Cisco Cisco 2000 Series Wireless LAN Controller
7
Release Notes for Cisco Wireless LAN Controllers and Lightweight Access Points for Release 3.2.195.10
OL-12930-01
Important Notes
Multicast Group Address Not Supported on 2006 Controllers
If you choose Multicast from the Ethernet Multicast Mode drop-down box on the Controller > General
page, a Multicast Group Address edit box appears to the right of the drop-down box. However, this edit
box should not appear for 2006 controllers because they do not support a Multicast Group Address.
page, a Multicast Group Address edit box appears to the right of the drop-down box. However, this edit
box should not appear for 2006 controllers because they do not support a Multicast Group Address.
Service Modules Supported in the Catalyst 6500 Series Switch
The Catalyst 6500 Series Switch chassis can support up to five Cisco WiSMs without any other service
module installed. If one or more service modules are installed, the chassis can support up to a maximum
of four service modules (WiSMs included).
module installed. If one or more service modules are installed, the chassis can support up to a maximum
of four service modules (WiSMs included).
DHCP Servers Must Have Duplicate IP Checking Enabled
For the Cisco WiSM, you need to enable duplicate IP detection on your DHCP servers. Otherwise,
multiple clients may be assigned the same IP addresses.
multiple clients may be assigned the same IP addresses.
RADIUS Server Failover Behavior
If you enter the config radius aggressive-failover enable command, the RADIUS server switches over
to the backup server if it fails to answer one RADIUS request after five retransmissions. This is the
default behavior. If you enter the config radius aggressive-failover disable command, the RADIUS
server switches over to the backup server only if it fails to answer three consecutive RADIUS requests
(where each RADIUS request is retransmitted five times).
to the backup server if it fails to answer one RADIUS request after five retransmissions. This is the
default behavior. If you enter the config radius aggressive-failover disable command, the RADIUS
server switches over to the backup server only if it fails to answer three consecutive RADIUS requests
(where each RADIUS request is retransmitted five times).
Access Points Fail to Join Controllers If MTU Setting Is Less Than 1500
When the network path between access points and the controller is configured for an MTU size less than
1500, the controller does not receive join requests from access points in local mode. (MTU settings less
than 1500 are common when you use tunneling protocols such as IPsec VPN, GRE, and MPLS.) The
access point join request is larger than 1500 bytes, so the request is fragmented. The size of the first
fragment is 1500 bytes (including IP and UDP header) and the second fragment is 54 bytes (including
IP and UDP header).
1500, the controller does not receive join requests from access points in local mode. (MTU settings less
than 1500 are common when you use tunneling protocols such as IPsec VPN, GRE, and MPLS.) The
access point join request is larger than 1500 bytes, so the request is fragmented. The size of the first
fragment is 1500 bytes (including IP and UDP header) and the second fragment is 54 bytes (including
IP and UDP header).
Access points in REAP mode are not affected by this limitation, and the problem is resolved in the 4.0
software release because the LWAPP tunnel can reassemble up to four fragments. The problem occurs
when all four of these conditions exist on your network:
software release because the LWAPP tunnel can reassemble up to four fragments. The problem occurs
when all four of these conditions exist on your network:
•
Your controller runs software release 3.2 or earlier
•
Your controller is configured for Layer 3 LWAPP
•
The network path MTU between the access point and the controller is less than 1500 bytes
•
The access point is in local access point (LAP) mode (not REAP mode)