Filter
Top Products
76
There are two types of data connections: active connection and passive connection.
In active connection, the client transmits its address and port number for data
transmission to the sever, the management connection maintains until data transfer is
complete. Then, using the address and port number provided by the client, the server
establishes data connection on port 20 (if not engaged) to transfer data; if port 20 is
engaged, the server automatically generates some other port number to establish data
connection.
In passive connection, the client, through management connection, notify the server
to establish a passive connection. The server then create its own data listening port and
inform the client about the port, and the client establishes data connection to the specified
port.
As data connection is established through the specified address and port, there is a
third party to provide data connection service.
TFTP builds upon UDP, providing unreliable data stream transfer service with no user
authentication or permission-based file access authorization. It ensures correct data
transmission by sending and acknowledging mechanism and retransmission of time-out
packets. The advantage of TFTP over FTP is that it is a simple and low overhead file
transfer service.
ES4626/ES4650 can operate as either FTP/TFTP client or server. When
ES4626/ES4650 operates as a FTP/TFTP client, configuration files or system files can be
downloaded from the remote FTP/TFTP servers(can be hosts or other switches) without
affecting its normal operation. And file list can also be retrieved from the server in ftp client
mode. Of course, ES4626/ES4650 can also upload current configuration files or system
files to the remote FTP/TFTP servers(can be hosts or other switches). When
ES4626/ES4650 operates as a FTP/TFTP server, it can provide file upload and download
service for authorized FTP/TFTP clients, as file list service as FTP server.
Here are some terms frequently used in FTP/TFTP.
ROM: Short for EPROM, erasable read-only memory. EPROM is repalced by FLASH
memory in ES4626/ES4650.
SDRAM: RAM memory in the switch, used for system software operation and
configuration sequence storage.
FLASH: Flash memory used to save system file and configuration file
System file: including system mirror file and boot file.
System mirror file: refers to the compressed file for switch hardware driver and software
support program, usually refer to as IMG upgrade file. In ES4626/ES4650, the system
mirror file is allowed to save in FLASH only. ES4626/ES4650 mandates the name of
system mirror file to be uploaded via FTP in Global Mode to be nos.img, other IMG system
files will be rejected.
Boot file: refers to the file initializes the switch, also referred to as the ROM upgrade file
(Large size file can be compressed as IMG file). In ES4626/ES4650, the boot file is