Re: Some ISDN PRI questions
> topics in McGraw Hill BCRAN: > > > > > http://www.bookpool.com/.x/p9zwbh4yt6/sm/0072124806 > > > > > > Channelized T1/E1 frame format: 208-213 > > > Framing and linecoding: 226-228 > > > Robbed bit signaling/Channel Associated Signaling: > > 230-231 > > > > > > The purpose of this book was to go beyond the > > Ciscopress material, which > > > focuses on the BCRAN exam material only and add > > information that seems > > > to have been ignored by Ciscopress's BCRAN. You > > will note that in this > > > book, when > > > a topic is not covered on the BCRAN exam, there is > > a note indicating such, > > > so that you don't review material not required for > > the examok shameless > > > plug over... :-) > > > > > > Adam Quiggle > > > > > > At 05:31 PM 7/11/00, Ole Drews Jensen wrote: > > > >Hi Subbi, > > > > > > > >You are dragging me out in orbit now, but I'll > > try to hang on. > > > > > > > >To get back to the ISDN PRI... > > > > > > > >The 8000 samples, are you sure that it's not 8 > > k-samples (8*1024) = 8192 > > > >samples??? > > > > > > > >That would make sense since the 192 bits (24*8) > > multiplied with 8192 equals > > > >1572864 which again equals 1536 kbps > > (1572864/1024). That brings us back to > > > >24 channels where the last one is only used for > > signaling - not data. > > > > > > > >Ole > > > > > > > >~~ > > > > Ole Drews Jensen > > > > Systems Network Manager > > > > CCNA, MCSE, MCP+I > > > > RWR Enterprises, Inc. > > > > [EMAIL PROTECTED] > > > >~~ > > > > > > > >-Original Message- > > > >From: Subramanian Nallasivam > > [mailto:[EMAIL PROTECTED]] > > > >Sent: Tuesday, July 11, 2000 4:14 PM > > > >To: Ole Drews Jensen > > > >Cc: [EMAIL PROTECTED] > > > >Subject: Re: Some ISDN PRI questions > > > > > > > > > > > >Hi Ole, > > > > > > > >Let me take the case of T1. In T1 all > > the 24 channel are used for > > > >sending data. There will be one framing bit which > > constitiute to 193 bits. > > > >So > > > >193 * 8000 = 1544 kbps. And one bit from every > > sixth frame in case of > > > >superframe(which consists of 12 T1/DS1 frames) > > will be robbed for > > > >signalling. > > > >The robbed bit will be the least significant bit > > and this concept is known > > > >as > > > >robbed-bit signalling. If I am wrong then please > > correct me. > > > > > > > >Thanks, > > > >-Subbi. > > > > > > > > > > > >Ole Drews Jensen wrote: > > > > > > > > > Hi Subbi, > > > > > > > > > > That would still only leave 184 * 8000 = > > 1472000 bps or (1472000/1024) > > > > > 1437.5 kbps for data. > > > > > > > > > > Ole > > > > > > > > > > ~~ > > > > > Ole Drews Jensen > > > > > Systems Network Manager > > > > > CCNA, MCSE, MCP+I > > > > > RWR Enterprises, Inc. > > > > > [EMAIL PROTECTED] > > > > > ~~ > > > > > > > > > > -Original Message- > > >=== message truncated === > > >__ >Do You Yahoo!? >Get Yahoo! Mail Free email you can access from anywhere! >http://mail.yahoo.com/ > >___ >UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html >FAQ, list archives, and subscription info: http://www.groupstudy.com >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] *** Adam Quiggle Sr. Network Engineer BP-Amoco/MCI Worldcom CCNA, MCNE, MCSE [EMAIL PROTECTED] ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Some ISDN PRI questions
Thanks Jay, Ole ~~ Ole Drews Jensen Systems Network Manager CCNA, MCSE, MCP+I RWR Enterprises, Inc. [EMAIL PROTECTED] ~~ -Original Message- From: Jay Hennigan [mailto:[EMAIL PROTECTED]] Sent: Wednesday, July 12, 2000 12:17 AM To: Ole Drews Jensen Cc: 'Subramanian Nallasivam'; [EMAIL PROTECTED] Subject: RE: Some ISDN PRI questions On Tue, 11 Jul 2000, Ole Drews Jensen wrote: > Hi Subbi, > > You are dragging me out in orbit now, but I'll try to hang on. > > To get back to the ISDN PRI... > > The 8000 samples, are you sure that it's not 8 k-samples (8*1024) = 8192 > samples??? In the telco world, 1K = 1000. In the data world 1K = 1024. ISDN and the DS-n standards came from the telco world. :-) > That would make sense since the 192 bits (24*8) multiplied with 8192 equals > 1572864 which again equals 1536 kbps (1572864/1024). That brings us back to > 24 channels where the last one is only used for signaling - not data. 192 bits multiplied by 8000 = 1536000. Add in 8000 for framing, and you have 1544000, the clock rate for DS-1. The proper way to think or this is really: 8000 samples per second of 8 bit resolution = 64000 bits per second, which equals one channel, or one DS-0. 24 channels of 64000 bits equal 1536000 bits per second (or 192000 bytes). Plus 8000 bits per second for framing. Viola! (a stringed instrument appears mysteriously out of thin air) 1,544,000 bits per second = DS-1. -- Jay Hennigan - Network Administration - [EMAIL PROTECTED] NetLojix Communications, Inc. NASDAQ: NETX - http://www.netlojix.com/ WestNet: Connecting you to the planet. 805 884-6323 ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Some ISDN PRI questions
