US Cable Support > Comcast HSI > [Connectivity] ibone vs cbone

reply to iansltx

Re: [Connectivity] ibone vs cbone

Tracing route to te-8-3-ar01.capitolhghts.md.bad.comcast.net [68.86.72.2]
over a maximum of 30 hops:
 
  1     1 ms    <1 ms    <1 ms  172.20.15.1
  2     *        *        *     Request timed out.
  3     9 ms    10 ms    10 ms  ge-1-39-ur01.romeoville.il.chicago.comcast
.net [68.86.118.229]
  4    12 ms    11 ms    12 ms  te-8-2-ar02.elmhurst.il.chicago.comcast.ne
t [68.87.231.90]
  5    14 ms    14 ms    14 ms  te-2-1-ar01.area4.il.chicago.comcast
.net [68.87.230.121]
  6    13 ms    14 ms    14 ms  te-4-1-cr01.chicago.il.cbone.comcast
.net [68.86.72.33]
  7    22 ms    22 ms    22 ms  te-1-1-cr01.cleveland.oh.cbone.comca
st.net [68.86.68.21]
  8    22 ms    30 ms    30 ms  te-1-1-cr02.pittsburgh.pa.cbone.comc
ast.net [68.86.68.118]
  9    42 ms    42 ms    43 ms  te-2-1-cr01.mclean.va.cbone.comcast.
net [68.86.68.126]
 10    50 ms    50 ms    48 ms  te-8-3-ar01.capitolhghts.md.ba
d.comcast.net [68.86.72.2]
 

Tracing route to softlayer.com [66.228.118.53]
over a maximum of 30 hops:
 
  1    <1 ms    <1 ms     3 ms  172.20.15.1
  2     *        *        *     Request timed out.
  3    10 ms     8 ms    10 ms  ge-1-39-ur01.romeoville.il.chicago.c
omcast.net [68.86.118.229]
  4    10 ms    10 ms    10 ms  te-8-2-ar02.elmhurst.il.chicag
o.comcast.net [68.87.231.90]
  5    11 ms    11 ms    12 ms  te-2-1-ar01.area4.il.chicago.comcast
.net [68.87.230.121]
  6    16 ms    15 ms    13 ms  68.86.90.49
  7    35 ms    41 ms    38 ms  pos-0-0-0-0-cr01.indianapolis.in.ibo
ne.comcast.net [68.86.85.58]
  8    49 ms    51 ms    48 ms  pos-0-14-0-0-cr01.dallas.tx.ibone.comcast.net [6
8.86.85.153]
  9    42 ms    42 ms    50 ms  te1-2.cer02.dal01.dallas-datac
enter.com [75.149.228.34]
 10    50 ms    51 ms    51 ms  po2.dar02.dal01.dallas-datacenter.co
m [66.228.118.207]
 11    49 ms    49 ms    51 ms  po2.slr01.dal01.softlayer.com
[66.228.118.142]
 12    50 ms    50 ms    50 ms  www.softlayer.com [66.228.118.53]
 

I would think cbone is the local backbone, and ibone is national backbone and the gateway to the internet peering points. Thats just pure speculation on my part though

reply to timburke
Timburke, makes sense...so C is basically or Comcast/customer and i is for Internet. It's iteresting how many providers (ThePlanet, SoftLayer, FDCServers) now have Comcast as part of their mix...must be settlement-free or cheap, and probably helps Comcast with transit costs.

OTOH it also means that Comcast can route their network for cost, then flip the blame onto web hosts who haven't participated in their network; unless a target website uses Level3 in a big way, or Comcast's ibone for connection, it gets pretty highly routed. Sometimes it's not so bad; there's peering handoff in Chicago for an East-coast site. However a lot of traffic gets sent down t Santa Teresa, TX, then over to LA, then off the network to elsewhere (GBLX, TWTC, Cogent etc.). Granted, the performance drop is surprisingly low, but you're looking at 25 ms to Dallas/Softlayer on Comcast's network vs. 45 ms to Denver through LA on another network.

A slightly bigger deal: GNAX goes from Denver -> Santa Teresa -> LA -> PCCW/LA -> PCCW/ATL, for a total roundtrip time of ~70ms. Not horrible for the amount of routing around you get, but sub-optimal? Yep.

Even worse, Akamai isn't even directly connected to Comvsdt, so the "CDN" works slower for Comcast customers than people on other networks.