Cisco in combination with Citrix provisioning

Recently I replaced the Cisco corenetwork of a customer. I replaced two Cisco 4506′s switches with two Cisco 4506′s switches. We changed two fundamental things, we replaced gbic’s with sfp’s and used IOS 15.0(2)SG instead of IOS 12.2(24)EWA5. The whole “change” went well. All tests were good, untill I tested the provisioned citrix environment.

During the boot of a provisioned citrixserver, the server kept hanging on the windows splashscreen. Not just one server, all the servers kept hanging on the splashscreen.

After hours of troubleshooting we found out that the provisioning environment was not according to the citrix provisioning best practices. After adjusting the provisioning server and the vDisk we tested again and luckely the provisioning environment worked again.

The question that remains is why provisioning worked on the switches with IOS 12.2(24)EWA5. Cisco aswell as Citrix can’t give me an answer to this question. The only thing I can think of is the statement of Cisco that says: TCP traffic has always priority over UDP traffic. This statement in combination with the provisioning settings, which were not in concord with the provisioning best practices, obviously causes this problems.

In short, when you are planning to use Cisco IOS 15.0(2) SG in combination with physical provisioned servers make sure you have the following settings:

Cisco:

switch01# configure terminal
switch01 (config)# Gigabitethernet x/x
switch01 (config-if)# description xxxx
switch01 (config-if)# switchport mode access
switch01 (config-if)# switchport access vlan x
switch01 (config-if)# spanning-tree portfast
switch01 (config-if)# speed 1xxx
switch01 (config-if)# duplex full
switch01 (config-if)# no shutdown
switch01 (config-if)# end
switch01# copy running-config startup-config 


Citrix on provisioning server:

Speed settings fixed
Duplex settings fixed
TCP Large Send Offload on disabled:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TCPIP\Parameters\Key: “DisableTaskOffload” (dword)
Value: “1″

On Target Device (vDisk):

Speed settings fixed
Duplex settings fixed
TCP Large Send Offload on disabled:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TCPIP\Parameters\Key: “DisableTaskOffload” (dword)
Value: “1″
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\BNNS\Parameters\
DWORD = EnableOffload
Value “0”

Advertisements