I want to use config 1, but we have had terrible luck with it (makes
things randomly worse).
Subframe change has to be system-wide only in cases where a CPE can
potentially hear more than one eNB on the same channel, or two eNBs on
the same channel can hear each other or are otherwise colocated with
each other, right? If you have 3 sectors each on a different channel
on top of a tower in the middle of nowhere, I'd think you could safely
choose a different config on each of them if desired.
Also, is the main subframe config the only thing that has to be
consistent, or does special sub also have to be as well? If we have
eNBs with differing cell-radius set, I would like to set the SSF to be
the optimum for that cell-radius size on an eNB by eNB basis to eke
out the best performance on each one.
-- Nathan
*From:*[email protected] [mailto:[email protected]] *On
Behalf Of *Adam Moffett
*Sent:* Saturday, December 31, 2016 9:31 AM
*To:* [email protected]
*Subject:* Re: [Telrad] Uplink capacity
On an eNB with 40 CPE, we've observed that we don't get more than
300-400kbps upload on a single UE....and yeah the eNB flattens out
before I think it should.
We're on a 20mhz channel, Configuration 2, SSF 2, and 2x4. We will
compare with 2x2. We might try Config 1, but since that's a system
wide change it won't be right away.
I think it's understood that you only get 16QAM upload right now, but
I was under the impression that was an issue with the CPE. I'm know
some of you have experimented with 3rd party CPE, and I'm wondering:
Do you get more upload speed with those and does 64QAM uplink works
with them?
-Adam
We are still fighting upload capacity problems on our more loaded
sectors.
To catch y'all up, we are running 15MHz channels and subframe
profile 2.
Some observations I have made:
1. Those eNBs running 6.6 seem to peak out on upload capacity at
around 85% utilization, according to BreezeView. Has anyone else
noticed this? When upload is getting hammered, the KPI graphs
flatline uplink utilization at 85% and it NEVER crosses that
line. eNBs on 6.5 will still approach 100%. Is this just a
reporting bug or what?
2. With the combination of 15MHz channels + subframe profile 2, we
seem lucky if we can ever push a total combined uplink rate of
2Mbit/s from all attached CPEs. Does this sound right to anyone?
This seems very low to me. And as I said in an earlier post, our
retransmits are below 2% and uplink MCS is staying at 20 or higher
> 90% of the time. (I am currently observing the same eNB as I
referenced in that earlier post.)
Also, what are current best practices as of 6.6? With the
introduction of weak UE protection, is it advisable to turn that
on and then go back to EqualRate scheduling?
I have set this particular Compact (30 CPEs) to EqualRate on both
down and up, and activated weak UE @ level 2 with the default MCS
indexes for level 2. It's probably too early to tell, but I don't
think this is making a signficant difference.
-- Nathan
*From:*Nathan Anderson
*Sent:* Thursday, December 22, 2016 12:31 AM
*To:* [email protected] <mailto:[email protected]>
*Subject:* RE: [Telrad] More CPE8K woes
As a follow-up to the iperf bit, there is an "accept" rule at the
top of the iptables firewall input chain on the EPC for its
*management* IP. Maybe Telrad expects you to run iperf traffic
between ENB and EPC across the management VLAN and not the main
EPC interface/bearing VLAN. You should be able to have iperf
explicitly bind to the management interface on both ends (iperf -B
A.B.C.D where A.B.C.D is the management IP for either the EPC or
ENB in question that you are invoking this on) and then on the
client side specify the other end's management IP for the -c
parameter.
However, this only works if you don't have 'switching
vlan-assignment epc-access-if-list' defined on your EPC, as we
do. If you are using that for whatever reason (e.g., site-based
EPC instead of centralized, although there are other scenarios),
you cannot send management traffic directly between the EPC and
ENB. This isn't being blocked by iptables, but is something
happening at a lower level (something to do with how VLANs are
being tagged and forwarded between the various ports and the
internal CPU port by the switch chip). Telrad may have failed to
consider this when adding the iperf feature.
-- Nathan
*From:*[email protected] <mailto:[email protected]>
[mailto:[email protected]] *On Behalf Of *Nathan Anderson
*Sent:* Thursday, December 22, 2016 12:14 AM
*To:* [email protected] <mailto:[email protected]>
*Subject:* Re: [Telrad] More CPE8K woes
Is it possible to get retransmission rates for uplink? I thought
only downlink stats were available from the eNB (which makes
sense, since the eNB would have no idea how many times each CPE
had to retransmit unless the CPEs were reporting that information
back to it somehow). Are you talking about pulling figures from
the CPE somehow, or getting this information elsewhere?
