Specifications

OmniAccess Reference: AOS-W System Reference
596 Part 031652-00 May 2005
z Once association and higher-layer authentication have succeeded, it is
analogous to the link light turning on in a wired Ethernet network. Trouble-
shoot the problem using traditional tools such as “ping” and “traceroute”.
Problems such as this often indicate faults in the wired network or in client
network settings. For example, the client may be configured for a static IP
address, the default gateway for the network may be down, or there may
be a routing problem.
z If the client is configured for DHCP and does not obtain an IP address, it
may indicate a problem with the DHCP server or the uplink network from
the Alcatel switch. Enable client debugging for the client device in ques-
tion. From the Alcatel CLI, use the command “aaa user debug mac <MAC
address of client>”. Log output from the debug process can be viewed by
issuing the command “show log intuser 30” (to display the last 30 lines of
the log file). DHCP activity appears in the log file.
z If multiple users on the same AP are experiencing problems, examine statis-
tics on the AP. It is possible that the network is extremely busy, is experi-
encing interference, or is experiencing a denial of service attack. Perform a
wireless packet capture when in doubt.
Client initially has network connectivity, then loses
connectivity
In this scenario, a client successfully associates to an AP, authenticates, and
has network connectivity. At some future time, communication fails.
z Ensure that a higher-layer network failure has not taken place. Use tools
such as “ping” and “traceroute” to verify. If an attempt to ping the Alcatel
switch from the client fails, the problem can be isolated to the wireless net-
work.
z If the failure took place while the user was moving, it is possible that roam-
ing failed. Examine the client’s current signal strength and data rate. If
they are low, compare the user’s physical location with the location of the
currently associated AP. This is sometimes caused by an issue known as
“client stickiness” – the tendency for a client to maintain an existing associ-
ation and ignore closer APs even when signal strength has significantly
degraded. Ideally, pre-deployment testing will identify client NICs and driv-
ers that exhibit this problem so that they can be excluded from the deploy-
ment.
z Dynamic WEP Key Exchange Failure: If the network uses 802.1x with auto-
matically-assigned WEP keys (dynamic WEP), it is possible that the key
exchange process failed. Because this key exchange is non-standard and
does not involve a verified “handshake”, the process sometimes fails with-
out an error message being generated. Resetting the client NIC or reboot-
ing the client operating system often restores connectivity in this situation.