Hey Adam, Thanks for a long and detailed explanation. I can see in your example that the 24th (D) channel is still calculated into the data bandwidth: >Data Channels (23B+1D) >24 channels * 8 bits/sample * 8000 samples/second = 1,536,000bps That is kind of what I do not understand. However, I have your book which I must grade as excellent, but apart from chapter 10 (which I started out reading due to the fact that we currently have 10 x 700 routers for our small branch offices) I am only on page 91, so I will just leave it alone for now, and wait 3-4 days until I get to it. What I was kind of looking for in my original message, was if the D channel was used for data or only signaling, but I guess there is more to it than that. Thanks again for your reply, Ole ~~ Ole Drews Jensen Systems Network Manager CCNA, MCSE, MCP+I RWR Enterprises, Inc. [EMAIL PROTECTED] ~~ -Original Message- From: Adam Quiggle [mailto:[EMAIL PROTECTED]] Sent: Wednesday, July 12, 2000 12:11 AM To: Ole Drews Jensen; 'Subramanian Nallasivam'; Ole Drews Jensen Cc: [EMAIL PROTECTED] Subject: RE: Some ISDN PRI questions Hey Ole, It really is 8000 samples. The number 8000 comes from Nyquist's theorem which in a nutshell states that in order to properly represent an analog signal in digital form we must sample twice the frequency range. Since an analog signal is represented from 0-4Khz we must sample an analog signal (2*4000) times a second in order to transport it with minimal loss. Thus we get 8000 samples a second. Each sample is encoded with 8 bits to represent an analog signal at anyone time, thus we get: 8 bits/samples * 8000 samples/sec = 64,000 bits/sec (look familiar?) Now, if we look at a single frame of a channelized T1 we can see that we have twenty-four 8-bit timeslots plus a single bit for framing or: Data Channels (23B+1D) 24 channels * 8 bits/sample * 8000 samples/second = 1,536,000bps Framing Bit 1 bit/sample * 8000 samples/second = 8000 bps So, we can see that for data we have 1,536,000 bps and 8,000 bps for framing, which equals 1,544,000 bps. This is why people think of a T1 as 1.544Mb but it's true throughput is only 1.536Mb. So, what is the framing bit used for? Framing allows the CSU/DSU to find the timeslots in the channelized T1. Remember, that 8000 T1 frames are flying out of the circuit every second, and the CSU/DSU must know how to find the T1 frames in this circuit (don't ask me why, but I can't stop thinking of Lucille Ball in the bon/bon episode :-) In order to maintain sync, the CSU/DSU must grab every 193rd bit off of the line, string them together and see if it forms the "pattern" it is looking for. The type of framing used describes the pattern to look for. When using Superframing twelve of these bits are strung together and must form the following pattern of "100011011100". If it doesn't form this pattern, the CSU/DSU is said to slip and it must then resync its timing to the signal. Extended Superframing is an extension of Superframing and instead of trying to collect twelve of these framing bits, it collects 24 of these bits for syncing to the signal. So, what about robbed bit signaling (RBS)? RBS is not a function of what type of framing you are using. RBS also known as Channel Associated Signaling (CAS) is a technique in which supervisory and signaling information is sent by removing the 8th bit of the 6th and 12th Superframe or the 8th bit of the 6th, 12th, 18th and 24th bit of the extended superframe. The overall affect for those using Channel Associated Signaling is that you don't need a D channel, however all your B channels use 56kbps. You can find more information on the following topics in McGraw Hill BCRAN: http://www.bookpool.com/.x/p9zwbh4yt6/sm/0072124806 Channelized T1/E1 frame format: 208-213 Framing and linecoding: 226-228 Robbed bit signaling/Channel Associated Signaling: 230-231 The purpose of this book was to go beyond the Ciscopress material, which focuses on the BCRAN exam material only and add information that seems to have been ignored by Ciscopress's