No Vlan" Shown While Using A Gigabit Nic; Vlan Statistics Tool Is Not Working - Network Instruments GigaStor User Manual

"No VLAN" shown while using a Gigabit NIC

Symptoms: "No VLAN" is displayed in VLAN Statistics and/or no 802.1Q tag information is shown in your
decode. The network adapter you use to capture traffic is a Gigabit NIC.
Causes: Observer is not seeing the 802.1Q tag on packets being captured. This is sometimes caused by your
switch not sending tagged packets to Observer. See
explanation/resolution before proceeding.
Solutions: If you are using a Gigabit NIC to capture the traffic and you have checked the switch configuration,
then try using this solution. For BCM5751M NetXtreme Gigabit chips found in IBM T43, HP laptops, and Dell
Latitude laptops; there is a registry key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet can cause the driver
and chip not to strip the 802.1Q headers. To set that key, you must find the correct instance of the driver in
Windows registry and change it.
1. Open the Windows registry editor. Start > Run > Command and type regedit.
2. Search for "TxCoalescingTicks" and ensure this is the only instance that you have.
3. Right-click the instance number (e.g., 0008) and add a new string value.
4. Type PreserveVlanInfoInRxPacket and give it the value 1.
5. Restart the computer.
The Gigabit NIC no longer strips VLAN tags, so the symptom in Observer is resolved.

VLAN Statistics tool is not working

Symptoms: "No VLAN" is the only VLAN ID that shows up in the VLANs column in VLAN Statistics. You are not
seeing all VLANs you have on the network.
Causes: To display VLAN Statistics, Observer checks each packet for a VLAN tag; if no tag is present, the packet is
logged as "No VLAN." Both 802.1Q or ISL VLAN tags are stripped unless the SPAN destination port to which the
analyzer is attached has been configured to include VLAN tags.
Solutions: Configure the switch to retain the VLAN tags through the monitor port. This may be an option in the
Mirror or SPAN command on the switch, or you may have to configure the port as a trunk prior to defining it as
a SPAN port. Even if the switch is monitoring a trunk or uplink port it may strip VLAN tags unless you configure
that port to retain the tags. Refer to the documentation from your switch for details on configuring VLANs,
trunks, and analyzer ports.
If connecting the Observer analyzer to a Cisco switch, see the following link (it does require
a TAC account): http://www.cisco.com/en/US/customer/products/hw/switches/ps708/
products_tech_note09186a008015c612.shtml.
If you use a Cisco Catalyst 4500/4000, 5500/5000, or 6500/6000 Series Switch running CatOS you must configure
the destination port as a trunk port prior to configuring the SPAN port using the set trunk and set span
commands:
set trunk
module/port
[on | off | desirable | auto | nonegotiate]
[vlan_range]
set span
source_port
destination_port [rx | tx | both]
For example, to configure module 6, port 2 for monitoring an 802.1Q VLAN setup, you would enter the following
commands:
switch (enable) set trunk 6/2 nonegotiate dot1Q
switch (enable) set span 6/1 6/2
[isl | dot1q | negotiate]
VLAN Statistics tool is not working (page 87)
"No VLAN" shown while using a Gigabit NIC | 87
for