WR44 - L2TP over 4G with PPP authentication (not IPSec): Throughput Query

Question

With the Digi WR44v2, we run L2TP with PPP autentication over 4G, into our privale MPLS (not with IPSec), and we see a significant drop in spped compared to a direct connection to the provider network (EE). Typical 44Mbs download through L2TP, compared to 80Mbs download to EE. We also see a drop in speed using GRE.

Tests are to www.speedtest.net using WR44v2 (WR44-L100-NE1-SW) FW ver. 5.2.15.6

Extensive testing shows no problems (congestion or otherwise) through our MPLS, we are querying whether additional processor overheads required by the WR44 to route through tunnels affects the throughput.

Answer 1

Hi

i would think you would see some hit on the performance when adding some form of encapsulation you can check how the CPU is doing when you send data.

connect to the router over the serial interface
switch on debug to the serialinterface

debug 0

switch on the CPU monitor

cpumon 1

you should see the cpu level each second

you can do this over telnet as well but there could be a hit on performance and timing as its over a network connection but to switch on debug for telent

debug t

if you see the cpu running above 90% then that could be the issue

regards

James

Answer 2

Thanks James. Reading around there does seem to be a general issue with loss of performance when encapsulating in any type of tunnel, it just seems the Digi suffers a bit more. I've compared this with a Bintec router over 4G, just waiting for a Cisco 4G card to arrive so I can test with that.
I'll take a look at the CPU also.

David