BCRAN. You will note that in this book, when a topic is not covered on the BCRAN exam, there is a note indicating such, so that you don't review material not required for the examok shameless plug over... :-) Adam Quiggle At 05:31 PM 7/11/00, Ole Drews Jensen wrote: >Hi Subbi, > >You are dragging me out in orbit now, but I'll try to hang on. > >To get back to the ISDN PRI... > >The 8000 samples, are you sure that it's not 8 k-samples (8*1024) = 8192 >samples??? > >That would make sense since the 192 bits (24*8) multiplied with 8192 equals >1572864 which again equals 1536 kbps (1572864/1024). That brings us back to >24 channels where the last one is only used for signaling - not data. > >Ole >
Re: Some ISDN PRI questions
Adam, If the 6th, 12th, 18th and 24th bit of the extended superframe are robbed, does this mean the data part of a T1 will be 20x64k+4x56k=1504K(1.504M) in stead of 1.536M? Hope I am not missing something here. Thanks Kent --- Subramanian Nallasivam <[EMAIL PROTECTED]> wrote: > Hi Adam, > > Thanks for your clarification . I am having one > more doubt. Where comes the > concept of red and yellow alaram. > > Thanks, > -Subbi. > > Adam Quiggle wrote: > > > Hey Ole, > > > > It really is 8000 samples. The number 8000 comes > from Nyquist's > > theorem which in a nutshell states that in order > to properly represent > > an analog signal in digital form we must sample > twice the frequency > > range. Since an analog signal is represented from > 0-4Khz we must sample > > an analog signal (2*4000) times a second in order > to transport it with > > minimal loss. Thus we get 8000 samples a second. > Each sample is encoded > > with 8 bits to represent an analog signal at > anyone time, thus we get: > > > > 8 bits/samples * 8000 samples/sec = 64,000 > bits/sec (look familiar?) > > > > Now, if we look at a single frame of a channelized > T1 we can see that > > we have twenty-four 8-bit timeslots plus a single > bit for framing or: > > > > Data Channels (23B+1D) > > 24 channels * 8 bits/sample * 8000 samples/second > = 1,536,000bps > > > > Framing Bit > > 1 bit/sample * 8000 samples/second = 8000 bps > > > > So, we can see that for data we have 1,536,000 bps > and 8,000 bps for framing, > > which equals 1,544,000 bps. This is why people > think of a T1 as 1.544Mb > > but it's true throughput is only 1.536Mb. > > > > So, what is the framing bit used for? Framing > allows the CSU/DSU to find > > the timeslots in the channelized T1. Remember, > that 8000 T1 frames are > > flying out of the circuit every second, and the > CSU/DSU must know how > > to find the T1 frames in this circuit (don't ask > me why, but I can't stop > > thinking of Lucille Ball in the bon/bon episode > :-) > > > > In order to maintain sync, the CSU/DSU must grab > every 193rd bit off of > > the line, string them together and see if it forms > the "pattern" it is looking > > for. The type of framing used describes the > pattern to look for. > > > > When using Superframing twelve of these bits are > strung together and must > > form the following pattern of "100011011100". If > it doesn't form this > > pattern, the CSU/DSU is said to slip and it must > then resync its > > timing to the signal. > > > > Extended Superframing is an extension of > Superframing and instead of > > trying to collect twelve of these framing bits, it > collects 24 of these > > bits for syncing to the signal. > > > > So, what about robbed bit signaling (RBS)? RBS is > not a function of > > what type of framing you are using. RBS also > known as Channel Associated > > Signaling (CAS) is a technique in which > supervisory and signaling information > > is sent by removing the 8th bit of the 6th and > 12th Superframe or the > > 8th bit of the 6th, 12th, 18th and 24th bit of the > extended superframe. > > > > The overall affect for those using Channel > Associated Signaling is that you > > don't need a D channel, however all your B > channels use 56kbps. > > > > You can find more information on the following > topics in McGraw Hill BCRAN: > > > http://www.bookpool.com/.x/p9zwbh4yt6/sm/0072124806 > > > > Channelized T1/E1 frame format: 208-213 > > Framing and linecoding: 226-228 > > Robbed bit signaling/Channel Associated Signaling: > 230-231 > > > > The purpose of this book was to go beyond the > Ciscopress material, which > > focuses on the BCRAN exam material only and add > information that seems > > to have been ignored by Ciscopress's BCRAN. You > will note that in this > > book, when > > a topic is not covered on the BCRAN exam, there is > a note indicating such, > > so that you don't review material not required for > the examok shameless > > plug over... :-) > > > > Adam Quiggle > > > > At 05:31 PM 7/11/00, Ole Drews Jensen wrote: > > >Hi Subbi, > > > > > >You are dragging me out in orbit now, but I'll > try to hang on. > > > > > >To get back to the ISDN PRI... > > > > > >The 8000 samples, are you sure that it's not 8 > k-samples
