From: Howard C. Berkowitz (hcb@gettcomm.com)
Date: Fri Jan 17 2003 - 04:05:07 GMT-3
At 8:33 AM +0800 1/17/03, Fan Shan wrote:
>?May I ask a question not very relational to CCIE.
>I am working for a IDC, one our customer complained their
>application is slow. They ask to test the ftp speed between our two
>switch port.
>BTW, our structure is connecting customers to 6509 FE port,and 100M
>bandwidth supplied.We put 2 PC to 2 port, assign different vlan for
>these 2 port,
>one to be ftp client,another to be ftp server, the test result is
>300-400Kbytes/s. We can see the mls entry established by the two ip
>address.The customer
>says the speed is too slow comparing to the port speed(100M).But
>we think this may be resulted in the tesing PCs or some features of
>FTP protocol.
If your TCP drivers don't have the high speed extensions, TCP may
very well be the problem. While the ideal speed without these
extensions (supported in many implementations is faster), it's quite
common to see a maximum effective transfer rate of about 40-50 Mbps,
or 5-6 Mbytes. Start by looking at RFC 1323 and later enhancements
such as selective acknowledgement.
It also could be the PCs or NICs.
>But I cannot explain why the speed maybe slow between two switch
>ports,but very fast to other sites on the internet
Can the same PCs do FTP faster to other Internet destinations?
>. Can someone help me to explain that?
>We are using 6509 MSFC feature,different vlans are assigned to
>different physical ports,and the routing protocol is OSPF.
.
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