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Bug Reports on Cisco Web site
- Thread starter chanansan
- Start date
We had some problems with 3com nic's. Setting the switch port and the nic to fixed 100 FullDuplex solved the problem (autonegotiation never worked correctly).
Below is the bug report you were looking for.
regards,
Alain
CCNA/CCDA
CSCdt68700 Bug Details
Headline Switch reports FCS, Alignment, Runts when 3C905C connected at FD
Product cat6000 Model hw-all
Component counters Duplicate of
Severity 5 Status Closed
First Found-in Version 5.5(6) First Fixed-in Version Version help
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
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.
Below is the bug report you were looking for.
regards,
Alain
CCNA/CCDA
CSCdt68700 Bug Details
Headline Switch reports FCS, Alignment, Runts when 3C905C connected at FD
Product cat6000 Model hw-all
Component counters Duplicate of
Severity 5 Status Closed
First Found-in Version 5.5(6) First Fixed-in Version Version help
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
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.
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