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About rkmfl
since
04-08-2018
07-26-2018
rkmfl
Frequent Visitor
13
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3
Kudos
1
Solution
05-01-2018
07:48 AM
@nerdburg,
Thank you for escalating. Much appreciated. I'm very eager to find an engineer with a hands-on knowledge of this build. By the way, this is Arris' new turnkey setup that they seem to be pushing quite a bit.
Part of me wonders if there are not many people within Comcast that know much about this. I don't believe the reason is because it's proprietary (Arris publishes a great deal on this setup, promoting it so heavily). Instead, I wonder if the issue is that Comcast is simply following Arris' lead and Arris' marketing hyperbole, without having many people @Comcast who are up-to-speed on dialing-in the network issues, at this early stage.
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05-01-2018
05:10 AM
@nerdburg - That you for your reply. I suspect was my post ran a bit long and you may have missed some details. This is not OFDM / DOCSIS 3.1. Thiis is 32x bonded DOCSIS 3.0 (QAM256) channels down (3x up QAM64), using an HPON (Hybrid PON). It may sound crazy, but the fiber is nothing more than a coax replacement -- between the Node and the SDU.
To clarify, I've witnessed this topology first-hand, from the SDU to the EDFA (the EDFA in thsi case replaces a CMTS in a fiber-deep config).
@EG - Yes, You're 100% correct -- We have a HPON / RFoG without any PON passthrough. This is fiber passing RF-wave emulation to the SDU, not binary data. The CPE is the Arris ONU with ALC as you meneiond ( "ALC" is the Arris "automatic level control" that intentionally delivers +19dBmV).
As a reminder, this is affecting over 1,100+ homes, not limited to my service. This is a new Comcast build under an 8-year "bulk deal" (HOA community).
Most of the 1,100+ homes have similar issues. This isn't a Comm Tech 5 application (IMHO) because it's not limited to a handful of installs with issues, it's the overall design/build (or possibly issues at the HPON or EDFA).
Comcast has provided us with two of their head "Technical Operations Managers" that do not have an in-depth knowledge of this specific technology, based on statements they made to me (in fact, they claimed it's impossible to provide gigabit over coax in a deep-fiber HFC, with a community of this size, at which point I realized I was dealing with the wrong people). I've dealt with true technical engineers at MSO's and they are brilliant. These are not engineers, but managers with a 10,000-foot understanding of the tech.
II'm really hoping to get a true engineer/architect involved, in light of the size of the build. Hoping I find someone familiar with this unnusual build. Any ideas how I might find that person?
Thank you in advance!
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04-30-2018
07:15 AM
@ jweaver0312
Thank you for the reply. I absolutely agree about the downstream signal level.
I don't know whether you noticed, but towards the end of the post I mentioned the Arris ONU / CPE that converts fiber to RF, intentionally regulates the output to +19 dBmV and this cannot be regulated by Comcast because the ONU is fixed and will adjust to this output no matter the RF signal over fiber. My guess is that it's intended to be used with the SV8G 8-port splitters (10.8 to 12 dB loss across each output) installed on the other homes that have TV's. In my case, I don't have TV's, but I have tested the SV8G and it does bring me down to about 7.99 dBmV on average. The SNR stays the same, the performance stays the same, etc. It's surprising to me that everything runs the same between ~19 and ~8 dBmV, but that is the case currently.
If you're interested, you can see the Arris CP8051U ONU (Fiber-to-RF) here:
http://www.arris.com/globalassets/resources/data-sheets/1510791-reva_cp80x3-5-6-8u-02-10_family-sdu-r-onu.pdf
Most Importantly -- Is there anyone from Comcast that can involve someone with experience of this unique topology? We don't have that person here locally in Palm Beach County that I know of. If we do, we have not found him yet.
Thanks again!
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04-30-2018
05:07 AM
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Comcast installed new service they labeled “ Gigabit FTTH ” (with XB6 Gateways) in our community of 1,100 homes.
The install was finished about 2.5 months ago, I have personally been running the service for a month in my home.
Most of our community has voiced concerns this new “Gigabit” service is slower than their former “Blast” service (30 - 150 Mbps previously).
