Re: Confusion: Channelized and Unchannelized T1 [7:47844]
John, There's nothing wrong with your understanding of channelized vs. unchannelized. I believe your provider's tech dosen't understand or is completely mis-informed. Nigel - Original Message - From: "John Neiberger" To: Sent: Monday, July 01, 2002 12:10 PM Subject: Confusion: Channelized and Unchannelized T1 [7:47844] > Just when I thought I understood the T1 world pretty well we've run into > a situation that is thoroughly confusing me. > > I was under the impression that channelized T1 services used 24 > timeslots. I call that 'channelized' because it has 24 distinct > 'channels'. It's my understanding that unchannelized T1 doesn't use the > 24 timeslots and instead sends one giant 192-bit frame. > > At one of our locations we are muxing voice and data traffic onto a > single T1. At each end we split off certain channels to a router and > other channels over to the PBX. To do this, wouldn't the T1 *have* to > be channelized, since we're separating the channels at the CSU/DSU? > According to our provider, that circuit is unchannelized. If a circuit > is truly unchannelized, how would the CSU/DSU be able to accurately > split the T1 into two separate streams based on channel information? > > To be more clear, let's say we have the CSU/DSU configured to split > channels 1-12 to the router and 13-24 to the PBX. This splitting > function is based on the assumption that channels exist on the incoming > T1. If they don't exist and we have one giant frame instead of 24 > smaller frames, how could this possibly be working?? > > Yowza...my head hurts. > > John Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=47887&t=47844 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Confusion: Channelized and Unchannelized T1 [7:47844]
I think a channelized T1 sends 193 bit frames as well. 8 for each channel plus 1 for timing = 193. All T1's are channelized, otherwise it would have to be some sort of byte-synch communication, which isn't plausible. I think the tech you spoke to is incorrect as well. ""John Neiberger"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > Just when I thought I understood the T1 world pretty well we've run into > a situation that is thoroughly confusing me. > > I was under the impression that channelized T1 services used 24 > timeslots. I call that 'channelized' because it has 24 distinct > 'channels'. It's my understanding that unchannelized T1 doesn't use the > 24 timeslots and instead sends one giant 192-bit frame. > > At one of our locations we are muxing voice and data traffic onto a > single T1. At each end we split off certain channels to a router and > other channels over to the PBX. To do this, wouldn't the T1 *have* to > be channelized, since we're separating the channels at the CSU/DSU? > According to our provider, that circuit is unchannelized. If a circuit > is truly unchannelized, how would the CSU/DSU be able to accurately > split the T1 into two separate streams based on channel information? > > To be more clear, let's say we have the CSU/DSU configured to split > channels 1-12 to the router and 13-24 to the PBX. This splitting > function is based on the assumption that channels exist on the incoming > T1. If they don't exist and we have one giant frame instead of 24 > smaller frames, how could this possibly be working?? > > Yowza...my head hurts. > > John Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=47888&t=47844 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Confusion: Channelized and Unchannelized T1 [7:47844]
I think the main thing to note about cT1s is bit robbed signalling i.e channel asscociated signalling normally used to transport voice. Therefore, we've got 7 bits of payload, 1 bit for signalling for every timeslot and 1 bit for framing. Bit robbed signalling would effectively yield a 56 kbps pipe as opposed to 64 kbps offered by ISDN PRI. However, 64 kbps (1 timeslot) of the 24 timeslots is used for signalling. This is also known as common channel signalling. As I understand it, there are three major types of services riding on T1 links: 1. Pure data T1 i.e. unchannelized T1 2. Channelized T1 and 3. ISDN PRI Wes ""Steven A. Ridder"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > I think a channelized T1 sends 193 bit frames as well. 8 for each channel > plus 1 for timing = 193. > > All T1's are channelized, otherwise it would have to be some sort of > byte-synch communication, which isn't plausible. > > I think the tech you spoke to is incorrect as well. > > > ""John Neiberger"" wrote in message > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > Just when I thought I understood the T1 world pretty well we've run into > > a situation that is thoroughly confusing me. > > > > I was under the impression that channelized T1 services used 24 > > timeslots. I call that 'channelized' because it has 24 distinct > > 'channels'. It's my understanding that unchannelized T1 doesn't use the > > 24 timeslots and instead sends one giant 192-bit frame. > > > > At one of our locations we are muxing voice and data traffic onto a > > single T1. At each end we split off certain channels to a router and > > other channels over to the PBX. To do this, wouldn't the T1 *have* to > > be channelized, since we're separating the channels at the CSU/DSU? > > According to our provider, that circuit is unchannelized. If a circuit > > is truly unchannelized, how would the CSU/DSU be able to accurately > > split the T1 into two separate streams based on channel information? > > > > To be more clear, let's say we have the CSU/DSU configured to split > > channels 1-12 to the router and 13-24 to the PBX. This splitting > > function is based on the assumption that channels exist on the incoming > > T1. If they don't exist and we have one giant frame instead of 24 > > smaller frames, how could this possibly be working?? > > > > Yowza...my head hurts. > > > > John Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=47922&t=47844 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Confusion: Channelized and Unchannelized T1 [7:47844]
