FTP Slow From Alpha to External Sites

[Wim Van den Wyngaert]

Could you post a tcptrace/full ?
In it, the window size changes are shown.

Also post your sys$specific:[tcpip$etc]sysconfigtab.dat file.

Wim

[Robert Atkinson]

Wilm, with the Trace - do you litteraly want me to run this command, or are you looking for me to trace the packets going out to the remote FTP server?

ALPHA_ROB$$ typ sys$specific:[tcpip$etc]sysconfigtab.dat
#
# TCP/IP Services for OpenVMS V5.1
# sysconfig parameter file
#
nfs:
tcp_threads=8
udp_threads=8

vfs:
vnode_age=120

[Willem Grooters]

Petr's remark could wwll be the case - depending yout VMS/TCPIP version.
We had a similar problem, that we could drill down to two paths to a remote network (0.0.0.0) over different gateways (one the local NIC, the other the nearest router). We have the idea that starting the router would have introduces the second path but we never got proof. Deleting all routes and adding the right one solved the problem
(VMS 7.3-1, TCPIP 5.3, after clean install on new machine)

Willem

[Wim Van den Wyngaert]

Robert,

You have no special parameters set.

Before you do the slow ftp, open an extra session and start in it :
tcptrace/fu/pack=500/out=ip.txt xxx
where xxx is the ip address or name of the external site.
Then post ip.txt (with extention txt or I can't open it due to restrictions over here).

Wim

[Wim Van den Wyngaert]

Also try a traceroute to see if the same route is followed. This could be depending on segment size.

Wim

[Arch_Muthiah]

Bob,

The slow speed is posible due to CPU, the disk interface, and the overall system bandwidth in the external machine.

What type of machine/OS/Disk drives availbe in the external site. These are all consititute the reason for slow transfer rate.


Archunan

[Wim Van den Wyngaert]

Arcgu,

The system can not be in cause because ftp to an internal system has great performance.
So forget about cpu, working sets etc.

The remote system can not be blamed either because it is reacting fast when a PC is doing FTP.

IMO it must be something between the 2 nodes that is reacting differently (e.g. routers) and this only for a VMS node. So, the question is what is different in FTP-VMS compared with FTP-PC.

Robert : did you also check the tcp counters ?

Wim

[Arch_Muthiah]

Win

< The remote system can not be blamed
< either because it is reacting fast when a > PC is doing FTP.

Understand.. I am sorry.


Archunan

[Michael Yu_3]

Hi Rob,

Older versions of TCP/IP services for OpenVMS use window size of 4096 (UCX V4.2) while newer versions use window size of 61440 (TCP/IP V5.3, V5.4, etc.). FOr PC's, I think they might be using 128Kbytes window size.

Thanks and regards.

Michael

[Robert Atkinson]

The window size I saw in the trace was 4096. How can I change this in the FTP client, or do I need to do something in TCPIP$CONFIG?

Thanks for all your help BTW - I'll get the full trace done ASAP and pass back the results.

Rob.