More than half of our community’s XB6 gateways are re-syncing 3+ times a day, causing about 8+ minutes downtime multiple times per day.
I’ve worked for MSO’s (many years ago), and I realize you need something more specific:
Comcast techs (and supervisors) have worked on many homes in our development. No issues have bee found, no fixes implemented.
Knowing this field very well, I’ve asked many of these techs (and supervisors) related questions, not one of them is familiar, or educated in our community’s unique build.
Some background on our unusual build:
· Comcast installed an HPON/RFoG network, not true FTTH
· RF Only (no PON Pass-through) @5-42 Mhz Upstream, still using old ~500 Mhz band Down
· From the Headend to SDU, it looks something like this:
Plant <-fiber-> EDFA <-fiber-> 5x Nodes (Arris HPON passive splitters) <-fiber-> CPE (less than 250 HHP’s per node)
· For the CPE:
<-fiber from HPON -> Arris HPON RFoG SDU ONU #CP8051U (RF Only) <- RG6 Coax -> 6 DB Attenuator <> XB6 Gateway
To Answer the Forum Prerequisites:
Make and model of your modem
Arris TG3482G (aka XB6) + external fan (to assure no issues with heat)
- HW Version: 9
- BOOT Version: 0.1.9.430478
- Download Version: 7.1.0.53 (updated April 26 th 2018, previously at 2.0.2.209 )
Make and model of your router
For diagnostic purposes, I’ve run the XB6 as a gateway and in Bridge-Mode.
In Bridge-Mode, Router: Ubiquiti EdgeRouter ER8- Pro , 8 Gbps 650k PPS speed)
Have you contacted Comcast / Tech Visit
Multiple tech visits for most people in our community. No resolution.
Signal Reset / Verified Provisioning Tier, many times with many community members
Modem light behavior when issues occur
Complete Headend Re-sync Process (8+ minutes down, identical to signal reset pattern)
Modem Error Logs
Absolutely nothing (not one single row) in my system logs relating to signal (login, settings change, nothing else)
Keep in mind that in our topology, the ONU connects the XB6, making this a very short/clean signal, high SNR, no errors, etc.
My Own Personal Experience with Service
I have adequate equipment in my house (8 Gbps router, Enterprise 10 GbE + 1 GbE Switch)
I also have AT&T Gigabit Fiber Service (true FTTH)
I previously had Comcast Blast 150 (on former fiber-deep HFC, ran perfect, approx 190 Mbps Downstream 24x7)
AT&T Fiber runs 930-940 Mbps Down, 920-938 Mbps Up (typically) 24x7. Real-world DSL-Reports Speedtest &
CDN’s, always over 800 Mbps
Comcast Gigabit runs 100-300 Mbps DS, 42 Mbps UStream. Real-World downloads on high-capacity CDN's within
20ms and one peer-point, less than 180 Mbps
I only use Internet. No TV’s, No Splitters, No exposed F-Connectors
Because AT&T runs 930+ Mbps (14 months now, tested 24x7), it should be clear the issue is not inside the premise
No security/anti-virus/proxy software is running on test systems
Tested with XB6 as gateway (modem+router) (and) as Bridge-Mode with external router
From my modem to Comcast’s Ookla Server in Miami, runs 9ms consistently.