Re: Some ISDN PRI questions
Hi Adam, Thanks for your clarification . I am having one more doubt. Where comes the concept of red and yellow alaram. Thanks, -Subbi. Adam Quiggle wrote: > Hey Ole, > > It really is 8000 samples. The number 8000 comes from Nyquist's > theorem which in a nutshell states that in order to properly represent > an analog signal in digital form we must sample twice the frequency > range. Since an analog signal is represented from 0-4Khz we must sample > an analog signal (2*4000) times a second in order to transport it with > minimal loss. Thus we get 8000 samples a second. Each sample is encoded > with 8 bits to represent an analog signal at anyone time, thus we get: > > 8 bits/samples * 8000 samples/sec = 64,000 bits/sec (look familiar?) > > Now, if we look at a single frame of a channelized T1 we can see that > we have twenty-four 8-bit timeslots plus a single bit for framing or: > > Data Channels (23B+1D) > 24 channels * 8 bits/sample * 8000 samples/second = 1,536,000bps > > Framing Bit > 1 bit/sample * 8000 samples/second = 8000 bps > > So, we can see that for data we have 1,536,000 bps and 8,000 bps for framing, > which equals 1,544,000 bps. This is why people think of a T1 as 1.544Mb > but it's true throughput is only 1.536Mb. > > So, what is the framing bit used for? Framing allows the CSU/DSU to find > the timeslots in the channelized T1. Remember, that 8000 T1 frames are > flying out of the circuit every second, and the CSU/DSU must know how > to find the T1 frames in this circuit (don't ask me why, but I can't stop > thinking of Lucille Ball in the bon/bon episode :-) > > In order to maintain sync, the CSU/DSU must grab every 193rd bit off of > the line, string them together and see if it forms the "pattern" it is looking > for. The type of framing used describes the pattern to look for. > > When using Superframing twelve of these bits are strung together and must > form the following pattern of "100011011100". If it doesn't form this > pattern, the CSU/DSU is said to slip and it must then resync its > timing to the signal. > > Extended Superframing is an extension of Superframing and instead of > trying to collect twelve of these framing bits, it collects 24 of these > bits for syncing to the signal. > > So, what about robbed bit signaling (RBS)? RBS is not a function of > what type of framing you are using. RBS also known as Channel Associated > Signaling (CAS) is a technique in which supervisory and signaling information > is sent by removing the 8th bit of the 6th and 12th Superframe or the > 8th bit of the 6th, 12th, 18th and 24th bit of the extended superframe. > > The overall affect for those using Channel Associated Signaling is that you > don't need a D channel, however all your B channels use 56kbps. > > You can find more information on the following topics in McGraw Hill BCRAN: > http://www.bookpool.com/.x/p9zwbh4yt6/sm/0072124806 > > Channelized T1/E1 frame format: 208-213 > Framing and linecoding: 226-228 > Robbed bit signaling/Channel Associated Signaling: 230-231 > > The purpose of this book was to go beyond the Ciscopress material, which > focuses on the BCRAN exam material only and add information that seems > to have been ignored by Ciscopress's BCRAN. You will note that in this > book, when > a topic is not covered on the BCRAN exam, there is a note indicating such, > so that you don't review material not required for the examok shameless > plug over... :-) > > Adam Quiggle > > At 05:31 PM 7/11/00, Ole Drews Jensen wrote: > >Hi Subbi, > > > >You are dragging me out in orbit now, but I'll try to hang on. > > > >To get back to the ISDN PRI... > > > >The 8000 samples, are you sure that it's not 8 k-samples (8*1024) = 8192 > >samples??? > > > >That would make sense since the 192 bits (24*8) multiplied with 8192 equals > >1572864 which again equals 1536 kbps (1572864/1024). That brings us back to > >24 channels where the last one is only used for signaling - not data. > > > >Ole > > > >~~~~~~~~~~ > > Ole Drews Jensen > > Systems Network Manager > > CCNA, MCSE, MCP+I > > RWR Enterprises, Inc. > > [EMAIL PROTECTED] > >~~ > > > >-Original Message- > >From: Subramanian Nallasivam [mailto:[EMAIL PROTECTED]] > >Sent: Tuesday, July 11, 2000 4:14 PM > >To: Ole Drews Jensen > >Cc: [EMAIL PROTECTED] > >Subject: Re: Some ISDN PRI questions > > > > > >Hi Ole, > > > >Let me take the case of T1. In T1 all the 24 channel are used for &
