Well now you've got me curious.  We have a second BreezeWay that we intend to 
use as a geographically-redundant EPC, but we haven't gotten around to putting 
it into full service yet (we didn't even have all of our ENBs running 6.6 until 
relatively recently, and that was a prerequisite for the primary/secondary S1 
redundancy feature).  I can't reconfigure our primary EPC for 
non-"epc-access-if-list" mode on a whim as that would be extremely disruptive, 
but I am seriously considering putting our other BreezeWay into single-port 
mode in order to try running some iperf tests over the management VLAN, and see 
if my memory on this issue is correct.

LAGs I believe have been supported for the epc-network-if-list port for quite 
some time (since first GA release I'm almost sure), and I *believe* that they 
are also supported for epc-access-if-list ports, but don't hold me to that.  
Even if they were, though, I have no intention of configuring one since as far 
as I can tell, LAGs are strictly statically defined and there is no LACP 
support.  (I might change my tune on LAGs once we start topping out 1Gbit/s on 
user traffic, though; heh.)  Maybe I'm overthinking things, but I would be 
concerned about having a network partition event downstream of one port or the 
other that wouldn't affect the link state of that port on the BreezeWay.  Thus 
LAGs without LACP can't really be (effectly) used for proper L2 redundancy, 
just for doubling traffic capacity.  I would love to see LACP support come to 
the BreezeWay someday, but I have no idea if it is even on the roadmap...

Correct, we don't have any recorded test results of routed vs. bridged iperf 
between ENB and EPC.  At one point when we were struggling with that damned 
RB1100 switch chip issue (without knowing yet what was at fault), we tried 
routing traffic to one of our ENBs instead to see if that helped at all...the 
suspicion at the time was that VPLS itself was possibly the cause of our 
performance woes, so we were trying to remove it from the equation.  As I 
recall, performance to that ENB was comparable before vs. after: switching to 
pure routing made effectively zero difference.  We do have a spare Compact on 
the ground (for when a production one flames out and we need to replace it in 
an emergency), and I could *probably* do the same thing with it and put a 
couple of routers in between it and our EPC.  I'm trying to think through 
whether that would even work with epc-access-if-list defined...

Anyway, feel free to send me your results.  I'll see what I can do on my end to 
set up a "lab"-ish environment using our spare EPC and ENB (or both).

-- Nathan

From: [email protected] [mailto:[email protected]] On Behalf Of 
Jeremy Austin
Sent: Monday, January 30, 2017 8:41 PM
To: [email protected]
Subject: Re: [Telrad] Issues



On Mon, Jan 30, 2017 at 6:38 PM, Nathan Anderson 
<[email protected]<mailto:[email protected]>> wrote:
...though I should warn you that we are using epc-access-if-list as detailed in 
past posts of mine, so we are unable to have our ENBs talk to our EPC over the 
management VLAN.  Thus we can only run iperfs between ENB and EPC over the S1 
VLAN, which isn't something you can normally do (due to iptables filter rule 
installed by Telrad on EPC side).

I had intended to use epc-access-if-list, but I wasn't able to make that work 
and still have L2 redundancy. I might have missed something obvious? Honestly 
I'd be fine with a LAG, but I wasn't 100% sure it is supported yet. (Or better 
yet, a 10G interface.)

I am pretty sure that that filter rule wasn't there previously (probably in 
initial 6.5 release), and although I cannot recount the details, I also seem to 
recall that we saw significant differences between iperf tests over the 
management VLAN and iperf tests over the S1 VLAN.  I want to say the tests over 
the management VLAN were notably worse, and since we knew traffic between 
devices was not running over that VLAN anyway, we didn't care and discounted 
those results.  At the time I figured that Telrad had optimized for performance 
over the S1 VLAN somehow at the expense of the management one; nothing else 
could make sense of the difference.

Because we're using L3 EPC<>ENB and the VLANs are only relevant at the last 
hop, I was assuming that performance would be the same on mgmt vs. S3. And 
Telrad did iperf testing on my network *using management*, and those were the 
results I was trying to replicate.

