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VPN Speed, slower than dial up, how can i calculate what i should be able to get

Hi all,

I just checked the speed of 4 site to site tunnels our company has, then i checked the speed we should be getting from our ISP at each site

Site1 - Site2 | 2mb file transferred on average at 32kbps
Site1 - Site3 | 2mb file transferred on average at 18kbps
Site1 - Site4 | 2mb file transferred on average at 32kbps
Site2 - Site3 | 2mb file transferred on average at 32kbps

From ISP Download speeds:

Site 1 gets 16mbps
Site 2 gets 16mbps
Site 3 gets 16mbps
Site 4 gets 5mbps

dont know about upload speeds which i know will effect it, but they dont post uploads but i grabbed this info

Connection speeds are affected by line length, quality and peak internet usage periods and will range from 256kbps to a maximum of 18000kbps. Upload speeds will range from 256kbps to a maximum of 1000kbps

Site 1 uses a cisco 837 into a linksys vpn router, but with what i have learnt i plan on removing the linksys and placing the 837 in charge of the tunnels
Site 2 uses a cisco 837 that i set up the vpn on
Site 3 uses a draytek Vigor 2820
site 4 uses a spedtouch peice of crap that i cant log into, and a linksys vpn router i will replace this eventually

but can anyone maybe explain to me what should be happening, what i should expect and what to do about it?

i have also run a packet capture on through wire shark and have attached a screenshot of the output
i dont undertand what it means but it looks like there are errors? can anyone expain how to read this to me too?

Thanks alot for your help i know this will be a tough one!
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1 Solution

You're probably using some kind of ADSL ? Your max. upload speed will greatly affect the transfer speed over the VPN, probably to 256kps if you have no other traffic at all.

Also I notice that you're measuring speed by copying files from Windows shares (SMB protocol). SMB is a very,very inefficient protocol to use over VPN/WAN connections because latency will slow things down to a crawl.

Try measing latency using ping and post the results here. Als try transfering files using ftp, this will probably be a bit faster.
awilderbeastAuthor Commented:
ok ive put Filezilla ftp server on one end and filezilla ftp client at my end

now i get 60-80kbps closer to 80kb most of the time, doubled the speed there
is this an acceptable speed for my connection?

i run a vpn capture on the transfter too (image below

what are these errors they normal?

i know smb is slower but staff use windows explorer to view and access files on different servers

which uses smb? what else can i provide as a solution for staff to access files on different servers that doesnt take 5-10 mins to open a word doc :|

thanks for your help so far

1. the checksum errors are probably wireshark related and can be ignored:


2. 80kbps is probably the max. you can get because your upstream is limited. Getting more upstream bandwidth will help somewhat, but if latency is high this doesn't help with SMB.

3. SMB/CIFS (=all Microsoft based file sharing) is not suitable for WAN. I know of 3 possible solutions:

- use a WAN accelerator (e.g. riverbed, cisco, ...) but these are very expensive.
- use Citrix or Windows Terminal server to let your remote users access your central resources using a ICA/RDP session.
- using Windows server 2008 + Windows vista only clients, you can use a more efficient version of SMB/CIFS that should work a bit better. We don't have experience with this, though.

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awilderbeastAuthor Commented:
ah right thanks for the wireshark info :)

my isp says that the upload limit is up to 1mbps surely it should be better than 80kb?

what do normal business using for file sharing over vpn then?
we have 4 servers in 4 offices each with files on that other offices like to access
what can i do?

i dont understand why the vpn would be soo slow... :S


>my isp says that the upload limit is up to 1mbps surely it should be better than 80kb?

To make sure we're on the same page here:

You do know that 1 Mbps = 125KB/s ? I mean, when you measure speed you're talking about 80Kbit/s, not 80KByte/s ?

awilderbeastAuthor Commented:
1mbp is 1024 kb no?

1Mbps = 1024Kbit/s = 128Kbyte/sec = 0,128 MByte/sec
awilderbeastAuthor Commented:
oh righ ti see, well where talking kilobits then it takes 1:30 to transfer a 2mb file to another server, but i can upload the samle file to the web in about 30 seconds

ok, that seems about normal for a 1Mbit/s line, given that there's always some other traffic.

As said before, CIFS/SMB is unsuitable for use on a WAN. See possible solutions above.

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