How many connections PAT can handles?

[lifebook567]

How many connections that an IP address with PAT can support? One IP address with PAT can support 65536 hosts as there are 65536 ports available for an IP(ranging from 0 to 65535)?

[ajagadee]

Hi,

PAT (overloading) divides the available ports per global IP address into three ranges: "0-511, 512-1023, and 1024-65535". PAT assigns a unique source port for each UDP or TCP session. It will attempt to assign the same port value of the original request, but if the original source port has already been used, it will start scanning from the beginning of the particular port range to find the first available port and will assign it to the conversation.

Please refer the below URL for details:

http://www.cisco.com/en/US/products/ps6640/products_qanda_item0900aecd801ba55a.shtml

I hope it helps.

Regards,

Arul