73 lines
2.8 KiB
Plaintext
73 lines
2.8 KiB
Plaintext
$Id: FAQ,v 1.4 2000/01/26 20:11:33 he Exp $
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QUESTION: How can I control the amount of debugging output?
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=========
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ANSWER:
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The eftd server now also allows to
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control the amount of debugging output via command line arguments,
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refer to the eftd(8) man page for further info.
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eftd.c and eftp.c contain a global variable tdu_stderr_mask.
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Locate this and change the comment characters (/* .. */). For only
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logging Error events, the final active statement should be
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tdu_stderr_mask = TDU_LOG_ERR | TDU_LOG_IER;
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To remove isdnlog output to stderr, you can also comment out the
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'tdu_open_isdtlog()' statement.
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QUESTION: I don't want anonymous users to dial in without a MSN
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=========
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If a client without a MSN dials in, the ISDN number 0 is assumed.
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With the line "guestservers 1* 2* 3* 4* 5* 6* 7* 8* 9*" in
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/etc/isdn/eftaccess connections with ISDN numbers beginning with
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"0" are refused. Don't forget the option "-a" for eftd to let is use
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the file /etc/isdn/eftaccess.
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(What's about international connections then? Do they begin with "0"?
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I dont'n know, never had one...)
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QUESTION: Why do I not get full 64 kBit/s transfer speed.
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=========
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First note that an isdn B channel supports 64*1000 Bit/s,
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not 64*1024 Bit/s.
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Second, note that eftp4linux is very careful not to overestimate
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the measured transfer speed (certain ftp clients don't properley
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measure data in OS-internal queues and falsly report transfer speeds
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larger than the network bandwidth for short files. Be aware of this if
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you do comparisions)
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With standard protocol configuration, data is transferred in chunks of
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around 1000 Bytes. The headers of the 3 protocol layers
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X.75/LapB (2 bytes), X.25 DTE-DTE (3 bytes), and the EUROFILE layer
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itsself (typically 6--7 bytes for large files) add slightly
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more than 1% overhead in total (which is significiently lower than
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a tcp/ip/ppp stack).
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The hdlc framing additionally adds 2 bytes for the CRC and 2 flags to
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each frame, the hdlc bit stuffing adds around 3% extra bits for
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random data. (The exact value depends on the data and might be
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between 0 and 20 %. For comparisions: as syncppp uses the same hdlc
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framing, the same overhead applies here.)
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All in all, there is an expected protocol overhead of around 4.5%,
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which should allow to transfer around 7640 bytes/s.
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Note that the current eftp4linux is not especially tuned for
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speed. It is compiled without optimization. If debugging output of
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eftp4linux isself or the drivers (e.g. by means of hisaxctrl,
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x25trace) is activated, additional computation time is required.
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If certain protocol parameters (in particular X.25 or eurofile window
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sizes of one) are in effect, transfer speed might also decrease.
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Other additional delays, such as waiting for disk or NFS IO or
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waiting for beeing scheduled on a heavily loaded system, might also
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decrease the transfer speed.
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