Concept Questions
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Why did you create another client?
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Does "FTP" refer to the protocol, the client, or the server?
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What is GridFTP?
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Then what is GSI FTP?
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What is the relationship between GSIFTP and GridFTP?
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Concept Answers
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Why did you create another client?
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At the time of creation, no other interactive GridFTP clients
were available, or none were known to be available.
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Does "FTP" refer to the protocol, the client, or the server?
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FTP refers to the protocol. The client and server are implementations of
that protocol.
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What is GridFTP?
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GridFTP is an unofficial addition to the FTP protocol. In adds
needed features like parallel data connections, striping
across servers and data channel authentication.
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Then what is GSI FTP?
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GSI FTP is the FTP protocol, standard or extended with GridFTP, that uses
GSI authentication. GSI is a form of PKI (public/private keys with
certificates). GSI FTP uses certificates instead of clear text
username/password combinations. GSI is added to the protocol
by making use of RFC 2228.
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What is the relationship between GSIFTP and GridFTP?
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Globus introduced GSI FTP with Globus 1.x. It included a standard FTP client (gsincftp)
and server. The only modification was to add GSI authentication to the client and server
as defined in RFC 2228. In 2.x, Globus included a GridFTP client (globus-url-copy) and
server. The modifications included parallel data channels, striping, etc. The GridFTP
protocol does not explicitly imply GSI authentication, it does however build on top of
RFC 2228 features to provide data channel authentication (DCAU).
So, GridFTP does not obsolete GSI FTP, it builds upon it. You could have GridFTP services
using Kerberos (also supported via RFC 2228). Or you could have GridFTP without DCAU
using a non RFC 2228 authentication mechanism such as username and password or hardware
authentication. However, most people only recognize the GridFTP buzzword and since GSI
was quickly adopted as the Grid authentication mechanism, the two terms are synonymous
for most end users.
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