I think even a "pure data" T1 is channelized. Even the PRI is as well. -- RFC 1149 Compliant. ""Wesley"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > I think the main thing to note about cT1s is bit robbed signalling i.e > channel asscociated signalling normally used to transport voice. Therefore, > we've got 7 bits of payload, 1 bit for signalling for every timeslot and 1 > bit for framing. Bit robbed signalling would effectively yield a 56 kbps > pipe as opposed to 64 kbps offered by ISDN PRI. However, 64 kbps (1 > timeslot) of the 24 timeslots is used for signalling. This is also known as > common channel signalling. As I understand it, there are three major types > of services riding on T1 links: > > 1. Pure data T1 i.e. unchannelized T1 > 2. Channelized T1 and > 3. ISDN PRI > > Wes > > > ""Steven A. Ridder"" wrote in message > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > I think a channelized T1 sends 193 bit frames as well. 8 for each channel > > plus 1 for timing = 193. > > > > All T1's are channelized, otherwise it would have to be some sort of > > byte-synch communication, which isn't plausible. > > > > I think the tech you spoke to is incorrect as well. > > > > > > ""John Neiberger"" wrote in message > > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > > Just when I thought I understood the T1 world pretty well we've run into > > > a situation that is thoroughly confusing me. > > > > > > I was under the impression that channelized T1 services used 24 > > > timeslots. I call that 'channelized' because it has 24 distinct > > > 'channels'. It's my understanding that unchannelized T1 doesn't use the > > > 24 timeslots and instead sends one giant 192-bit frame. > > > > > > At one of our locations we are muxing voice and data traffic onto a > > > single T1. At each end we split off certain channels to a router and > > > other channels over to the PBX. To do this, wouldn't the T1 *have* to > > > be channelized, since we're separating the channels at the CSU/DSU? > > > According to our provider, that circuit is unchannelized. If a circuit > > > is truly unchannelized, how would the CSU/DSU be able to accurately > > > split the T1 into two separate streams based on channel information? > > > > > > To be more clear, let's say we have the CSU/DSU configured to split > > > channels 1-12 to the router and 13-24 to the PBX. This splitting > > > function is based on the assumption that channels exist on the incoming > > > T1. If they don't exist and we have one giant frame instead of 24 > > > smaller frames, how could this possibly be working?? > > > > > > Yowza...my head hurts. > > > > > > John Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=47927&t=47844 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Confusion: Channelized and Unchannelized T1 [7:47844]
Hi John Thought I would just add a few words from 'T1 A survival guide' from O'Reilly. T1 = DS1 delivered over a 4 wire copper interface DS1 = Digital Stream level 1 - 24 DS0's combined into a DS1 which supplies 1536 kbps connectivity plus 8 kbps framing and signalling overhead for a total of 1544kbps. DS0 = A single 64kbps channel. p149 - "Each time slot in the T1 has the capacity to support one traditional telephone call. Channelised T1 does exactly this - each of the 24 time slots can be treated as a digital telephone line. Each line has a 64kbps raw capacity, but since a byte must be used for signalling the maximum thoughput of a cT1 channel is 56kbps. On ther otherhand unchannelised T1 simply views each time slot as the opporunity to send another 8bits of data to the remote end and the enite capacity is one big pipe." p163 - Configuring cT1...Individual DS0's may be configured for different purposes. Some may be used for voice, some for data and different time slots may use different types of signalling. The book itself concentrates on unchannelised T1 and has been a great help to me over the past months working in the States, since in Europe we have simple E1 Regards MFC Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=47928&t=47844 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Confusion: Channelized and Unchannelized T1 [7:47844]
Hey Matt, That's exactly where I got my info from. BTW, that's a really good book to learn about T1, unchannelized or otherwise. And it goes into HDLC, PPP and Frame Relay as well. The reindeer on the front cover rocks! hehe Wes ""Matthew Crane"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > Hi John > > Thought I would just add a few words from 'T1 A survival guide' from > O'Reilly. > > T1 = DS1 delivered over a 4 wire copper interface > DS1 = Digital Stream level 1 - 24 DS0's combined into a DS1 which supplies > 1536 kbps connectivity plus 8 kbps framing and signalling overhead for a > total of 1544kbps. > DS0 = A single 64kbps channel. > > p149 - "Each time slot in the T1 has the capacity to support one traditional > telephone call. Channelised T1 does exactly this - each of the 24 time slots > can be treated as a digital telephone line. Each line has a 64kbps raw > capacity, but since a byte must be used for signalling the maximum thoughput > of a cT1 channel is 56kbps. On ther otherhand unchannelised T1 simply views > each time slot as the opporunity to send another 8bits of data to the remote > end and the enite capacity is one big pipe." > > p163 - Configuring cT1...Individual DS0's may be configured for different > purposes. Some may be used for voice, some for data and different time slots > may use different types of signalling. > > The book itself concentrates on unchannelised T1 and has been a great help > to me over the past months working in the States, since in Europe we have > simple E1 > > Regards > > MFC Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=47953&t=47844 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
