Public bug reported:
Binary package hint: network-manager-pptp
I'm using a fresh install of Intrepid 64bit on a machine with 4GB of
memory. I've got a PPTP tunnel running back to work. I quickly noticed
that performance was very poor over this link. There are a lot of
stalls; web pages take a very long time to render and SSH connections
stall a lot. I may be a bit presumptuous in assuming this is a bug - but
this issue is not present with Hardy 32bit. While diagnosing the issue I
noticed a lot of packet buffering mesages in the syslog:
Nov 2 08:42:41 john00-desktop2 pptp[8338]: nm-pptp-service-8329
log[decaps_gre:pptp_gre.c:414]: buffering packet 1576 (expecting 1575, lost or
reordered)
Nov 2 08:42:41 john00-desktop2 pptp[8338]: nm-pptp-service-8329
log[decaps_gre:pptp_gre.c:414]: buffering packet 1577 (expecting 1575, lost or
reordered)
Nov 2 08:42:41 john00-desktop2 pptp[8338]: nm-pptp-service-8329
log[decaps_gre:pptp_gre.c:414]: buffering packet 1584 (expecting 1583, lost or
reordered)
Nov 2 08:42:41 john00-desktop2 pptp[8338]: nm-pptp-service-8329
log[decaps_gre:pptp_gre.c:414]: buffering packet 1585 (expecting 1583, lost or
reordered)
Nov 2 08:42:42 john00-desktop2 pptp[8338]: nm-pptp-service-8329
log[decaps_gre:pptp_gre.c:414]: buffering packet 1589 (expecting 1588, lost or
reordered)
Nov 2 08:42:42 john00-desktop2 pptp[8338]: nm-pptp-service-8329
log[decaps_gre:pptp_gre.c:414]: buffering packet 1590 (expecting 1588, lost or
reordered)
Nov 2 08:42:42 john00-desktop2 pptp[8338]: nm-pptp-service-8329
log[decaps_gre:pptp_gre.c:414]: buffering packet 1593 (expecting 1592, lost or
reordered)
My Wireshark packet captures show a lot of retransmissions and duplicate
ACK's which appear to be the cause of the performance problems:
18 39.050106 172.29.14.101 172.29.17.192 TCP [TCP Previous
segment lost] [TCP segment of a reassembled PDU]
19 39.050145 172.29.17.192 172.29.14.101 TCP [TCP Dup ACK
15#1] 45754 > http [ACK] Seq=438 Ack=4333 Win=14592 Len=0 TSV=2398754
TSER=75797622 SLE=5777 SRE=6961
29 39.425900 172.29.14.101 172.29.17.192 TCP http > 45756
[ACK] Seq=1 Ack=453 Win=50540 Len=0 TSV=75797662 TSER=2398760
30 39.747035 172.29.14.101 172.29.17.192 TCP [TCP Previous
segment lost] [TCP segment of a reassembled PDU]
31 39.747055 172.29.17.192 172.29.14.101 TCP [TCP Dup ACK
25#1] 45756 > http [ACK] Seq=453 Ack=1 Win=5888 Len=0 TSV=2398928 TSER=75797662
SLE=1445 SRE=1705
32 39.834203 172.29.14.101 172.29.17.192 HTTP [TCP
Retransmission] HTTP/1.1 200 OK (text/html)
I'm not sure how to go about further diagnosing this issue. Perhaps it's
related to other known issues with Network Manager. This is a test
machine so I'm not afraid to break it.
Thank you,
John
** Affects: network-manager-pptp (Ubuntu)
Importance: Undecided
Status: New
** Description changed:
Binary package hint: network-manager-pptp
I'm using a fresh install of Intrepid 64bit on a machine with 4GB of
memory. I've got a PPTP tunnel running back to work. I quickly noticed
that performance was very poor over this link. There are a lot of
stalls; web pages take a very long time to render and SSH connections
stall a lot. I may be a bit presumptuous in assuming this is a bug - but
- this issue present with Hardy 32bit. While diagnosing the issue I
+ this issue is not present with Hardy 32bit. While diagnosing the issue I
noticed a lot of packet buffering mesages in the syslog:
Nov 2 08:42:41 john00-desktop2 pptp[8338]: nm-pptp-service-8329
log[decaps_gre:pptp_gre.c:414]: buffering packet 1576 (expecting 1575, lost or
reordered)
Nov 2 08:42:41 john00-desktop2 pptp[8338]: nm-pptp-service-8329
log[decaps_gre:pptp_gre.c:414]: buffering packet 1577 (expecting 1575, lost or
reordered)
Nov 2 08:42:41 john00-desktop2 pptp[8338]: nm-pptp-service-8329
log[decaps_gre:pptp_gre.c:414]: buffering packet 1584 (expecting 1583, lost or
reordered)
Nov 2 08:42:41 john00-desktop2 pptp[8338]: nm-pptp-service-8329
log[decaps_gre:pptp_gre.c:414]: buffering packet 1585 (expecting 1583, lost or
reordered)
Nov 2 08:42:42 john00-desktop2 pptp[8338]: nm-pptp-service-8329
log[decaps_gre:pptp_gre.c:414]: buffering packet 1589 (expecting 1588, lost or
reordered)
Nov 2 08:42:42 john00-desktop2 pptp[8338]: nm-pptp-service-8329
log[decaps_gre:pptp_gre.c:414]: buffering packet 1590 (expecting 1588, lost or
reordered)
Nov 2 08:42:42 john00-desktop2 pptp[8338]: nm-pptp-service-8329
log[decaps_gre:pptp_gre.c:414]: buffering packet 1593 (expecting 1592, lost or
reordered)
My Wireshark packet captures show a lot of retransmissions and duplicate
ACK's which appear to be the cause of the performance problems:
18 39.050106 172.29.14.101 172.29.17.192 TCP [TCP Previous
segment lost] [TCP segment of a reassembled PDU]
19 39.050145 172.29.17.192 172.29.14.101 TCP [TCP Dup ACK
15#1] 45754 > http [ACK] Seq=438 Ack=4333 Win=14592 Len=0 TSV=2398754
TSER=75797622 SLE=5777 SRE=6961
29 39.425900 172.29.14.101 172.29.17.192 TCP http > 45756
[ACK] Seq=1 Ack=453 Win=50540 Len=0 TSV=75797662 TSER=2398760
30 39.747035 172.29.14.101 172.29.17.192 TCP [TCP Previous
segment lost] [TCP segment of a reassembled PDU]
31 39.747055 172.29.17.192 172.29.14.101 TCP [TCP Dup ACK
25#1] 45756 > http [ACK] Seq=453 Ack=1 Win=5888 Len=0 TSV=2398928 TSER=75797662
SLE=1445 SRE=1705
32 39.834203 172.29.14.101 172.29.17.192 HTTP [TCP
Retransmission] HTTP/1.1 200 OK (text/html)
I'm not sure how to go about further diagnosing this issue. Perhaps it's
- related to other known issues with Network Manager.
+ related to other known issues with Network Manager. This is a test
+ machine so I'm not afraid to break it.
Thank you,
John
--
Intrepid Slow PPTP Performance - retransmits and lost ACKs
https://bugs.launchpad.net/bugs/292799
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