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Unformatted text preview: ts, often between an application and the window manager. The server's 396byte reply at time 0.20 contains this property.
The next two messages from the client at times 0.30 and 0.38 form a single request to return
an atom. (Each property has a unique integer ID called an atom.) The server replies at time
0.43 with the atom.
It is impossible to delve farther into this example without providing lots of details about the
X window system, which isn't the purpose of this section. In this example a total of 12
segments comprising 1668 bytes is sent by the client and a total of 10 segments comprising
1120 bytes is sent by the server, before the window is displayed. The elapsed time was 3.17
seconds. From this point the client sent a small request every 5 seconds, averaging 44 bytes,
with an update to the window. This continued until the client was terminated.
LBX: Low Bandwidth X
The encoding used by the X protocol is optimized for LANs, where the time spent encoding file:///D|/Documents%20and%20Settings/bigini/Docu...ti/homenet2run/tcpip/tcp-ip-illustrated/other.htm (10 of 11) [12/09/2001 14.47.58] Chapter 30. Other TCP/IP Applications and decoding the data is more important than minimizing the amount of data transmitted.
While this is OK for an Ethernet, it becomes a problem for slow serial lines, such as SLIP
and PPP links (Sections 2.4 and 2.6).
Work is progressing to define a standard called Low Bandwidth X (LBX) that uses the
following techniques to reduce the amount of network traffic: caching, sending differences
from previous packets, and compression. Specifications should appear early in 1994 with a
sample implementation in the X window system Release 6. 30.6 Summary
The first two applications that we covered. Finger and Whois, are for obtaining information
on users. Finger clients query a server, often to find someone's login name (for sending them
mail) or to see if someone is currently logged in. The Whois client normally contacts the
server run by the InterNIC, looking...
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- Spring '12