Comcast latency Maryland area

Lincoln Dale ltd at interlink.com.au
Wed Nov 30 06:59:53 UTC 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.




More information about the NANOG mailing list