RE: What is the best way to become ISDN smart

From: Kenneth Wygand (KWygand@customonline.com)
Date: Sun May 02 2004 - 00:36:17 GMT-3


Kian,
 
A few things:
 
1) Yes, it is possible to bring up both channels through a single dial number. This is done through PPP Multilink and can only be done with PPP encapsulation (like you are using). You just need to add the command "PPP Multilink". Then you need to tell it _when_ you want the second channel to kick up. This can be load-based (ppp multilink load-threshold [1-255]), or automatic (ppp multilink links minimum 2). The reason this appears to work with the "real" circuit could be because the second link will come up _without_ multilink in the following scenario. Picture R1 calls R2 through the first dial number. If R2 doesn't realize it can reach R1 over this link, it may use the second dial number to call R1 back. You will see this if you "show isdn history". Check the direction (inbound or outbound) for each circuit connection (which router initiated the call).
 
2) The way you have this connection set up, R1 can never dial R2 for two reasons. The first reason is because there is no dial string associated with the dialer map. This is correct if you do not want R1 to ever dial R2. However, you also do not have any interesting traffic defined. Interesting traffic is used to reset the "idle-timeout" which, when expires, tears down the connection. There is an "idle-timeout" on each side of the circuit - in your case, there is an idle-timeout on both R1 and R2. When _either_ of these values on either side reaches 0, the circuit is torn down, period. R1 does not care what R2's idle-timeout value is - if R1's idle-timeout reaches 0, it will tear the circuit down. Since you have not explicitly defined the idle-timeout value, the default is 120 seconds. Anytime interesting traffic is seen crossing the link, this value is reset to the configured value (the default of 120 seconds in this case). However, you do not have any interesting!
  traffic defined through the configuration of a "dialer-group x" interface command and associated "dialer-list x" global command. You can either A) define interesting traffic across this link, B) set the idle-timeout value to a very high value like 9999 (I don't like this), or C) disable the idle-timeout value on router A through the command "no dialer idle-timeout". My preference is choice C if you want Router B to make all the dialing and teardown decisions.
 
3) You are using dialer watch. For whichever route you are watching, you must have an associated "dialer-map" mapping to that network. Even though this is not listed as a required task in the Dialer Watch configuration task list on the documentation CD, you will see it referenced in the notes within the configuration examples:
 
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fdial_c/fnsprt6/dcdbakdw.htm#19111
 
HTH,
Ken

        -----Original Message-----
        From: Kian Wah Lai [mailto:kian_wah@qala.com.sg]
        Sent: Sat 5/1/2004 10:48 PM
        To: Kenneth Wygand; 'MMoniz'; 'ccie2be'; 'CCIE Canidate'; ccielab@groupstudy.com
        Cc:
        Subject: RE: What is the best way to become ISDN smart
        
        

        R1 - ISDN - R2, only r2 can call r1
        This config works with a real ISDN line, but can't work on the ISDN
        simulator on PEC. Another thing with PEC ISDN is that I only get to bring up
        the 1st channel. For basic-net3 (both labs are using this), no SPID are
        required and my friend told me one number will bring up both channel.
        
        R1:
        interface BRI0/0
         ip address 172.16.12.1 255.255.255.0
         encapsulation ppp
         dialer map ip 172.16.12.2 name r2 broadcast
         isdn switch-type basic-net3
         no peer neighbor-route
         ppp authentication chap
        end
        
        R2:
        interface BRI0/0
         ip address 172.16.12.2 255.255.255.0
         encapsulation ppp
         dialer map ip 172.16.12.1 name r1 broadcast <num>
         dialer watch-group 1
         dialer-group 1
         isdn switch-type basic-net3
         no peer neighbor-route
         ppp authentication chap
        end
        
        Regards,
        Kian Wah Lai
        
        -----Original Message-----
        From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
        Kenneth Wygand
        Sent: Sunday, May 02, 2004 10:32 AM
        To: Kian Wah Lai; MMoniz; ccie2be; CCIE Canidate; ccielab@groupstudy.com
        Subject: RE: What is the best way to become ISDN smart
        
        Kian,
        
        Can you post your configurations and describe the problem you are having?
        Maybe we can help you! :)
        
        Ken
        
                -----Original Message-----
                From: nobody@groupstudy.com on behalf of Kian Wah Lai
                Sent: Sat 5/1/2004 9:11 PM
                To: 'MMoniz'; 'ccie2be'; 'CCIE Canidate'; ccielab@groupstudy.com
                Cc:
                Subject: RE: What is the best way to become ISDN smart
               
               
        
                One thing I'm curious about, I keep having problem with ISDN
        simulator :(
                However, when I copy the same config to a router with real ISDN
        line, it
                works perfectly fine.
               
