nanog mailing list archives

Re: Sub-optimal Charter/Spectrum (AS20115) routing from Greater KC Market

From: Josephina Lacy via NANOG <nanog () lists nanog org>
Date: Wed, 28 Oct 2026 12:42:51 -0500

Hi Patrick and Mel,

Thank you both so much for the incredibly kind words and encouragement!
Hearing this from engineers of your background completely made my week.

Mel, I’m definitely not an ISP insider, just a web developer who chased
this issue for hours because my Counter-Strike matches were lagging and my
neighbor's weren't. But I am absolutely tickled!

Patrick, your explanation makes perfect sense. It’s a fascinating look at
how the infrastructure layer actually operates behind the scenes.

I'm going to take your advice and get regional trouble tickets logged with
Spectrum to see if we can get the statistical needle moving. Thank you both
again for being so welcoming and taking the time to educate a developer who
wants to enjoy games with their friends. Also, I am never one to say no to
an opportunity to learn something new :-)

Best,
*Josephina Lacy*


On Wed, Oct 28, 2026 at 12:23 PM Mel Beckman <mel () beckman org> wrote:

,

Patrick,

Of course you are correct, cost is a primary driver. It’s not that I
forgot that, it’s just that I thought it was implicit in the ideas that
they are load-balancing or grooming and that’s usually done for cost
reasons. The primary one being not installing additional circuits :-)

And yes, I meant to congratulate Josephina on her excellent presentation
of the situation. She obviously knows her stuff, and gave a very concise, I
would call a model, analysis of the latency situation. I suspect she is a
Network Engineering professional, perhaps even in the ISP biz :-)

 -mel

On Oct 28, 2026, at 9:44 AM, Patrick W. Gilmore via NANOG <

nanog () lists nanog org> wrote:


Mel: You forgot (because I know you know this) the #1 reason ISPs do

traffic engineering: Cost.


For Josephina’s elucidation: Most networks will send traffic over free

peering before transit, even if peering is much high latency. In fact, they
are unlikely to even know the transit link is lower latency as they will
not even check. In their defense, peering is typically equal or even lower
latency, but not always.


In the case below, it would not surprise me if Spectrum only has peering

out of state while United Fiber has peering in state. Might not even be
peering vs. transit. It would also not surprise me if Spectrum has zero
external links in MO, so it has to go to Dallas / Chicago / whatever to
reach peering or transit. No interconnection, no way to pass traffic.


All that said, I would like to congratulate you Josephina. You have

managed to send a clear, polite, professional post with enough relevant
info to at least start a diagnosis. There are network engineers on this
list with a decade or more of experience that cannot seem to that. 😁
Hopefully someone on this list with an open position is smart enough to
offer you a job. I would if I could.


--
TTFN,
patrick

On Oct 28, 2026, at 11:34, Mel Beckman via NANOG <nanog () lists nanog org>

wrote:


I feel your gaming pain. But ISPs don’t necessarily engineer traffic to

optimize latency. Sometimes it’s for other reasons, such as load balancing
or WDM grooming. That’s proprietary internal information that they’re not
obligated to share, and likely won’t.


-mel via cell

On Oct 28, 2026, at 8:23 AM, Josephina Lacy via NANOG <

nanog () lists nanog org> wrote:


Hi NANOG,

I am a Charter/Spectrum (AS20115) residential subscriber out of the
northern Kansas City regional market (specifically Excelsior Springs,

MO).

I am posting to the list because multiple households across different
cities in our area (including Liberty, MO) are experiencing severe

routing

inefficiencies when targeting Midwest and Southern destinations.

I don't manage BGP topology myself, but looking at our traceroutes, it
appears that Charter’s internal backbone is consistently hauling
out-of-region Chicago and Dallas traffic to Denver, Western Nebraska

before

turning it back around. This introduces an unnecessary 30-60ms latency
penalty.

To illustrate the contrast, a regional competitor in the exact same
neighborhood (United Fiber, AS14371) successfully routes traffic

straight

from KC to Chicago in 22ms via Arelion, and reaches Dallas in 34ms.
Meanwhile, Spectrum subscribers are hitting 55ms-75ms minimum for the

exact

same endpoints due to internal multi-state detours.

I have compiled our local telemetry below to help any Charter backbone

or

peering engineers on the list look into why our regional aggregation

edge

is failing to use local path optimizations.


==============
1. CHICAGO (ORD) DESTINATIONS: SPECTRUM VS. UNITED FIBER
==============
Packets targeting Chicago from Spectrum route northwest into Nebraska,
encountering a severe 40-45ms latency step-up entirely within Charter's
internal transit hops before trailing up through Minnesota to reach
Illinois.

