the original post asked for: "I connected to my cable modem and fired up my packet sniffer. I did not see anyone elses traffic on the line so "
--- bergenpeak wrote: > Hi Sam, > > The shared vs non-shared issue DSL providers mention > is somewhat > misleading. In any residential cable or DSL > network, you will > have stat muxing. In a cable network, this happens > on the HFC > network. In a DSL network, this happens at the Agg > router (the > one that terminates all of those DSL connections). > The Internet > is one big stat mux. In either the DSL or Cable > approach, the > customer observed performance will be a result of > many factors, > including access network design (how many subs share > the cable > or agg router), the behaviors of these other users, > the regional > network design, the size and types of peering > connections, and > where the users are actually surfing too. > > My house has a long driveway that only I use. Does > that mean > I'll get to work faster than the neighbors down the > street > which live in an apartment complex and share a > driveway with > other folks? > > In both approaches, one can prioritize traffic or > partition bandwidth > to certain groups of users. > > The current standard for how IP/ethernet frames are > transmitted over > an HFC network is defined via the DOCSIS 1.0 spec. > This specification > is available at www.cablelabs.com. This spec > defines how to > support best-effort IP transport. > > Support for additional features, include QoS, is > defined in the > DOCSIS 1.1 spec. This document is also available at > the above > web site. > > > Some details about DOCSIS cable networks: > > * On the HFC network, a single downstream channel > can support > ~25-35 Mb/s (depending on the modulation being > used). > > * The upstream connection typically can support > between 5-10 Mb/s > (depending on modulation and the size of the > channel). > > * The cable operator can opt, based on RF combining, > how many homes > (fiber nodes) share a downstream or upstream. > When service is > initially > launched in an area, an operator might combine > several nodes together > and as the take rate increases, reduce the amount > of combining > (which effectovely reduces the number of customers > who share the > bandwidth). > > * When a cable modem is brought online, it gets an > IP address via > DHCP and then is loaded with configuration > information (IP, L2, > and L4 filters), network management, etc > information. These > filters prevent issues which arise when DHCP > servers are > running in a customer's home, prevents my NETBIOS > traffic from being > seen by neighbors, etc. > > There are other technologies still deployed by cable > operators to > support > HSD (LanCity, Motorola CDLP, Com21, etc.) which may > not operate the same > as DOCSIS. > > Hope this helps. > > > > sam sneed wrote: > > > > I just changed services from DSL to cable modem. I > have heard from people, > > including verizon, that cable is not as secure as > DSL becuase it is over a > > shared medium. I connected to my cable modem and > fired up my packet > sniffer. > > I did not see anyone elses traffic on the line so > i am assuming the > bandwith > > is shared( a known fact about cable access) but is > somehow filtered at the > > cable modem(bridge). Does anyone know if this > assumption is true and the > > inside details of the how data is transmitted over > the cable network? A > link > > to a whitepaer would be great. > > > > thanks [EMAIL PROTECTED] __________________________________________________ Do You Yahoo!? Yahoo! Sports - live college hoops coverage http://sports.yahoo.com/ Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=38916&t=38705 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