                Regards,
                Kian Wah Lai
               
                -----Original Message-----
                From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
        Of
                MMoniz
                Sent: Sunday, May 02, 2004 3:53 AM
                To: ccie2be; CCIE Canidate; ccielab@groupstudy.com
                Subject: RE: What is the best way to become ISDN smart
               
                Well another alternative is to become a gold member or other level
        with
                IPExpert and you will have access to NUMEROUS escenarios that will
        not only
                give you explanations but also the configs if you so choose to look
        at. All
                of them are
                CCIE level but they also have CCNA and NP level.
               
                This is inlcuded if you take like the VCLass or any other class I
        believe
                and it makes picking labs to do very simple.
               
                For instance if I only want to go over ISDN they have a few labs
        that are
                just ISDN but also many other complex routing labs that include
        ISDN.
               
                Not that I am suggesting that any of the other products out there
        are not
                quality, but to me being able to access via
                a "virtual" means is important to me. I want to be able to access
        labs no
                matter my physical location.
               
                But it still all boils down to the same thing!!!learn, practice
        practice
                practice
               
                just my opinion,
               
                mike
               
               
               
               
               
                -----Original Message-----
                From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf
        Of
                ccie2be
                Sent: Saturday, May 01, 2004 3:21 PM
                To: CCIE Canidate; ccielab@groupstudy.com
                Subject: Re: What is the best way to become ISDN smart
               
               
                My suggestion would be to get your hands on a large set of practice
        labs and
                practice the isdn portion of each one. After doing 20 to 40 of
        these
                practice labs, you'll feel fairly confident of your ability to
        handle ccie
                level isdn config's. Of course, if there are other topics you want
        or need
                to practice, you'll find them covered in the practice labs as well.
               
                Lots of companies these days offer practice lab workbooks, but for
        my money,
                I think those from Internetwork Expert are the best. They include
        with
                their practice labs comprehensive explanations of their solution at
        no
                additional cost whereas IPExpert offers no explanation at all or
        just a
                superficial one at best.
               
                Each company I think also provides a sample lab you can download for
        free so
                you can decide based on your assessment of their sample lab.
               
                good luck
                ----- Original Message -----
                From: "CCIE Canidate" <cisco@heartofdarknessstudios.com>
                To: <ccielab@groupstudy.com>
                Sent: Saturday, May 01, 2004 12:05 PM
                Subject: What is the best way to become ISDN smart
               
               
> Hi everyone!
>
> I know that there is a way more gray matter here than at my house.
> Basically, I have all of the right gear and can understand the
        basics,
> AND have already read a ton of Cisco documents, Kaslow's book, the
        CISCO
> Press books, among others....and still am not sure how best to
        assemble
> the most efficient configs required for CCIE level work. I want
        to get
> the opinions of group members on what materials give me the "BEST"
> crawl, walk, run steps, procedures, and examples of how to setup
        ISDN in
> preparation for the lab.
>
> Thanks,
>
> ISDN challenged guy
>
>
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        _______________________________________________________________________
                Please help support GroupStudy by purchasing your study materials
        from:
                http://shop.groupstudy.com
               
                Subscription information may be found at:
                http://www.groupstudy.com/list/CCIELab.html
               
               
        _______________________________________________________________________
                Please help support GroupStudy by purchasing your study materials
        from:
                http://shop.groupstudy.com
               
                Subscription information may be found at:
                http://www.groupstudy.com/list/CCIELab.html
        
        _______________________________________________________________________
        Please help support GroupStudy by purchasing your study materials from:
        http://shop.groupstudy.com
        
        Subscription information may be found at:
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