[Spectrum User 1 - Excelsior Springs, MO]
7    24 ms    26 ms    24 ms  lag-100.mcr01sctsnedc.netops.charter.com
8    67 ms    69 ms    69 ms  lag-9.mcr11sctsnedc.netops.charter.com
...
16    56 ms    58 ms    59 ms  162-254-193-71.valve.net

[Spectrum User 2 - Liberty, MO]
8    21 ms    19 ms    21 ms  lag-102.mcr01krnynegg.netops.charter.com
9    64 ms    63 ms    61 ms  lag-9.crr01gdisne.netops.charter.com
...
17    56 ms    53 ms    54 ms  162-254-193-71.valve.net

[United Fiber Baseline -  Excelsior Springs, MO]
United Fiber drops locally into a KC hub (MCI), hands off directly to
Arelion, and takes a clean line straight east to Chicago in 22ms flat:
4    13 ms    11 ms    10 ms  be6661.ccr22.mci01.atlas.cogentco.com
5    13 ms    11 ms    11 ms  arelion.mci01.atlas.cogentco.com
6    23 ms    22 ms    22 ms  chi-bb2-link.ip.twelve99.net
...
11    25 ms    24 ms    22 ms  162-254-193-71.valve.net


==============
2. DALLAS (DFW) DESTINATIONS: S

<https://www.google.com/maps/search/ESTINATIONS:+S?entry=gmail&source=g>PECTRUM
VS. UNITED FIBER

==============
To reach Dallas (approx. 500 miles directly south of KC), Spectrum

routes

traffic west to Denver, north through Nebraska and Minnesota, east to
Chicago, and back down south.

[Spectrum User 1 - Excelsior Springs, MO]
7    27 ms    25 ms    28 ms  lag-100.mcr01sctsnedc.netops.charter.com
8    69 ms    66 ms    66 ms  lag-9.mcr11sctsnedc.netops.charter.com
...
18    65 ms    62 ms    66 ms  162-254-194-1.valve.net

[Spectrum User 2 - Liberty, MO]
7    37 ms    32 ms    34 ms  lag-100.mcr01sctsnedc.netops.charter.com
8    66 ms    67 ms    68 ms  lag-9.mcr11sctsnedc.netops.charter.com
...
18    75 ms    75 ms    69 ms  162-254-194-1.valve.net

[United Fiber Baseline -  Excelsior Springs, MO]
4     8 ms     8 ms     8 ms  be6661.ccr22.mci01.atlas.cogentco.com
5    14 ms    11 ms    12 ms  be5591.ccr32.oma02.atlas.cogentco.com
6    22 ms    20 ms    21 ms  be5068.ccr42.ord01.atlas.cogentco.com
7    20 ms    21 ms    20 ms  be2766.ccr41.ord03.atlas.cogentco.com
...
14    34 ms    34 ms    34 ms  162-254-194-1.valve.net


==============
FULL SPECTRUM TRACEROUTE FOR REFERENCE
==============
[User 1 - Excelsior Springs, MO to Valve Chicago]
1    <1 ms    <1 ms    <1 ms  console.gl-inet.com
2     6 ms     8 ms     6 ms

vlan-200.ana05kscymogp.netops.charter.com

3    23 ms    19 ms    23 ms  lag-46.hcr11kscymogp.netops.charter.com
4     8 ms     6 ms     5 ms  lag-20.hcr02kscymogp.netops.charter.com
5    11 ms    10 ms     8 ms  lag-28.mcr01ksczksmp.netops.charter.com
6    26 ms    25 ms    24 ms  lag-101.mcr01dnvrco26.netops.charter.com
7    24 ms    26 ms    24 ms  lag-100.mcr01sctsnedc.netops.charter.com
8    67 ms    69 ms    69 ms  lag-9.mcr11sctsnedc.netops.charter.com
9    57 ms    56 ms    56 ms  lag-401.crr02gdisne.netops.charter.com
10    57 ms     *        *     lag-808.bbr01stcdmn.netops.charter.com
11    54 ms    54 ms    53 ms  lag-1.bbr02chcgil.netops.charter.com
12    55 ms    58 ms    57 ms  lag-802.prr01chcgil.netops.charter.com
13     *        *        *     Request timed out.
14     *        *        *     Request timed out.
15    57 ms    53 ms    57 ms  162-254-193-131.valve.net
16    56 ms    58 ms    59 ms  162-254-193-71.valve.net

