From: Scott M Vermillion (scott_ccie_list@it-ag.com)
Date: Sat Dec 06 2008 - 16:58:28 ARST
Hi Nit,
This is one area you need to be careful with Dynamips! As you probably
know, you can get away with not issuing the 'clockrate' command on *either*
end of a serial link in Dynamips. But with physical routers, the clocking
of the actual bits of information needs to come from somewhere. In the real
world, this would likely be your carrier gear and there again you wouldn't
configure clockrate on any of your CPE stuff (and in this case both of your
routers would indeed be considered as "DTE"). But physical routers
back-to-back do require that one or the other generate a clock signal/act as
DCE to, well, clock the bits in and out. So it's best to stay in that habit
so that when you hit a mock lab or a real lab, you don't overlook this
little detail and waste precious time troubleshooting a self-inflicted
problem!
Note that this is totally independent of any serial encapsulation scheme: it
would apply to FR, HDLC, PPP, and so forth. Lastly, another thing that
Dynamips types need to keep in mind is cabling in physical router
back-to-back scenarios. It will be the actual cable that will dictate which
end is DCE and which end is DTE. This will in turn dictate which end you
need to configure the clockrate on. That can be discovered via the 'sh
controllers' command for the serial interfaces on either end of the link.
Of course, in the real world, it can also be discovered by looking at what's
stamped onto the connector body! ;~) But you won't have that luxury in most
lab scenarios...
Regards,
Scott
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Nitro Drops
Sent: Saturday, December 06, 2008 4:29 AM
To: ccielab@groupstudy.com
Subject: Encap PPP
When configuring PPP authentication, we have to encap ppp.
In IE solutions, one end of the router always has 'clockrate 64000'
configured.
Shouldnt 'clockrate' be configured on both routers since both routers are
considered DTE?
This archive was generated by hypermail 2.1.4 : Thu Jan 01 2009 - 12:53:07 ARST