[ale] Slightly OT: Reasonable Latency with Comcast Business

[James Taylor]

Like Neal, my firewall is the only thing plugged into my comcast router,
and it is a Sophos XGS which is monitored by Sophos Central.
If I have an outage more than about 3 minutes, I get an email letting me
know.
For an long time, I was seeing outages which looked like router reboots
almost nightly.
I haven't seen that lately, though.

I did recently have a with of issues with latency, mostly with sites I
visit regularly. I had not rebooted the router in months, and after a
reboot, all the latency and dropped packets went away.

-jt 
James Taylor
678-697-9420
james.taylor at eastcobbgroup.com

>>> Lnx Gnome via Ale <ale at ale.org> 11/14/2024, 09:55 PM >>>
I'm surprised Comcast hasn't rebooted the gateway for you before now
(assuming it's their box). They often do config changes in the wee hours
of
the morning, and ours gets rebooted every month or two.

I used to run mrtg, like Derek, but just let my firewall monitor the
connection now, since it's the only thing plugged directly into the
Comcast
gateway. More often, I use uptimerobot (many cloud services should work)
to ping the Comcast WAN IP on the gateway, one of our ext static IPs on
the
firewall, and the IP of the DMZ Proxy (the firewall happily passes it).

On Thu, Nov 14, 2024 at 11:08 AM Neal Rhodes via Ale <ale at ale.org>
wrote:

> Thanks for the reply.
>
> I just got off the phone with Comcast. To my delight it only took 12
> minutes total.
>
> Their criteria is, they don't get concerned until:
>
> - Packets get lost;
> - Latency exceeds 100ms.
>
> To which I can only say, wow.
>
> Comcast tech also says I should reboot their router. (uptime over 140
> days.)
>
> My bet is the Ubiquiti router has much tighter assumptions. Next I
need
> to ask them precisely what their criteria is for concluding
disconnection.
>
> regards,
>
>
> Neal
>
> On 2024-11-14 10:56, Derek Atkins wrote:
>
> Hi Neal,
>
> I ditto what James says (and was going to say the same thing). Take a
> laptop that you KNOW can handle 1Gb, to be sure it's not a laptop
> limitation, and then plug into the router to be sure you can show the
> issue from their CPE. Showing it from the Ubiquiti equipment is not
> sufficient.
>
> Also, it helps if you can have a tech on the phone while the problem
is
> occurring. I used to have Comcast Biz and would lose network every
time
> there was a neighborhood power outage. It took a 3hr outage during the
> day and me calling just as the outage stopped for them to find the
node
> with the bad battery.
>
> So back to your issue. It looks like it could be a network drop, a
DHCP
> renew that takes too long, or possibly even an upstream issue with
> Comcast.
>
> Expect to spend time trying to reproduce it, especially if it's
something
> that isn't reliably reproducible. You might also want to look at
> potential buffer bloat, and also explore the possibility of NAT Table
> overload.
>
> Having said that, the RTT you see (17ms) is reasonable for a
cablemodem
> plant.
>
> -derek
>
> On Thu, November 14, 2024 10:41 am, James Taylor via Ale wrote:
>
> My experience with Comcast Business says that the you need to spend
time
> in the furnace room.
> They are going to test from their router and if you don't show the
problem
> there, they are unlikely (i.e. - never) to look further.
> -jt
>
> James Taylor
> 678-697-9420
> james.taylor at eastcobbgroup.com
>
> Neal Rhodes via Ale <ale at ale.org> 11/14/2024, 10:36 AM >>>
>
> This feels like a classic three party finger pointing exercise, and
I'm
> doing a bit of research before we jump in.
>
> A couple of years ago, our church put in a sophisticated (at least by
MY
> Measure) Ubiquity Unifi Mesh network, mostly to support security
camera
> for the community pre-school.
>
> The core is a UDM Pro router, feeding all Ubiquiti stuff.
>
> And it has run totally steady.
>
> Here's the rub: Now that the "Last Guy That Touched it" moved to
> Florida, I'm getting multiple alerts per day to the effect of:
>
> * Your prima> restarting your ISP Modem.
> * Primary internet is experiencing high latency. Please restart the
> modem or contact the ISP if this persists.
>
> Aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaand, nobody complains. Occasionally,
> I will see Zoom meetings from home where the church participants go
> really fuzzy and blocky, like Zoom has downshifted their resolution.
>
> Apparently it measures ping time to Ping.UI.Com to decide this.
>
> The Unifi Console reports the Comcast Business router as providing
> typical 14ms latency. With the occasional spike to 45ms.
>
> When I ping that address from my Uverse internet from home, I'm seeing
> consistently results from 7ms to 10ms.
>
> I don't know whether to ask Ubiquiti about raising their thresholds,
or
> Nag Comcast about their performance. I guess I could ask Ubiquiti
> precisely what does "Internet Disconnected" mean?
>
> My personal experience with Business Comcast in the past has
been.......
> not impressive. Usually, a service call just makes it worse. Is
> Comcast going to take my report from Ubiquiti seriously? Or tell me to
> pound sand? What additional evidence need I present?
>
> Yes, I could spend a quality hour in the furnace room, with a notebook
> connected to the LAN side of the Comcast router, (the only way I can
> talk to it) and see what I can see.
>
> I suppose I could just call Comcast, and give up another hour of my
life
> to try and talk to someone with a clue.
>
> regards,
>
> Neal
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