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(ASCEND) P50 / USR problem
Anyone want to speculate about this while I wait for a reply from USR tech
support?
Some time ago I wrote with a different P50/NetServer problem involving a
USR MP bug. This has since been fixed. But watching my two ISP's deal
with USR has been educational; USR is pretty tight-lipped about what
versions exist -- possibly the fix is not an official release.
In any case, things are better but not perfect ...
~~~~~~~~~
My setup:
- 2 Macs and a PC running NT 4.0
- Ascend Pipeline 50 ISDN router with 5.0Ap5 software
- similarly configured Internet subnets at ProviderA.com and ProviderB.com
Both providers service me with USR NetServers.
ProviderA's has firmware dated 10 Apr 97.
I don't know about ProviderB's firmware
Most things work fine with both ISP's. There are a few things that do not
work properly with ProviderA's router and I'm mystified. These problems
show up with ProviderA's NetServer and do not show up with ProviderB's.
My P50 configurations are identical for the two accounts, other than the IP
addresses and routes. I'm using vanilla PPP, though I've tried MP with no
change. My MRU is 1500, though I've seen the same problems with it set to
576.
One problem is using Timbuktu Pro to control a machine in another location.
The other problem is doing FTP downloads of certain uncompressed files.
The key seems to be sequences of ASCII characters in the range 0-$1F.
I have snooped on the problem using the packet tracing facilities of the
ProviderA NetServer and my P50. The common denominator is that the
NetServer thinks it is sending an FTP TCP packet of around 500 bytes, but
the Pipeline 50 shows the packet as "RBAD" (received bad packet).
I've written a program to generate files that look like this:
(hex bytes)
1F 1F 1F 1F (512 times)
20 20 20 20 (512 times)
21 21 21 21 (512 times)
.......
FF FF FF FF (512 times)
The above file cannot be FTP'd from either ftp.ProviderA.com or from a BSD
box in California through ProviderA's NetServer and my P50. The NetServer
thinks it's sending nice packets, but the P50 is rejecting them as having
CRC errors.
I tried downloading it both with Fetch on a Mac and the NT command line FTP
on my PC. In both cases the FTP client hung while the P50 was showing bad
packets coming in.
The above file CAN be downloaded from either FTP server when I go through
ProviderB.
I changed my program to write files like this:
(hex bytes)
20 20 20 20 (512 times)
21 21 21 21 (512 times)
22 22 22 22 (512 times)
.......
FF FF FF FF (512 times)
There are no problems transferring this file from either FTP server.
I haven't observed any other manifestations of this problem -- I have no
trouble with email, web, ASCII or binary FTP uploads, and ASCII FTP
downloads. Only binary FTP downloads and Timbuktu's Control (which might
send similar byte patterns) are a problem right now.
I tried dialing into several different SPIDs at ProviderA, and got
identical results.
My best guess is that there is either a strange firmware bug in ProviderA's
NetServer or modems, or there is a NYNEX hardware problem (????? typical
programmer assignment of blame ?????) affecting only ProviderA and not
ProviderBconnect. The two ISPs are served by different NYNEX Nortel
switches. I'm on the same switch as ProviderA.
Doug
--
Doug Wyatt software development, Opcode Systems Inc.
work: doug@opcode.com http://www.opcode.com/
personal: doug@sonosphere.com http://www.sonosphere.com/doug/
music samples: http://www.sonosphere.com/doug/music.html
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