richard dumoulin wrote: > > Priscilla, > > Do you remember the discussion about IP unnumbered ? Sure you > do. You wrote "Now, network management is a concern, however. > If your serial interface is unnumbered, you can't ping it or > send it SNMP messages. With those functions, the serial port > acts as an end host and must have a network-layer address. > That's the tradeoff". > > I have found in Cisco ISP essentials book, the following: "Many > ISPs use monitoring systems that use ping to check the status > of the leased line. Even if the customer unplugs the LAN, an > alarm will not be raised on the ISPs management system. This is > because the customer router still knows that the LAN IP > address is configured on the system and is "useable" ". (page 46)
Good grief. You all had an entire discussion with my name on it while I was out of town! ;-) My first reaction was that the two statements are not in disagreement as someone else said. Richard, you didn't quote enough of the book. The statement that you quoted doesn't say that the serial interfaces are using unnumbered. I guess you assumed we knew that. My second reaction after seeing the results of your testing, Richard, was "interesting!" I definitely wouldn't have expected the ping to work when the Ethernet interface was down, but it did. I tried it in my lab too and was able to reproduce the results. I think I come to the same conclusion that you did, which is that you can ping an unnumbered serial interface. It's kind of stretching the truth though. You're pinging the router, but are you really pinging the serial interface when you're using an address that is not associated with the serial interface? But I admit, I'm acting like Bill Clinton now and questioning the meaning of words. ;-) I like Chuck's explanation about the Router ID. Thanks for filling us in on this, Richard. My routers are ancient. They are running 11.0(5) and they worked like yours. So it seems like it's worked this way for a long time and nobody knew!? ;-) Trace route works too, by the way, even when the Ethernet interface is down. I don't have an easy way to test SNMP. It might work too. Priscilla > > Regards. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=49605&t=49347 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
