The AltiGen Netfilter is what is responsible for assigning DiffServ/ToS and 802.1p QoS data to the voice packets from the server.

AltiGen's QA department has found that enabling the AltiGen Netfilter combined with certain NIC (Network Interface Card) settings have caused performance issues on the AltiGen servers in some heavy-load scenarios.

The easiest way to resolve this problem, if QoS tagging is not required, is to go into the NIC settings and uncheck (disable) the AltiGen Netfilter driver. If it is required to tag the voice packets with QoS values, then certain NIC settings will need to be disabled.

These settings are located in the Local Area Connection Properties, click on the Configure button and then the Advanced tab.

Change NIC settings to the following:

• IPv4 Large Send Offload--Disable
• Receive Side Scaling –Disable
• IP Security (IPSec) Offload-Disable
• TCP and IP Checksum Offload-Disabled

Please note: These items are specific to the NIC settings that exist on the Max5000. Other hardware devices will likely have similar options, however configuration of these options may vary depending on the vendor of the NIC.

Because of these problems, starting in MaxCS 6.7 and above, the AltiGen Netfilter will not be installed by default. Instead, it is available as a separate download from the AltiGen FTP site, and will be found in the same directory as the ACC / ACM download.