[ale] Slightly OT: Reasonable Latency with Comcast Business

Fri Nov 15 10:20:47 EST 2024

The Comcast Router was restarted last night around 7pm.   Maybe a bit 
too early to tell for sure, but the office and pre-school activity has 
been running since 8am and it looks a bit less dodgy.

Still no response from Ubiquiti on their criteria.

On 2024-11-14 11:25, Derek Atkins wrote:

> What concerns me is the "empty" part of your graph..  At the 45ms peak,
> there appears to be a section of "no response".  Note that depending on
> the service being used, it's possible that the service is down.
> 
> FWIW, I run mrtg to monitor my network -- I run pings to several 
> different
> places to test latency across my uplink.  Specifically, one place I 
> ping
> is my 1st-hop upstream router.  If that router goes down or doesn't
> respond, it is 100% correlated to my connection being down for 
> everything.
> 
> Of course, YMMV.
> 
> -derek
> 
> On Thu, November 14, 2024 11:08 am, Neal Rhodes via Ale 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 primary internet Comcast Business was disconnected and has been
> restored multiple times in last 24h. If this persists, please try
> 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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