G'day I am not 100% sure how to explain the issue I am having, however I have 3 sites on 80Mbps fibre connections.
I am running ipsec in transport mode between the sites and EOIP tunnels on top, with OSPF routing.
Between these 80MB sites file transfers etc are all very fast.
There are some existing managed networks behind these routers at each site running in parallel at the moment until they are replaced. When I do file transfers that traverse these routers I am lucky to get 100KB/s file transfers at best.
To explain a little better, lets say we have 192.168.0.0/24, 192.168.1.0/24 and 192.168.2.0/24 at the three sites on EOIP/ipsec mikrotik to mikrotik.
Behind these sites there is 10.0.0.0/24, 10.0.1.0/24 and 10.0.2.0/24. These are all pre-existing 10Mbps connections.
File transfers between all 192.X subnets (80Mbps) are flawless. Any file transfer between the 192.x subnet and the 10.x subnet is painfully slow. As an example an 8MB file takes over 6 minutes to transfer. The average speed is approximately 100Kbps when transferring from the 10.x subnet to the 192 subnets.
The 10.x subnet is managed cisco router infrastructure, so I have no control over those routers.
I have tried adjusting the MTU for traffic between the two subnets, and also tried setting the CLEAR DF options.
If anyone could advise where I could be going wrong here that would be most appreciated.