This has probably been discussed in the past tho I have not seen any definitive answer for the issue.
I have a path A ----- B ------ C ------- D
speed tests from Routers A to B, B to C and A to C all run at the maximum rate that the radio link will allow, they are in fact
licensed links. The issue is the last hop. TCP Bandwidth tests between C and D run at 44 meg/Sec but when I test from B to D the speed
drops to less than 20 meg/sec and end to end tests also come in at the same speed. D is a sample connect off this router, there are ten others as router C distributes to a lot of places. We see the same effect on all ten connections.
So the question is this; Since C to D, or any other downstream location tests at 40+ meg, and the feed to the router C from the A direction is in excess of 200 Meg, why am I losing all of this speed through the router? The router is an X86 from Baltic networks running 6.5.
TCP throughput is affected by a number of factors including latency, duplex type, buffering/dropping of packets and the TCP windowing parameters themselves. I think that the reason that definitive answers don’t appear on the forum is that you really have to look at the specifics of each case to determine what is actually happening. In some cases I have looked at the “culprit” has turned out to be something quite different from the original suspect!
I agree. I was hoping to garner some suggestions and see if I have missed anything.
The links test out fine by themselves, but traffic crossing this router seems to be slowed down by something.
This router has no firewall rules or any sort and connection tracking is turned off. The output side consists of
three interfaces in a bridge and the input is not in a bridge. CPU load on this router is 3 to 5 %.
Any suggestions of things to look at are appreciated, no matter how off the wall.