wow thanks for all the responses everyone! I learn something new everyday on this board.
scott ""[EMAIL PROTECTED]"" wrote in message news:[EMAIL PROTECTED] > Being in the "CLEC" business I can tell you that we typically refer to T3 > when discussing "Transport only" type ciruits of 45Mbps from point to point. > When we refer to putting services on it, such as Frame Relay, ATM, PPP, > voice (PRI, Trunks, etc) then we usually refer to them as DS3. > > However, they are certainly used interchangibly by most. > > A T1 or T3 is a "Carrier" as explained below: > > To see the relationship between T-carrier, E-carrier, and DS0 multiples, see > digital signal X. > The T-carrier system, introduced by the Bell System in the U.S. in the > 1960s, was the first successful system that supported digitized voice > transmission. The original transmission rate (1.544 Mbps) in the T-1 line is > in common use today in Internet service provider (ISP) connections to the > Internet. Another level, the T-3 line, providing 44.736 Mbps, is also > commonly used by Internet service providers. Another commonly installed > service is a fractional T-1, which is the rental of some portion of the 24 > channels in a T-1 line, with the other channels going unused. > > The T-carrier system is entirely digital, using pulse code modulation and > time-division multiplexing. The system uses four wires and provides duplex > capability (two wires for receiving and two for sending at the same time). > The T-1 digital stream consists of 24 64-Kbps channels that are multiplexed. > (The standardized 64 Kbps channel is based on the bandwidth required for a > voice conversation.) The four wires were originally a pair of twisted pair > copper wires, but can now also include coaxial cable, optical fiber, digital > microwave, and other media. A number of variations on the number and use of > channels are possible. > > In the T-1 system, voice signals are sampled 8,000 times a second and each > sample is digitized into an 8-bit word. With 24 channels being digitized at > the same time, a 192-bit frame (24 channels each with an 8-bit word) is thus > being transmitted 8,000 times a second. Each frame is separated from the > next by a single bit, making a 193-bit block. The 192 bit frame multiplied > by 8,000 and the additional 8,000 framing bits make up the T-1's 1.544 Mbps > data rate. The signaling bits are the least significant bits in each frame. > > A DS0/1/3 is a Digital signal carried by the "T" carrier as explained below: > > > Digital signal X is a term for the series of standard digital transmission > rates or levels based on DS0, a transmission rate of 64 Kbps, the bandwidth > normally used for one telephone voice channel. Both the North American > T-carrier system system and the European E-carrier systems of transmission > operate using the DS series as a base multiple. The digital signal is what > is carried inside the carrier system. > DS0 is the base for the digital signal X series. DS1, used as the signal in > the T-1 carrier, is 24 DS0 (64 Kbps) signals transmitted using pulse-code > modulation (PCM) and time-division multiplexing (TDM). DS2 is four DS1 > signals multiplexed together to produce a rate of 6.312 Mbps. DS3, the > signal in the T-3 carrier, carries a multiple of 28 DS1 signals or 672 DS0s > or 44.736 Mbps. > > Digital signal X is based on the ANSI T1.107 guidelines. The ITU-TS > guidelines differ somewhat. > > > > > > -----Original Message----- > > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of > > MADMAN > > Sent: Thursday, March 20, 2003 4:32 PM > > To: [EMAIL PROTECTED] > > Subject: Re: DS3 bandwidth issues [7:65790] > > > > > > six of one half dozen of the other, they both describe the same > > thing. I "think" T is a Bellcore name and DS is a some standards > > body name. > > > > Dave > > > > Scott Roberts wrote: > > > why do people refer to a DS3 as a DS3 and not a T3? is there > > something I'm > > > missing? > > > > > > scott > > > > > > ""Nate"" wrote in message > > > news:[EMAIL PROTECTED] > > > > > >>We've run a bandwidth test on our DS3 with nothing connected to it but a > > >>workstation (and obviously a router/pix). We went to testmyspeed.com as > > >>well as dslreports.com. We both got very good bandwidth tests (upward > > > > > > 6m/s) > > > > > >>however in transferring a 200m file to/from a workstation behind the > > >>connection, we got over 30 minutes while our existing T1 got 26 minutes. > > >>Anyone mind explaining this phenomenon? Just a side note, we have no > > >>encryption between GRE tunnels. Thanks in advanced. > > >> > > >>-Nate > > -- > > David Madland > > CCIE# 2016 > > Sr. Network Engineer > > Qwest Communications > > 612-664-3367 > > > > I would rather have a German division in front of me than a French one > > behind me." > > --- General George S. Patton Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=65941&t=65790 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
