Slow WAN Link Draytek 2820 to 2830 (both are on 10/100 leased lines....)

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Dear Experts :)
My first post, so here we go with this little doozy, any help / questions / advice is much appreciated.

I have just setup a WAN link for a customer between a DR site and their main office. The routers are passing ICMP packets fine back and forth but the file copy speed is woeful.

I’m pretty sure (but not 100%) that the config for the Lan to Lan is correct (listed below) and I have done a fair few tests to try and see where the problem(s) is /are. Both connections are leased lines that have 100Meg burst and 10Meg commit,

Both machines at either side of the WAN are windows 2003 servers

Copy time Lan to Lan of a 4Mb file   47 seconds (not really good enough as they have Gigs of stuff sometimes…)

Copy time from EITHER of the sites if I VPN (remote dial user) from them is 8 seconds (and I’m away from both sites on a bog standard Bethere ADSL)

Pings are returned in a speedy 6ms regardless of there is very low traffic (i.e. not copying anything) or if I’m trying to push any file (my 4Mb test file for instance, taking 47 seconds) up there.

Both Robocopy and standard windows copy yield the same results @ 47 seconds, all tests are done from mapped drives (be that lan to lan or whilst I’m testing with dial in VPN / Teleworker) as I have tried my best to keep an even keel when getting to the route of this little stinker.

Pinging with packet sizes up to 1472 bytes are fine across the WAN, anything larger and nothing gets returned (on the LAN there is no problem with packet size as to be expected I think :)

IP config for Wan to Wan link: (have used PPTP for the links until I’m happy then will up it to L2TP)

Router A (Draytek 2820 @ Lan IP of 192.168.1.1) (Set to allow Dial in from Router B)
Frimware Ver             3.3.5.2 (up to date @ date of this post)
Wan IP                  192.168.1.221
Remote Gateway IP      10.255.253.1
Remote Network IP      10.255.253.253
Remote Network Mask      255.255.255.0

Router B (Draytek 2830 @ Lan IP of 10.255.253.1) (Set to dial out to Router A)
Firmware Ver            3.3.6 (initial release not superseded yet)
Wan IP                   10.255.253.253
Remote Gateway IP      192.168.1.1
Remote Network IP      192.168.1.221
Remote Network Mask      255.255.255.0
Local Network IP      10.255.253.1   (this setting is new to me and not available on the 2820..)
Local Network Mask      255.255.255.0


Any thoughts experts? :)

(awarding 500 points to the expert with the solution as have spent to long on this now and its just not healthy! :)

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Steve JenningsSr Manager Cloud Networking Ops

Commented:
Get iperf and test the link by changing the tcp buffer sizes and find the optimum settung and the change the windows tcp buffer settings. Windows file copy is notoriously slow and generally not a good indicator of link speed.

If iperf shows the same result then you ha ve a different priblem.

Good luck,
Steve

Author

Commented:
Hi Steve and thanks for your suggestion and for the info on "iperf", will come in useful again.... :)

Unfortunately here isn't much difference if I put in a tcp window size of 500, 2000 or even 11111 I only get a bout 1.4mbps tops which for a 10Mbit connection I would be expecting a bit more (I appreciate the bottlenecks but 9am on a Sunday morning? :)

anything else to check?
Steve JenningsSr Manager Cloud Networking Ops

Commented:
No errors? no retransmits? can you do a trace snd post the result?  By the way, the tcp window size on a 10mbit link ought to be about 16k. And if altering the window size with iperf had no effect, thrn you have a nonnetwork problem.
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Author

Commented:
Hi Steve,

sorry for not replying earlier as have been busy with our works migration to another site.  I have run some wireshark tests and whilst on Lan to Lan there is a lot of fragmented packets, on VPN dial in its very smooth and a heck of a lot faster. For the moment I have both servers that need access to the external site remotely dialled in via VPN as a work around, while not ideal is at least getting to the customers requirements.  By trace do you meant trace route? 3 hops lan to lan. A networking specialist asked to try and change the MTU of both routers and see where thats going as its probably that, firstly he was worried that I was using IPSEC as this would make the routers cpu wirk overtime, but its not the case as its only pptp. Ill test a few more things and get back to you. - thanks
Commented:
Turns out after many times banging my head and getting someone in to have a look as well (to make sure im not mad :), and the poor chap also banging his head against the same wall it was a number of things inc: MTU's, duplex issues (Draytek was saying one thing, cisco saying another) both now set to 100Meg Full (and the draytek cold booted after that) at both ends and on both pieces of equipment (4 in total), and finally when it was not throwing any errors back but only speetest.net uploads at 8Mbps the blimmin QoS needed to be turned "off" when the menu says its "inactive" and me not looking in the right place :)

all clear! :)

Author

Commented:
all drayteks seem to ship with odd settings, upgrading the stock firmware on the 2830 even tho there is no new release is advisable as the date is wrong on it.. Thanks Draytek....

Spent a lot of time doing a lot of things to get this working so I hope it helps anyone out there doing LAN to LAN with drayteks over leased lines

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