Speed Test Summary (conducted all hours, including 2am-to-7am)
· 11ms by speedtest.xfinity.com 500-600 Mbps Down, 42 Mbps Upstream
· 50ms avg by dslreports 350-500 Mbps Down, 42
Mbps Upstream
· 9ms to Miami-Comcast Ookla 190 to 266 Mbps Down, 32-42
Mbps Upstream
· 14ms to Miami-Ookla server 140 to 170 Mbps, 32-42
Mbps Upstream
· Bufferbloat 30ms
Down, 150-200ms Upstream
Real-World File Downloads
· Geographically Multi-Homed Servers on Gigabit Uplinks 300 to
580 Mbps
· Peered with Comcast 170
to 460 Mbps
· Optimized, Distributed CDN Content (Google Drive, etc) 80 Mbps
Max
· Uploads to AWS, Azure, Google Drive (closest geo) 28
Mbps Max
Signal Levels and Modulation, Pasted directly from XB6 (Arris TG3482G)
Downstream
Index
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Lock Status
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Frequency
513 Hhz
459 Hhz
465 Hhz
471 Hhz
477 Hhz
483 Hhz
489 Hhz
495 Hhz
507 Hhz
519 Hhz
525 Hhz
531 Hhz
537 Hhz
543 Hhz
549 Hhz
555 Hhz
SNR
40.366
40.366
40.946
40.366
40.366
40.366
40.366
40.366
40.366
40.366
40.946
40.946
40.366
40.366
40.366
40.366
Power Level
17.700
17.700
17.500
17.400
17.500
17.600
17.700
17.700
17.600
17.800
17.800
18.000
18.100
18.200
18.300
18.200
Modulation
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256
Downstream
Index
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
Lock Status
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Locked
Frequency
561 Hhz
567 Hhz
573 Hhz
579 Hhz
585 Hhz
591 Hhz
597 Hhz
603 Hhz
609 Hhz
615 Hhz
621 Hhz
627 Hhz
639 Hhz
645 Hhz
651 Hhz
657 Hhz
SNR
40.946
40.946
40.366
40.366
40.366
40.366
40.366
38.983
38.983
38.605
38.983
38.983
38.983
38.605
38.605
38.983
Power Level
18.200
18.400
18.300
18.500
18.500
18.400
18.400
18.500
18.400
18.400
18.500
18.400
18.200
18.100
18.000
17.900
Modulation
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256
QAM256
Upstream
Index
1
2
3
Lock Status
ACTIVE
ACTIVE
ACTIVE
Frequency
29.4 Hhz
23 Hhz
35.8 Hhz
Symbol Rate
5120 KSym/sec
5120 KSym/sec
5120 KSym/sec
Power Level
35.771
35.771
36.271
Modulation
64QAM
64QAM
64QAM
Channel Type
US_TYPE_STDMA
US_TYPE_STDMA
US_TYPE_STDMA
Relating to the Signal Stats:
I did not paste the Error Codewords ; they are zero (0) on all 32 channels, in every instance (signal is perfect via adjacent ONU)
The DS power level may appear high ; however, this is a “feature” of the ONU which regulates the RF output to +19 dBmV (according to Arris)
You can see this is a 32x3 D3.0 Bonded modulation, yet we were promised true FTTH Gigabit
This is a new , fresh build by Comcast (8yr contract) , finished only 2.5 months ago
We received an HPON running RF only (no PON passthrough) on the legacy/traditional ~500/40 Mhz bands
We did not receive a true FTTH/PON, not even DOCSIS 3.1 (OFDM 2x2)
I’m not making these points to complain.
Rather, I believe the difference between what was promised -- versus what we received -- may be playing a role in the mysterious issue affecting everyone. That, and the
lack of information/schooling by anyone involved in supporting this network.
For example, it appears to be clear that Comcast intended to install a true PON, or at least 3.1, and something happened along the way.
None the less, we’ve had dozens of techs, the supervisors, and the head of the departments. Not one of them has determined the cause of our issues, or any working fix.
The primary issues again:
(1) More than half of our homeowners XB6 modems are re-syncing to the headend multiple times per day, causing 8+ minute outages in each instance.
(2) Speeds are exceptionally slow. Both privately to Comcast’s local Ookla server 9ms away, and worse, the On-net speeds (Comcast claims utilization is at 25%)
(3) Real-world browsing is ever slower than speed-tests/downloads. Slower than previously “Blast” packages with Comcast. Almost appears to be an issue with the XB6 Puma-7 SoC. For example,
I’ve max’ed the upload speed and been unable to download until the upload completes.
Is there anyone within Comcast who is more familiar with this topology, who can get involved? While I will give you all the time in the world with my setup and aiding your testing -- please know this is
affecting most of our 1,100 homes for the next 8 years and is causing many people a great deal of problems (particularly home-workers).
Thank you in advance for any insight!
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