slow site copying / saving from file server or browsing between locations

[joaquimlopes]

Hi,

new to Meraki, hope that someone could give me some hints how to improve my current situation

copy or browsing between our different locations is too slow
if users try to save a file takes ages

site 1 link speed 1G/500M (dedicated business graded)- MX75 - MX 18.211.4
site 2 link speed 500M/500M (dedicated business graded) - MX105 - MX 18.211.4

using internet is fast or normal only the internal resources are slow

any ideas?

[CptnCrnch]

One of the easiest options here would be: how is your "Uplink Bandwidth" set up under "SD-WAN and Traffic Shaping"?

[joaquimlopes]

[Caleb-Engle]

Hi @joaquimlopes,

How much latency is there between the sites where these file transfers are being performed?

While the download/upload speeds provided by the ISP at either site certainly could be a factor, if only file transfers over VPN are affected, then it may be more likely that the bottleneck is latency. If using a TCP-based file transfer protocol, such as SMB, then an increase in latency will result in a decrease in the throughput of the file transfer.

The maximum theoretical TCP throughput can be calculated by the following formula: TCP Window size (bits) / Latency (seconds).

For example, if a server's TCP window size = 64 KB and the latency between the client and server is 50 ms, then the throughput can be calculated by: 512,000 bits / 0.050 sec = 10240000 bps ~ 10 Mbps.

To start, I'd recommend checking the latency and TCP window sizes of the affected resources and seeing whether the theoretical maximum throughput is close to the throughput clients at those sites are achieving.

[joaquimlopes]

hi again,  

any suggestions?

from the site 1

the top one is from site1 to srv on site 2

middle is from site1 to a pc on that site

last one google

trace from pc on site 1 to server on site2

Tracing route to SRxxxxx [1x.xx.x.xx]
over a maximum of 30 hops:

1 <1 ms <1 ms <1 ms 1x.xx.x.x
2 185 ms 186 ms 186 ms 4.39.213.212
3 201 ms 197 ms 199 ms 6x.xx.xx.xx
4 267 ms 265 ms 267 ms SRxxxxx [1x.xx.x.xx]

[Caleb-Engle]

Hi @joaquimlopes,

That is quite a bit of latency between these two sites which will definitely decrease the throughput of TCP-based file transfers. 

First, you should confirm whether that amount of latency is expected. If it's not, resolving this latency issue should result in a noticeable improvement in file transfers.

However, if 260+ ms of latency between these two sites is expected (ex. sites are located in different continents) then the reduced throughput should also be expected. You may be able to increase that throughput by increasing the TCP window sizes of the affected resources, however, you should not expect to get anything close to the speeds provided by the ISP.

[joaquimlopes]

Hi, 

the sites are 2km apart and only get this latency whenever i enter the meraki cloud / internal resources, any tips of what could be delaying it so much? what can i check/change  in meraki to get some useful speed and latency?

[Caleb-Engle]

Hi @joaquimlopes,

That's definitely more latency than you should expect between two sites that close together. You would still need to know more about the scope of the issue to be able to determine what exactly is causing it. For example:

• Do the two sites have a direct site-to-site VPN tunnel with each other, or do they both connect to a common hub site?
• Is all traffic between these two sites affected by this high latency? (For example, do you see the same latency when pinging site1's MX default gateway from site2?)
• Do other sites also experience similar latency when accessing resources at site2?