On the sector I'm looking at, single retransmit blocks in the DL
direction are about 1.4% of total blocks. According to old notes
I have, 1% is supposed to be good. I don't know whether I should
worry about the extra .4%, but I'm also not sure how this relates
to uplink health (if at all).
As far as percentages go for uplink modulation, 87% of all uplink
bits were sent MCS 23, if we include MCS 20 + 23 together that
rises to 91%, and if we include 19 + 20 + 23 together, that
accounts for 94%. Are those good numbers? They seem fairly good
to me. (I sure would love to see what individual CPEs are doing
for modulation in either direction at any given time...)
We have also been raising uplink AMBRs as well to help deal with
this. Which seems to help some, and which I think is weird that
it helps. For example, if I have uplink limited to 1.5Mbit/s, a
radio on this sector might be able to average 300-400kbit/s. If I
change that radio to an AMBR profile that has the uplink limit set
to 10Mbit/s, then all of a sudden in the same conditions (minutes
later, after changing that UE's profile and kicking it off the
EPC) I see more like 800-1000kbit/s from the same CPE! These
numbers are the same with both iperf TCP (on the radio) or
RouterOS bandwidth-test (router behind the radio), 5 parallel
streams in either case, very repeatable (at that same time of day).
What the...? If roughly 1Mbit/s of capacity is available, and a
given UE is set to 1.5Mbit/s of upload, why can't it achieve that
1Mbit/s unless I raise it to some crazy high number first? Why
does throughput instantly double when I lift that AMBR value?
So it sounds like you are telling me that you are doing a similar
thing and just cranking those AMBR numbers way up on the EPC, but
then you are using something else (RouterOS?) to queue packets up
upstream? And you get better performance this way? I believe it
based on what we have experienced (above), but it seems to me that
this really shouldn't be the case. Shouldn't the EPC be working
in tandem with the eNB to provide the best and most efficient
airtime utilization possible?
I don't think the issue with iperf is with you. I cut my teeth on
iperf2 and even I can't get it to work right on the Compacts and
BreezeWay. From what I can tell, problems appear to be
multi-fold. BreezeWay has a "drop all TCP connections
indiscriminately" rule at the end of its iptables firewall input
chain. That's the primary problem as far as I can tell. Once
that is out of the way, or an exception is added for TCP port 5001
earlier, it works, but the bundled iperf binary is somewhat buggy.
The -r and -d options don't work right and the device that is
playing the iperf server role fails to connect back to the other
in client mode and crashes out when it is time to run a
reverse-direction test. So you have to individually launch iperf
as a server on both ends separately in order to test both
directions. I remember running into a similar problem with the
iperf2 binary packaged with some version of Ubuntu a while back,
and I had to grab the iperf sources, patch them, and rebuild them
before that switch worked right. It appears Compact and BW both
have unpatched 2.0.5 with at least this bug present.
-- Nathan
*From:*[email protected] <mailto:[email protected]>
[mailto:[email protected]] *On Behalf Of *Jeremy Austin
*Sent:* Wednesday, December 21, 2016 10:22 PM
*To:* [email protected] <mailto:[email protected]>
*Subject:* Re: [Telrad] More CPE8K woes
On Wed, Dec 21, 2016 at 7:44 PM, Nathan Anderson <[email protected]
<mailto:[email protected]>> wrote:
but this upload capacity thing is what caused me to try pushing
6.6 out to more Compacts, even though I have read reports of
similar-sounding issues from others here who have fully
upgraded...just wanted to make sure I have all bases covered.
We haven't had stability issues per se with 6.6. We've had some
success raising upload AMBR, and shaping upstream.
What kind of retransmission rate are you seeing on the constrained
sectors in the upload direction, in extended stats? We have one in
particular that — despite having a verified clean channel — acts
as if it's experiencing interference. Despite a very high SINR!
And some truly bizarre spectrum analyzer results that aren't
corroborated by other, colocated ENBs.
I'm also not finding it easy running iperf between EPC and ENB, at
Telrad's recommendation. I must be more used to the syntax of
iperf3, because I don't have it correct yet.
--
Jeremy Austin
(907) 895-2311
(907) 803-5422
[email protected] <mailto:[email protected]>
Heritage NetWorks
Whitestone Power & Communications
Vertical Broadband, LLC
Schedule a meeting: http://doodle.com/jermudgeon
<http://doodle.com/jermudgeon>
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