RE: Some ISDN PRI questions
On Tue, 11 Jul 2000, Ole Drews Jensen wrote: > Hi Subbi, > > You are dragging me out in orbit now, but I'll try to hang on. > > To get back to the ISDN PRI... > > The 8000 samples, are you sure that it's not 8 k-samples (8*1024) = 8192 > samples??? In the telco world, 1K = 1000. In the data world 1K = 1024. ISDN and the DS-n standards came from the telco world. :-) > That would make sense since the 192 bits (24*8) multiplied with 8192 equals > 1572864 which again equals 1536 kbps (1572864/1024). That brings us back to > 24 channels where the last one is only used for signaling - not data. 192 bits multiplied by 8000 = 1536000. Add in 8000 for framing, and you have 1544000, the clock rate for DS-1. The proper way to think or this is really: 8000 samples per second of 8 bit resolution = 64000 bits per second, which equals one channel, or one DS-0. 24 channels of 64000 bits equal 1536000 bits per second (or 192000 bytes). Plus 8000 bits per second for framing. Viola! (a stringed instrument appears mysteriously out of thin air) 1,544,000 bits per second = DS-1. -- Jay Hennigan - Network Administration - [EMAIL PROTECTED] NetLojix Communications, Inc. NASDAQ: NETX - http://www.netlojix.com/ WestNet: Connecting you to the planet. 805 884-6323 ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Some ISDN PRI questions
Hey Ole, It really is 8000 samples. The number 8000 comes from Nyquist's theorem which in a nutshell states that in order to properly represent an analog signal in digital form we must sample twice the frequency range. Since an analog signal is represented from 0-4Khz we must sample an analog signal (2*4000) times a second in order to transport it with minimal loss. Thus we get 8000 samples a second. Each sample is encoded with 8 bits to represent an analog signal at anyone time, thus we get: 8 bits/samples * 8000 samples/sec = 64,000 bits/sec (look familiar?) Now, if we look at a single frame of a channelized T1 we can see that we have twenty-four 8-bit timeslots plus a single bit for framing or: Data Channels (23B+1D) 24 channels * 8 bits/sample * 8000 samples/second = 1,536,000bps Framing Bit 1 bit/sample * 8000 samples/second = 8000 bps So, we can see that for data we have 1,536,000 bps and 8,000 bps for framing, which equals 1,544,000 bps. This is why people think of a T1 as 1.544Mb but it's true throughput is only 1.536Mb. So, what is the framing bit used for? Framing allows the CSU/DSU to find the timeslots in the channelized T1. Remember, that 8000 T1 frames are flying out of the circuit every second, and the CSU/DSU must know how to find the T1 frames in this circuit (don't ask me why, but I can't stop thinking of Lucille Ball in the bon/bon episode :-) In order to maintain sync, the CSU/DSU must grab every 193rd bit off of the line, string them together and see if it forms the "pattern" it is looking for. The type of framing used describes the pattern to look for. When using Superframing twelve of these bits are strung together and must form the following pattern of "100011011100". If it doesn't form this pattern, the CSU/DSU is said to slip and it must then resync its timing to the signal. Extended Superframing is an extension of Superframing and instead of trying to collect twelve of these framing bits, it collects 24 of these bits for syncing to the signal. So, what about robbed bit signaling (RBS)? RBS is not a function of what type of framing you are using. RBS also known as Channel Associated Signaling (CAS) is a technique in which supervisory and signaling information is sent by removing the 8th bit of the 6th and 12th Superframe or the 8th bit of the 6th, 12th, 18th and 24th bit of the extended superframe. The overall affect for those using Channel Associated Signaling is that you don't need a D channel, however all your B channels use 56kbps. You can find more information on the following topics in McGraw Hill BCRAN: http://www.bookpool.com/.x/p9zwbh4yt6/sm/0072124806 Channelized T1/E1 frame format: 208-213 Framing and linecoding: 226-228 Robbed bit signaling/Channel Associated Signaling: 230-231 