
compatability. Please contact 3Com Tech Support for resolution.
- Marty
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7&i=51543&t=51419
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