TCP Overhead

[radsin]

Hi..
I checked my download and upload traffic by "analogx NetStat"tool..but when i got the traffic bill from my isp there is a lot of deviation..i was told by my ISP Service team because i've not calucaulated the overhead that diff came..
Can anybody tell me what is it..
Thanks

Srikrishna

[Stef]

The overhead that your ISP is talking about is related to the information that passes on the Data-Link layer of the OSI model.

Every networking topology has it own method of access control. MAC (Media Access Control) and LLC (Link-Layer Control) are needed to regulate the transmission of data frames on a network. Each networking topology uses its own method of access control, an example would be token passing (used in token ring) compared to CSMA/CD (used in ethernet)

These access control methods are not by any means perfect. They actually can add overhead in the overall transmission process since a frame must go through the access control process before initiating an actual conversation with another node on a network.

Stef