From: Jay Hennigan (jay@xxxxxxxx)
Date: Fri May 18 2001 - 21:13:29 GMT-3
On Fri, 18 May 2001, Jeongwoo Park wrote:
> Shouldn't router's source clocking be configured depending on csu/dsu's
> source clocking?
No!
> For example, csu/dsu's source clocking was configured as internal. Then what
> type of clocking source should the router that is directly connected with
> this csu/dsu have?
The circuit will have a single clock source that drives everything. This
will either pe provided by telco, in which case both CSUs are set to "Line",
or by ONE of the CSUs which will be set to "Internal". The router is DTE
and will receive clock from the CSU.
> Should this router have line or internal or something else?
The only time this would be a question would be if the router has a built-in
CSU such as a WIC (service-module) or T-1 controller. If your CSU is an
external box connected by a v.35 cable, then the router should not be set
to provide clock at all, and in fact such should not be a configurable
option if you are using the right cable.
> Or am I totally missing something?
One clock per circuit. Either provided by telco and both of your CSUs
are set to line, or by ONE of your CSUs by setting ONE CSU to Internal.
The router "clock rate" should not be an option if you're using the
correct DTE cable.
> oh, one more thing that pops out of my head..
> I have seen a router 1740 that has csu/dsu module within the router. Then
> what is the deal in this case?
The settings of the CSU are configured in interface configuration mode
by the service-module T1 commands in interface configuration mode, thusly:
router(config-if)#service-module t1 ?
clock Service module clock source
data-coding Service module DCE line coding
fdl Specify the FDL standard for a DS1 data link
framing Framing format
lbo Line Build Out format
linecode Line coding format
remote-alarm-enable Remote/Yellow alarm enable
remote-loopback Remote Loopback/RL disable
timeslots Fraction timeslots
Default is timeslots 1-24, clock source line, linecode B8ZS, framing ESF
which is usually right for a T-1 data circuit.
Verify the above with telco and the other end of the circuit.
-- Jay Hennigan - Network Administration - jay@west.net NetLojix Communications, Inc. NASDAQ: NETX - http://www.netlojix.com/ WestNet: Connecting you to the planet. 805 884-6323 **Please read:http://www.groupstudy.com/list/posting.html
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