Date: Wed, 21 Jul 1999 17:42:34 +0200 From: Udo Schweigert <ust@cert.siemens.de> To: Markus Kurek <kurek@unidui.uni-duisburg.de> Cc: freebsd-isdn@FreeBSD.ORG Subject: Re: sppp VJ compression under NetBSD Message-ID: <19990721174234.A3719@alaska.cert.siemens.de> In-Reply-To: <3794F17C.95EAE58B@uni-duisburg.de>; from Markus Kurek on Tue, Jul 20, 1999 at 09:00:28PM %2B0000 References: <3794F17C.95EAE58B@uni-duisburg.de>
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On Tue, Jul 20, 1999 at 09:00:28PM +0000, Markus Kurek wrote:
> Hi,
>
> I reported a problem compiling the newest i4b beta release with
> NetBSD-1.4 a few days ago.
>
> Udo Schweigert suggested a change to spppcontrol.c. This allows me
> to compile this beast :)
> Unfortunately spppcontrol did not work as expected with a new kernel.
>
> The problem is that the kernel is built with its own
> copy of if_spppsubr.c found in /usr/src/sys-i4b/net.
> So I changed in conf/files
>
> file net/if_spppsubr.c sppp
> to
> file i4b/sppp/if_spppsubr.c sppp
>
> Now spppcontrol worked but unfortunately I could not establish
> a sppp line to my provider. spppcontrol reported that the phase is
> established but it never gets to phase=network.
> A try to dial in crashed the system immediately.
>
> As a last try I reverted the change to conf/files and moved
> the files if_spppsubr.c and if_sppp.h from the i4b-package to net/
>
> And to my surprise it works now.
>
> But new questions arise :)
>
> 1. It seems that all kernel from older i4b-releases used the wrong
> if_spppsubr.c on NetBSD. This was not a problem until the recent
> change to sppp. The installscript creates a link to the correct
> version in the i4b tree, but the file is never used!
> Perhaps the installscript should be changed so the 2 files
> are copied to net/. But I don't know if this breaks
> anything else. A quick grep on the kernel-sources showed
> that only a few files in dev/pci include net/if_sppp.h.
>
Sorry, but since I'm not using NetBSD I can't do anything on this subject,
maybe Martin Husemann can help ;-)
>
> 2. What is the benefit of the VJ compression ?
> Does it compress user data similar to the v42bis compression
> on analog modems ?
> I know windows9x and NT provides "software compression" to
> ppp-connections. If enabled this boosts downloads of uncompressed text
> very good (> 14KB/sec is not unfamiliar).
> I tried downloading a text file but I could not see a benefit of
> some kind of compression (still around 7KB/sec).
>
VJ compression does only compress the TCP headers (not the data), so you
get the 7KB/sec.
> Is there a way to see if compression is enabled or not?
> dmesg gives me this:
> i4bipr: 2 IP over raw HDLC ISDN device(s) attached (VJ header
> compression)
> i4bisppp: 4 ISDN SyncPPP device(s) attached
>
If you ifconfig your device with the debug option you will see something like
this:
Jul 21 17:06:29 diehard /kernel: isp0: ipcp open(initial)
Jul 21 17:06:29 diehard /kernel: isp0: ipcp up(starting)
Jul 21 17:06:30 diehard /kernel: isp0: ipcp output <conf-req id=0x3 len=16 02-06-00-2d-0f-01-03-06-00-00-00-00>
Jul 21 17:06:30 diehard /kernel: isp0: ipcp input(req-sent): <conf-req id=0x1 len=16 02-06-00-2d-0f-01-03-06-95-ca-df-02>
Jul 21 17:06:30 diehard /kernel: isp0: ipcp parse opts: compression address
Jul 21 17:06:30 diehard /kernel: isp0: ipcp parse opt values: compression VJ [ack] address 0.0.0.1 [ack] send conf-ack
^^^^^^^^^^^^^^^^
!!!!!!!!!!!!!!!!
Jul 21 17:06:30 diehard /kernel: isp0: ipcp output <conf-ack id=0x1 len=16 02-06-00-2d-0f-01-03-06-95-ca-df-02>
Regards
Udo
-------------------------------------------------------------------------------
Udo Schweigert || Voice : +49 89 636 42170
Siemens AG, Siemens CERT || Fax : +49 89 636 48000
ZT IK 3 || email : Udo.Schweigert@mchp.siemens.de
D-81730 Muenchen / Germany || : ust@cert.siemens.de
PGP fingerprint || 2A 53 F6 A6 30 59 64 02 6B C4 E0 73 B2 C9 6C E7
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