The purpose of this book was to go beyond the Ciscopress material, which focuses on the BCRAN exam material only and add information that seems to have been ignored by Ciscopress's BCRAN. You will note that in this book, when a topic is not covered on the BCRAN exam, there is a note indicating such, so that you don't review material not required for the examok shameless plug over... :-) Adam Quiggle At 05:31 PM 7/11/00, Ole Drews Jensen wrote: >Hi Subbi, > >You are dragging me out in orbit now, but I'll try to hang on. > >To get back to the ISDN PRI... > >The 8000 samples, are you sure that it's not 8 k-samples (8*1024) = 8192 >samples??? > >That would make sense since the 192 bits (24*8) multiplied with 8192 equals >1572864 which again equals 1536 kbps (1572864/1024). That brings us back to >24 channels where the last one is only used for signaling - not data. > >Ole > >~~ > Ole Drews Jensen > Systems Network Manager > CCNA, MCSE, MCP+I > RWR Enterprises, Inc. > [EMAIL PROTECTED] >~~ > >-Original Message- >From: Subramanian Nallasivam [mailto:[EMAIL PROTECTED]] >Sent: Tuesday, July 11, 2000 4:14 PM >To: Ole Drews Jensen >Cc: [EMAIL PROTECTED] >Subject: Re: Some ISDN PRI questions > > >Hi Ole, > >Let me take the case of T1. In T1 all the 24 channel are used for >sending data. There will be one framing bit which constitiute to 193 bits. >So >193 * 8000 = 1544 kbps. And one bit from every sixth frame in case of >superframe(which consists of 12 T1/DS1 frames) will be robbed for >signalling. >The robbed bit will be the least significant bit and this concept is known >as >robbed-bit signalling. If I am wrong then please correct me. > >Thanks, >-Subbi. > > >Ole Drews Jensen wrote: > > > Hi Subbi, > > > > That would still only leave 184 * 8000 = 1472000 bps or (1472000/1024) > > 1437.5 kbps for data. > > > > Ole > > > > ~
Re: Some ISDN PRI questions
Hi Ole, Let me take the case of T1. In T1 all the 24 channel are used for sending data. There will be one framing bit which constitiute to 193 bits. So 193 * 8000 = 1544 kbps. And one bit from every sixth frame in case of superframe(which consists of 12 T1/DS1 frames) will be robbed for signalling. The robbed bit will be the least significant bit and this concept is known as robbed-bit signalling. If I am wrong then please correct me. Thanks, -Subbi. Ole Drews Jensen wrote: > Hi Subbi, > > That would still only leave 184 * 8000 = 1472000 bps or (1472000/1024) > 1437.5 kbps for data. > > Ole > > ~~ > Ole Drews Jensen > Systems Network Manager > CCNA, MCSE, MCP+I > RWR Enterprises, Inc. > [EMAIL PROTECTED] > ~~ > > -Original Message- > From: Subramanian Nallasivam [mailto:[EMAIL PROTECTED]] > Sent: Tuesday, July 11, 2000 3:54 PM > To: Ole Drews Jensen > Cc: [EMAIL PROTECTED] > Subject: Re: Some ISDN PRI questions > > Hi, > > I am new to ISDN concepts, but here they are > > We have 23 DSO for carrying data. Each channel carries 8 bit word or > something. So > > 23 * 8 = 184 > >One channel is used for carrying signal . So the number comes out to be > >184 + 8 = 192 > > Since 8000 samples are sampled per second , the calculation comes to be > > 192 * 8000 = 1536 Kbps. > > T1 uses in-band signalling ( uses same data channel for signalling also) > where > as ISDN PRI uses out-band signalling (uses seperate channels for signals). > > I am new to ISDN cocepts. If I am wrong please correct me. > > Thanks, > -Subbi. > > Ole Drews Jensen wrote: > > > The ISDN BRI has two 64 kbps B channels and one 16 kbps D channel. That > > gives us a maximum of 128 kbps bandwidth for data which makes sense. > > > > The ISDN PRI has twenty three 64 kbps B channels and one 64 kbps D > channel. > > That should give us a maximum of 1472 kbps bandwidth for data, and not > 1536 > > kbps as normally specified unless it is possible to use the D channel for > > data too ??? > > > > The ISDN PRI in Europe has thirty 64 kbps B channels and one 64 kbps D > > channel. That should give us a maximum of 1920 kbps for data, and not 2048 > > kbps as normally specified even if the D channel is used for data too. > > > > Are these numbers just used because it's easier to remember the 1536 and > > 2048 values, or is there a hidden factor here??? > > > > A last question: I sometimes hear people refer to an ISDN PRI as a T1. The > > T1 has the same amount of channels and bandwidth, so the question is - are > > there really a big difference between these two specifications, or is it > > more or less the same??? > > > > Some or all of these questions might be answered later on in my book, but > I > > can't wait any longer - I want to know NOW :-) > > > > Thanks for any comments on this. > > > > Ole > > > > ~~ > > Ole Drews Jensen > > Systems Network Manager > > CCNA, MCSE, MCP+I > > RWR Enterprises, Inc. > > [EMAIL PROTECTED] > > ~~ > > > > ___ > > UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html > > FAQ, list archives, and subscription info: http://www.groupstudy.com > > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Some ISDN PRI questions
