Troubleshooting guide

5-19
Cisco Broadband Local Integrated Services Solution Troubleshooting Guide
OL-5169-01
Chapter 5 Troubleshooting DOCSIS Networks
Troubleshooting Slow Peformance
Note that the FTP or HTTP based upload and download test is only reliable for testing speeds of around
3Mbps or less. At higher speeds the processing power of the CPE device, Server or Network Interface
Cards may become a limiting factor in the test. For testing speeds higher than about 3Mbps, dedicated
data throughput testing equipment should be used.
In the following example, a simple FTP download and upload test is performed between a CPE device
connected to a cable modem, and an FTP server on the cable service provider's network. The cable
modem has downloaded a DOCSIS configuration file that allows a download speed of up to 256Kbps
and and upload speed of up to 64Kbps. In this test a 3 Megabyte file has been placed on the FTP server
at IP address 172.17.110.132. The user of the CPE device is given a username and password in order to
be able to log into the FTP server so that they can download this file from the FTP server, and then upload
it back to the FTP server. The command line FTP utility is used to perform the transfer. This utility is
available in virtually all versions of Microsoft Windows and Unix.
A similar test could be conducted by having an http web server set up in the service provider's network
and performing an http download.
C:\>ftp 172.17.110.132 ! Initiate the FTP session to the Server
Connected to 172.17.110.132.
220 Solaris FTP server (SunOS 5.6) ready.
User (172.17.110.132:(none)): anonymous ! Enter the FTP server username
331 Guest login ok, send your complete e-mail address as password.
Password: [e-mail] ! Enter the FTP server password.
230 User anonymous logged in.
ftp> dir ! View the contents of the current directory
200 PORT command successful.
150 ASCII data connection for /bin/ls (64.104.207.118,1282) (0 bytes).
total 74932
-rw-r--r-- 1 root other 3276800 Oct 10 19:31 cable.txt
! A 3M file that you can download.
226 ASCII Transfer complete.
ftp: 105 bytes received in 0.12 Seconds 2.46Kbytes/sec.
ftp> bi ! Turn on Binary File transfer mode
200 Type set to I.
ftp> get cable.txt ! Retrieve the file cable.txt and wait for it to download.
200 PORT command successful.
150 Binary data connection for cable.txt (192.168.1.13,3154) (3276800 bytes).
226 Binary Transfer complete.
ftp: 3276800 bytes received in 111.35Seconds 29.43Kbytes/sec.
! Download complete. It seems that the
! download occurred at 29.43Kbytes/sec
! which equals 235Kbits/sec. This is about
! 90% of the allowed 256Kbps download rate
! for the modem being tested.
ftp> put cable.txt ! Begin uploading the file. You need to make
! sure you have the correct access in order to
! upload a file to the FTP server or you may
! get an access-denied error.
200 PORT command successful.
150 Binary data connection for cable.txt (192.168.1.13,3157).
226 Transfer complete.
ftp: 3276800 bytes sent in 432.49Seconds 7.58Kbytes/sec.
! Upload Complete. Here you see the upload
! occurred at 7.58Kbytes/sec which is
! equivalent to 60.64Kbits/sec. This is
! about 90% of the allowed 64Kbps upload
! rate for the modem being tested.
ftp> quit ! Exit the FTP client application.
221 Goodbye.