My take on it is... its out-of-band. It's just multiple logical channels multiplexed onto a single physical channel. It doesn't matter that the logical channels work together, the time slots remain dedicated to their respective channels and the traffic doesn't mix.
Just my .02 Karen *********** REPLY SEPARATOR *********** On 3/11/2003 at 11:37 PM Priscilla Oppenheimer wrote: >So, here's a question for you all. I saw this on a practice test. Does >ISDN >use "in-band" or "out-of-band" signaling and is it different for BRI versus >PRI? > >Well, it's not robbed-bit signaling, from what I understand, which I guess >means it is "out-of-band"? The signaling has its own channel. But the >signaling channel is bundled with the other channels in the circuit that >your order from the telco. > >BRI has the 2 Bearer channels and the one D channel that enter the CPE >together on a 2-wire circuit. > >With PRI, in Europe, ISDN enters the CPE on an E1 (4-wire ?) circuit. The >15th timeslot is used for signaling. > >With PRI, in the U.S., ISDN enters the CPE on a T1 4-wire circuit. The 24th >timeslot is used for signaling, if you can believe the books. > >What would be "the Cisco answer" to the question of ISDN signaling being >in-band versus out-of-band? > >Thanks, > >Priscilla > >Jens Neelsen wrote: >> >> Hi, >> >> Yes, it is one D channel per PRI. An E1 has 32 timeslots of >> 64kbps (=30B +1D +1timing). A T1 PRI has 24 timeslots + rest >> (=23D +1D). Timing is in the rest. >> >> You can save D channels if put more than one E1/T1 in a bundle. >> Then you need only one D channel per bundle. >> >> So the answer is: not more than one D channel per PRI. >> >> Jens >> >> --- maine dude wrote: >> > Hi All, >> > >> > Quick question I hope you can help me with. >> > >> > How many D channels does a PRI have? >> > >> > I always thought it was two, but its states 1 in most places. >> > >> > Text taken from the CCNP remote access guide (to make it more >> > confusing): >> > >> > there are 30 timeslots, leaving 2 timeslots for signalling and >> > framing. >> > Timeslot 0 is used for framing and timeslot 16 is used for >> > signalling >> > (counting 0-31). E1 PRI makes use of this same principle. >> > Timeslot 16 is the >> > D channel and timeslot 0 is used for framing information. >> > Please advise. >> > Regards,DJ >> > >> > >> > >> > --------------------------------- >> > With Yahoo! Mail you can get a bigger mailbox -- choose a size >> > that fits >> > your needs >> [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=65128&t=64999 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