Hi Subbi, You are dragging me out in orbit now, but I'll try to hang on. To get back to the ISDN PRI... The 8000 samples, are you sure that it's not 8 k-samples (8*1024) = 8192 samples??? That would make sense since the 192 bits (24*8) multiplied with 8192 equals 1572864 which again equals 1536 kbps (1572864/1024). That brings us back to 24 channels where the last one is only used for signaling - not data. Ole ~~ Ole Drews Jensen Systems Network Manager CCNA, MCSE, MCP+I RWR Enterprises, Inc. [EMAIL PROTECTED] ~~ -Original Message- From: Subramanian Nallasivam [mailto:[EMAIL PROTECTED]] Sent: Tuesday, July 11, 2000 4:14 PM To: Ole Drews Jensen Cc: [EMAIL PROTECTED] Subject: Re: Some ISDN PRI questions Hi Ole, Let me take the case of T1. In T1 all the 24 channel are used for sending data. There will be one framing bit which constitiute to 193 bits. So 193 * 8000 = 1544 kbps. And one bit from every sixth frame in case of superframe(which consists of 12 T1/DS1 frames) will be robbed for signalling. The robbed bit will be the least significant bit and this concept is known as robbed-bit signalling. If I am wrong then please correct me. Thanks, -Subbi. Ole Drews Jensen wrote: > Hi Subbi, > > That would still only leave 184 * 8000 = 1472000 bps or (1472000/1024) > 1437.5 kbps for data. > > Ole > > ~~ > Ole Drews Jensen > Systems Network Manager > CCNA, MCSE, MCP+I > RWR Enterprises, Inc. > [EMAIL PROTECTED] > ~~ > > -Original Message- > From: Subramanian Nallasivam [mailto:[EMAIL PROTECTED]] > Sent: Tuesday, July 11, 2000 3:54 PM > To: Ole Drews Jensen > Cc: [EMAIL PROTECTED] > Subject: Re: Some ISDN PRI questions > > Hi, > > I am new to ISDN concepts, but here they are > > We have 23 DSO for carrying data. Each channel carries 8 bit word or > something. So > > 23 * 8 = 184 > >One channel is used for carrying signal . So the number comes out to be > >184 + 8 = 192 > > Since 8000 samples are sampled per second , the calculation comes to be > > 192 * 8000 = 1536 Kbps. > > T1 uses in-band signalling ( uses same data channel for signalling also) > where > as ISDN PRI uses out-band signalling (uses seperate channels for signals). > > I am new to ISDN cocepts. If I am wrong please correct me. > > Thanks, > -Subbi. > > Ole Drews Jensen wrote: > > > The ISDN BRI has two 64 kbps B channels and one 16 kbps D channel. That > > gives us a maximum of 128 kbps bandwidth for data which makes sense. > > > > The ISDN PRI has twenty three 64 kbps B channels and one 64 kbps D > channel. > > That should give us a maximum of 1472 kbps bandwidth for data, and not > 1536 > > kbps as normally specified unless it is possible to use the D channel for > > data too ??? > > > > The ISDN PRI in Europe has thirty 64 kbps B channels and one 64 kbps D > > channel. That should give us a maximum of 1920 kbps for data, and not 2048 > > kbps as normally specified even if the D channel is used for data too. > > > > Are these numbers just used because it's easier to remember the 1536 and > > 2048 values, or is there a hidden factor here??? > > > > A last question: I sometimes hear people refer to an ISDN PRI as a T1. The > > T1 has the same amount of channels and bandwidth, so the question is - are > > there really a big difference between these two specifications, or is it > > more or less the same??? > > > > Some or all of these questions might be answered later on in my book, but > I > > can't wait any longer - I want to know NOW :-) > > > > Thanks for any comments on this. > > > > Ole > > > > ~~ > > Ole Drews Jensen > > Systems Network Manager > > CCNA, MCSE, MCP+I > > RWR Enterprises, Inc. > > [EMAIL PROTECTED] > > ~~ > > > > ___ > > UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html > > FAQ, list archives, and subscription info: http://www.groupstudy.com > > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Some ISDN PRI questions
