How Should IP Packet Fragmentation Be Tackled ?
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NLB has problems in dealing with fragmented IP packets; thus, fragmentation must be avoided.
Especially in cases where part of the connections between phones and DLS is transmitted through VPN channels,fragmentation may appear easily. This can be avoided by creating room for additional bytes in the VPN channel.
For this purpose. the TCP parameter "MSS" (Maximum Segment Size; maximum TCP payload) must be set to a value below the TCP maximum of 1460.
Using Cisco® Equipment you should activate the "MSS adjust" feature.
Example: ip tcp adjust-mss 1300
