This is the Apar to fix the problem:
Abstract for VM TCP/IP APAR PQ34318
APAR PQ34318
CTC DRIVER MAY INCORRECTLY DISCARD DATAGRAMS WITH DTCCTC008E
If a datagram ends within 6 bytes of the end of the CTC write
buffer, it will be discarded by the read side and message
DTCCTC008E will be produced. Note: This problem is equivalent to
that reported by MVS CS/390 APAR PN80905.
mfG Peter Grimm
-----Urspr�ngliche Nachricht-----
Von: Scully, William [mailto:[EMAIL PROTECTED]]
Gesendet am: Mittwoch, 13. Februar 2002 17:49
An: [EMAIL PROTECTED]
Betreff: FW: TCP/IP and Linux
Thanks for the info Romney! On one of the Linux servers where I get the
error, I did an IFCONFIG and I find:
linux017:~ # ifconfig
ctc0 Link encap:Serial Line IP
inet addr:141.202.232.131 P-t-P:141.202.198.101
Mask:255.255.255.255
UP POINTOPOINT RUNNING NOARP MTU:1500 Metric:1
RX packets:7407345 errors:0 dropped:0 overruns:0 frame:0
TX packets:13113625 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:3924 Metric:1
RX packets:2629004 errors:0 dropped:0 overruns:0 frame:0
TX packets:2629004 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
I see an MTU of 1500 on ctc0. So how did such a large packet end up on the
CTC between Linux and VM?
-----Original Message-----
From: Romney White [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, February 13, 2002 11:02 AM
To: [EMAIL PROTECTED]
Subject: Re: TCP/IP and Linux
Bill:
The message is documenting the fact that Linux sent a malformed block
of packets across the CTCA. The blocks may be up to 32K (32768 bytes)
long, so a packet starting at 33134 is clearly an error. The offending
packet is at offset 31628 in the buffer.
I presume that there is a mismatch in the buffer size between Linux
and VM TCP/IP and hope there is a control you can set on the Linux
side to use a buffer size of 32K.
Romney
On Wed, 13 Feb 2002 10:55:27 -0500 Scully, William said:
>(Cross-posted to the VM and Linux on 390 lists)
>
>We find a lot of the following messages on TCP/IP's console (FL 3A0)
>regarding the CTCs for Linux servers:
>
>22:50:10 DTCCTC008E CTCA device LINUX016: UnpackReads: Inv blk hdr 33134
>from input position 31628. Last blk hdr 0. Discarding remainder of block.
>
>
>Are others of you out there seeing this? The message doesn't seem to be
>documented. What does it mean? It appears that some (but not all) servers
>loose connectivity when this happens.
>
>William P. Scully
>Systems Programmer
>Computer Associates International, Inc
>[EMAIL PROTECTED]
