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=65110&t=64999 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