[User 2 - Liberty, MO to Valve Dallas]
1     1 ms    <1 ms    <1 ms  SAX1V1S.lan
2    13 ms    16 ms    13 ms  syn-070-094-032-001.res.spectrum.com
3    31 ms   188 ms    30 ms  lag-58.hcr12kscymogp.netops.charter.com
4    18 ms    19 ms    16 ms  lag-21.hcr02kscymogp.netops.charter.com
5    13 ms    13 ms    17 ms  lag-28.mcr01ksczksmp.netops.charter.com
6    34 ms    35 ms    33 ms  lag-101.mcr01dnvrco26.netops.charter.com
7    37 ms    32 ms    34 ms  lag-100.mcr01sctsnedc.netops.charter.com
8    66 ms    67 ms    68 ms  lag-9.mcr11sctsnedc.netops.charter.com
9    75 ms    72 ms    73 ms  lag-401.crr02gdisne.netops.charter.com
10    77 ms     *       70 ms  lag-808.bbr01stcdmn.netops.charter.com
11    76 ms    72 ms    76 ms  lag-1.bbr02chcgil.netops.charter.com
12    88 ms    80 ms    78 ms  lag-22.bbr01olvemo.netops.charter.com
13    79 ms    84 ms    78 ms  lag-3.bbr01blvlil.netops.charter.com
14    73 ms    68 ms    71 ms  lag-805.bbr01dllstx.netops.charter.com
15    75 ms    70 ms    72 ms  lag-801.prr01dllstx.netops.charter.com
16   104 ms    69 ms    73 ms  162-254-194-144.valve.net
17     *        *        *     Request timed out
18    75 ms    75 ms    69 ms  162-254-194-1.valve.net

==============
FULL UNITED FIBER TRACEROUTE FOR REFERENCE
==============
[User 3 - Excelsior Springs, MO to Valve Chicago]
1     1 ms     1 ms     1 ms  router.home.local [192.168.1.1]
2    26 ms    16 ms    16 ms  38.148.167.1
3     7 ms     4 ms     4 ms  10.20.0.29
4    13 ms    11 ms    10 ms  be6661.ccr22.mci01.atlas.cogentco.com
[38.20.20.129]
5    13 ms    11 ms    11 ms  arelion.mci01.atlas.cogentco.com
[154.54.11.46]
6    23 ms    22 ms    22 ms  chi-bb2-link.ip.twelve99.net
[62.115.139.124]
7    19 ms     *        *     chi-b24-link.ip.twelve99.net

[62.115.137.29]

8    21 ms    22 ms    22 ms  valve-ic-392833.ip.twelve99-cust.net
[62.115.202.235]
9     *        *        *     Request timed out.
10    24 ms    22 ms    22 ms  162-254-193-130.valve.net

[162.254.193.130]

11    25 ms    24 ms    22 ms  162-254-193-71.valve.net

[162.254.193.71]


[User 3 - Excelsior Springs, MO to Dallas]
1     1 ms     1 ms     1 ms  router.home.local [192.168.1.1]
2    11 ms    15 ms    16 ms  38.148.167.1
3     6 ms     3 ms     4 ms  10.20.0.29
4     8 ms     8 ms     8 ms  be6661.ccr22.mci01.atlas.cogentco.com
[38.20.20.129]
5    14 ms    11 ms    12 ms  be5591.ccr32.oma02.atlas.cogentco.com
[154.54.89.2]
6    22 ms    20 ms    21 ms  be5068.ccr42.ord01.atlas.cogentco.com
[154.54.166.74]
7    20 ms    21 ms    20 ms  be2766.ccr41.ord03.atlas.cogentco.com
[154.54.46.178]
8     *       23 ms    21 ms

ix-bundle-19.qcore1.ct8-chicago.as6453.net

[66.110.15.38]
9    35 ms    34 ms     *

if-bundle-2-2.qcore2.ct8-chicago.as6453.net

[66.110.15.37]
10     *       34 ms    33 ms

if-bundle-63-2.qcore1.dl8-dallas.as6453.net

[66.198.29.35]
11     *        *        *     Request timed out.
12    34 ms    34 ms    34 ms  64.86.132.235
13     *        *        *     Request timed out.
14    34 ms    34 ms    34 ms  162-254-194-1.valve.net [162.254.194.1]

*Any help or insight from the Charter network team would be greatly
appreciated. I apologize for any errors. Feel free to ask any

questions!*


*Thank you!*
*Josephina Lacy*
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Current thread:

Sub-optimal Charter/Spectrum (AS20115) routing from Greater KC Market Josephina Lacy via NANOG (Oct 28)
- Re: Sub-optimal Charter/Spectrum (AS20115) routing from Greater KC Market Mel Beckman via NANOG (Oct 28)
  - Re: Sub-optimal Charter/Spectrum (AS20115) routing from Greater KC Market Patrick W. Gilmore via NANOG (Oct 28)
    - Re: Sub-optimal Charter/Spectrum (AS20115) routing from Greater KC Market Mel Beckman via NANOG (Oct 28)
    - Re: Sub-optimal Charter/Spectrum (AS20115) routing from Greater KC Market Josephina Lacy via NANOG (Oct 28)
    - Re: Sub-optimal Charter/Spectrum (AS20115) routing from Greater KC Market William Herrin via NANOG (Oct 28)
- Re: Sub-optimal Charter/Spectrum (AS20115) routing from Greater KC Market Jim Troutman via NANOG (Oct 28)