Hi Subbi, That would still only leave 184 * 8000 = 1472000 bps or (1472000/1024) 1437.5 kbps for data. Ole ~~ Ole Drews Jensen Systems Network Manager CCNA, MCSE, MCP+I RWR Enterprises, Inc. [EMAIL PROTECTED] ~~ -Original Message- From: Subramanian Nallasivam [mailto:[EMAIL PROTECTED]] Sent: Tuesday, July 11, 2000 3:54 PM To: Ole Drews Jensen Cc: [EMAIL PROTECTED] Subject: Re: Some ISDN PRI questions Hi, I am new to ISDN concepts, but here they are We have 23 DSO for carrying data. Each channel carries 8 bit word or something. So 23 * 8 = 184 One channel is used for carrying signal . So the number comes out to be 184 + 8 = 192 Since 8000 samples are sampled per second , the calculation comes to be 192 * 8000 = 1536 Kbps. T1 uses in-band signalling ( uses same data channel for signalling also) where as ISDN PRI uses out-band signalling (uses seperate channels for signals). I am new to ISDN cocepts. If I am wrong please correct me. Thanks, -Subbi. Ole Drews Jensen wrote: > The ISDN BRI has two 64 kbps B channels and one 16 kbps D channel. That > gives us a maximum of 128 kbps bandwidth for data which makes sense. > > The ISDN PRI has twenty three 64 kbps B channels and one 64 kbps D channel. > That should give us a maximum of 1472 kbps bandwidth for data, and not 1536 > kbps as normally specified unless it is possible to use the D channel for > data too ??? > > The ISDN PRI in Europe has thirty 64 kbps B channels and one 64 kbps D > channel. That should give us a maximum of 1920 kbps for data, and not 2048 > kbps as normally specified even if the D channel is used for data too. > > Are these numbers just used because it's easier to remember the 1536 and > 2048 values, or is there a hidden factor here??? > > A last question: I sometimes hear people refer to an ISDN PRI as a T1. The > T1 has the same amount of channels and bandwidth, so the question is - are > there really a big difference between these two specifications, or is it > more or less the same??? > > Some or all of these questions might be answered later on in my book, but I > can't wait any longer - I want to know NOW :-) > > Thanks for any comments on this. > > Ole > > ~~ > Ole Drews Jensen > Systems Network Manager > CCNA, MCSE, MCP+I > RWR Enterprises, Inc. > [EMAIL PROTECTED] > ~~ > > ___ > UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html > FAQ, list archives, and subscription info: http://www.groupstudy.com > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Some ISDN PRI questions
Hi, I am new to ISDN concepts, but here they are We have 23 DSO for carrying data. Each channel carries 8 bit word or something. So 23 * 8 = 184 One channel is used for carrying signal . So the number comes out to be 184 + 8 = 192 Since 8000 samples are sampled per second , the calculation comes to be 192 * 8000 = 1536 Kbps. T1 uses in-band signalling ( uses same data channel for signalling also) where as ISDN PRI uses out-band signalling (uses seperate channels for signals). I am new to ISDN cocepts. If I am wrong please correct me. Thanks, -Subbi. Ole Drews Jensen wrote: > The ISDN BRI has two 64 kbps B channels and one 16 kbps D channel. That > gives us a maximum of 128 kbps bandwidth for data which makes sense. > > The ISDN PRI has twenty three 64 kbps B channels and one 64 kbps D channel. > That should give us a maximum of 1472 kbps bandwidth for data, and not 1536 > kbps as normally specified unless it is possible to use the D channel for > data too ??? > > The ISDN PRI in Europe has thirty 64 kbps B channels and one 64 kbps D > channel. That should give us a maximum of 1920 kbps for data, and not 2048 > kbps as normally specified even if the D channel is used for data too. > > Are these numbers just used because it's easier to remember the 1536 and > 2048 values, or is there a hidden factor here??? > > A last question: I sometimes hear people refer to an ISDN PRI as a T1. The > T1 has the same amount of channels and bandwidth, so the question is - are > there really a big difference between these two specifications, or is it > more or less the same??? > > Some or all of these questions might be answered later on in my book, but I > can't wait any longer - I want to know NOW :-) > > Thanks for any comments on this. > > Ole > > ~~ > Ole Drews Jensen > Systems Network Manager > CCNA, MCSE, MCP+I > RWR Enterprises, Inc. > [EMAIL PROTECTED] > ~~ > > ___ > UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html > FAQ, list archives, and subscription info: http://www.groupstudy.com > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] ___ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
