North American Network Operators Group

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Re: Comcast latency Maryland area

  • From: Lincoln Dale
  • Date: Wed Nov 30 02:01:55 2005


you don't say the ip-addr-block where you're doing a traceroute _from_.
perhaps your private address space NATs into 73.138.40.1?

looks more like assymetric routing to me with _return traffic_ from AT&T and L3 taking a far longer path back to you.

checking my connectivity to there, it looks perfectly normal.


assuming that its a OC48 POS connection between hops 7 & 8 (big assumption, but bear with me), 160 msec of queuing latency equates to 47 megabytes of buffering on that link. [1]. unlikely.

if we assume its a GbE connection at hops 7 & 8, then it'd be 19 megabytes of buffering. [2]. still unlikely.

i guess it COULD be a 7 Mbps DSL connection .. yeah .. that'd be it .. a DSL router with 128KB buffering.. :) [3]. (this one is obviously a joke)


[1] (2488*10^6 / 8) * (0.250 - 0.090) / (1024*1024)
[2] (2488*10^6 / 8) * (0.250 - 0.090) / (1024*1024)
[3] (7*10^6 / 8) * (0.250 - 0.090) / (1024)


did you lodge a trouble ticket with comcast if you feel they have a problem?


cheers,

lincoln.

Mark Owen wrote:
Congested router?


Tracing route to google.com [72.14.207.99]
over a maximum of 30 hops:

  1    <1 ms    <1 ms    <1 ms  192.168.20.1
  2    15 ms     6 ms     5 ms  73.138.40.1
  3     7 ms     6 ms    26 ms  ge-2-3-ur01.lanham.md.bad.comcast.net [68.87.131
.113]
  4     6 ms     7 ms     7 ms  te-9-1-ur01.bowie.md.bad.comcast.net [68.87.128.
177]
  5     7 ms     8 ms     7 ms  te-8-2-ar01.capitolhghts.md.bad.comcast.net [68.
87.128.182]
  6    17 ms    23 ms    15 ms  68.87.16.153
  7    92 ms    92 ms    91 ms  pos-0-0-cr01.whitemarsh.md.core.comcast.net [68.
87.16.21]
  8   250 ms   253 ms   254 ms  12.118.102.5
  9   259 ms   263 ms   257 ms  tbr1-p010101.n54ny.ip.att.net [12.123.3.82]
 10   255 ms   252 ms   253 ms  ggr2-p300.n54ny.ip.att.net [12.123.3.58]
 11   294 ms   284 ms   275 ms  so-7-1.car3.NewYork1.Level3.net [4.68.127.5]
 12   283 ms   286 ms   283 ms  ae-1-56.bbr2.NewYork1.Level3.net [4.68.97.161]
 13   267 ms     *      277 ms  as-1-0.bbr1.Chicago1.Level3.net [64.159.0.237]
 14   277 ms   286 ms   278 ms  ae-12-51.car2.Chicago1.Level3.net [4.68.101.3]
 15   253 ms   260 ms   263 ms  unknown.Level3.net [209.247.34.26]
 16   279 ms   278 ms   288 ms  64.233.175.97
 17   274 ms   309 ms   289 ms  66.249.94.69
 18   292 ms   272 ms   290 ms  66.249.94.73
 19   275 ms   268 ms   293 ms  72.14.207.99

Trace complete.