So if I understand you correctly, you haven't tested iperf to management on 
both L2 and L3? This would have to be contrasted with S1 (again, L2 and L3), 
which you can't do with your setup.


We also switch (well, okay, VPLS) all traffic between ENBs and the EPC so (from 
the ENB and EPC's perspective) there is no L3/routed infrastructure sitting 
between them.  So the way we have our network set up may not be an 
apples-to-apples comparison with yours.


I'm leaning toward this topology, unless S1 routed performance is identical to 
switched — but this isn't what Telrad tested!

What Telrad was trying to prove was that S1/backhaul performance is inadequate 
and causing some performance issues. I was unconvinced, as the results were 
significantly poorer than router-to-router testing. And in attempting to 
replicate them, I discovered that iperf using management is radically different 
on L3 vs L2.



-- Nathan

From: [email protected]<mailto:[email protected]> 
[mailto:[email protected]<mailto:[email protected]>] On Behalf Of 
Nathan Anderson
Sent: Monday, January 30, 2017 7:21 PM

To: [email protected]<mailto:[email protected]>
Subject: Re: [Telrad] Issues

Oh I see, gotcha.  Happy to help off-list if that's where you want to take it.

-- Nathan

From: [email protected]<mailto:[email protected]> 
[mailto:[email protected]] On Behalf Of Jeremy Austin
Sent: Monday, January 30, 2017 7:19 PM
To: [email protected]<mailto:[email protected]>
Subject: Re: [Telrad] Issues

Nathan, I can send you more details off list. I should have been clearer; I'm 
getting different results when testing iperf on L2 to the EPC management 
network vs. L3 to management, even when taking bandwidth delay product into 
account.
Thanks... more later.
On Mon, Jan 30, 2017 at 6:08 PM Nathan Anderson 
<[email protected]<mailto:[email protected]>> wrote:
Can you detail your specific results?

I'll try to run some iperfs between our ENBs and EPC so we can compare to 
yours, but we are not doing L2 PDNs so not sure how much help we can be there.

-- Nathan

From: [email protected]<mailto:[email protected]> 
[mailto:[email protected]<mailto:[email protected]>] On Behalf Of 
Jeremy Austin
Sent: Monday, January 30, 2017 7:01 PM

To: [email protected]<mailto:[email protected]>
Subject: Re: [Telrad] Issues


On Sun, Nov 20, 2016 at 2:13 AM, Nathan Anderson 
<[email protected]<mailto:[email protected]>> wrote:
Which again leaves us at square one as far as explaining what is going on, but 
at least we now have a working solution.  So, huzzah for that.  Ever since 
moving the EPC trunk port to a different port on our LTE core router, I have 
been able to do 60Mbit/s single-stream TCP tests to UEs that are multiple hops 
out on our microwave backbone.  I have NEVER been able to accomplish this 
before, much less consistently.  I think that using the word "giddy" here to 
explain our disposition ever since we made this discovery would be a vast 
understatement.

To revisit an older thread, has anyone else done iperf tests between ENB and 
EPC and found a bottleneck that wasn't a backhaul? I'm getting radically 
different L2 vs. L3 results, and it does seem to be narrowed down to the EPC.

S1 and PDNs are on the same switch port.


--
Jeremy Austin

(907) 895-2311<tel:(907)%20895-2311>
(907) 803-5422<tel:(907)%20803-5422>
[email protected]<mailto:[email protected]>

Heritage NetWorks
Whitestone Power & Communications
Vertical Broadband, LLC

Schedule a meeting: http://doodle.com/jermudgeon
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Telrad mailing list
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[email protected]<mailto:[email protected]>
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--
Jeremy Austin

(907) 895-2311<tel:(907)%20895-2311>
(907) 803-5422<tel:(907)%20803-5422>
[email protected]<mailto:[email protected]>

Heritage NetWorks
Whitestone Power & Communications
Vertical Broadband, LLC

Schedule a meeting: http://doodle.com/jermudgeon
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