Very slow file transfer speed over mpls-DMVPN Tunnel

[asadgulzar90]

Hello Everyone,

I am facing slow speed issue over mpls link.

We have 8mbps Mpls line at our Head Office and remote branches have 4mbps link. Head Office and branches are connected to each other by DMVPN. I am trying to copy some files of almost 300mb size to branch computers, but it taking a lot of time, transfer rate I am getting is 40-50kb/s or some time 100-150 kb/s maximum.

Branches are connected by cisco router with FastEthernet ports.

Please guide to solve this issue.

[Giuseppe Larosa]

Hello asadgulzar90,

you have deployed a DMVPN over MPLS.

First thing I would check are the MTU settings on your DMVPN tunnel.

To avoid fragmentation that is not a good thing, your mGRE tunnel needs a reduced MTU configuration in order to take in account GRE encapsulation (24 bytes) and IPSec (if used). Using an MTU of 1400 bytes or lower is typical.

You can even help the hosts in LAN to use lower TCP MSS with

ip tcp adjust-mss 1300 on the LAN facing interfaces.

Hope to help

Giuseppe

[asadgulzar90]

Dear thanks for response, I am using below commands in my tunnel config related to mtu and tcp-mss
"ip mtu 1440"
"ip tcp adjust-mss 1360"

[balaji.bandi]

Couple of things need to test. (most of the time i have noticed end device issue for the file transfer - may be not your case )

so need to test :

1. Try extended ping from end to end (post the out come)

2. use iperf to test end to end linl confirm you have best results.

3. tell us how is these device connected ( i mean file transfer x to y, in the path what all network devices involved)

Quick test, connect directly to router one of the port and transfer and check ?