@Stefan Mihajlov wrote:
@Joseph W. Doherty maybe MTU issues?
Possibly. If the source and destination aren't directly using GRE/IPSec, but it's being done by a later transit devices, source will often fill MTU and then a transit device, needs to fragment, to allow for GRE/IPSec overhead. That can slow the overall transmission rate.
As I earlier noted, there are many possibilities, but given only "Getting slow speed while sending traffic gre tunnel with ipsec", provides little context for suggesting an actual cause, and possible mitigation.
OP has an ASR tag, but we don't know the model or the transmission rate being attempted. It's possible, the "slowness" isn't even directly related to the ASR or it's totally tied to it.
Another tag for WAN, but are we doing transfers across the street or across the world? It can matter, which it is.
I had originally only mentioned IPSec/GRE causing fragmentation, being a possible issue, as it's often encountered with tunnels that cannot extend the MTU.
