[185689] in North American Network Operators' Group
Re: Long-haul 100Mbps EPL circuit throughput issue
daemon@ATHENA.MIT.EDU (James Bensley)
Fri Nov 6 14:35:26 2015
X-Original-To: nanog@nanog.org
In-Reply-To: <CALKrK4na=wKSi=vf4EgPetoXJxaHTxfGt8HXYr6CE+xPk1Vy4g@mail.gmail.com>
Date: Fri, 6 Nov 2015 19:34:14 +0000
From: James Bensley <jwbensley@gmail.com>
To: nanog@nanog.org
Errors-To: nanog-bounces@nanog.org
On 5 Nov 2015 21:50, "Eric Dugas" <edugas@unknowndevice.ca> wrote:
>
> Hello NANOG,
>
> We've been dealing with an interesting throughput issue with one of our
> carrier. Specs and topology:
>
> 100Mbps EPL, fiber from a national carrier. We do MPLS to the CPE
providing
> a VRF circuit to our customer back to our data center through our MPLS
> network. Circuit has 75 ms of latency since it's around 5000km.
>
> Linux test machine in customer's VRF <-> SRX100 <-> Carrier CPE (Cisco
> 2960G) <-> Carrier's MPLS network <-> NNI - MX80 <-> Our MPLS network <->
> Terminating edge - MX80 <-> Distribution switch - EX3300 <-> Linux test
> machine in customer's VRF
>
> We can full the link in UDP traffic with iperf but with TCP, we can reach
> 80-90% and then the traffic drops to 50% and slowly increase up to 90%.
>
> Any one have dealt with this kind of problem in the past? We've tested by
> forcing ports to 100-FD at both ends, policing the circuit on our side,
> called the carrier and escalated to L2/L3 support. They tried to also
> police the circuit but as far as I know, they didn't modify anything else.
> I've told our support to make them look for underrun errors on their Cisco
> switch and they can see some. They're pretty much in the same boat as us
> and they're not sure where to look at.
>
> Thanks
> Eric
Hi Eric,
Sounds like a TCP problem off the top of my head, however just throwing it
out there, we use a mix of wholesale access circuit providers and carriers
for locations we haven't PoP'ed and we are an LLU provider (CLEC in US
terms). For such issues I have been developing an app to test below TCP/UDP
and for pseudowires testing etc:
https://github.com/jwbensley/Etherate
It may or may not shed some light when you have an underlying problem
(although yours sounds TCP related).
Cheers,
James.
