Tech Support > Computer Hardware > Routers > Re: Cisco 1003 how to dial in to one isp with multiple dial strings?
Re: Cisco 1003 how to dial in to one isp with multiple dial strings?
Posted by Aaron Leonard on January 20th, 2004


On Mon, 19 Jan 2004 23:02:46 +0100, Matthias Fischer <dr.mf@ngi.de> wrote:

~ OK everyone, please be patient - I'm not so experienced in programming
~ Ciscos, but trying to learn (I hope my english is enough for this...).
~
~ The hardware:
~ Cisco 1003 ISDN Router, Ethernet0, Bri0 etc., IOS 12.1(16), 16MB RAM/4MB
~ Flash, working fine...
~
~ Configured with ConfigMaker 2.6 (ok, ok, just for beginners, but I got
~ this thing working...!)
~
~ Meant to dial an ISP number (NGI, for example 123456)
~ so me and the rest of my family can use internet (DSL is too expensive
~ around here).
~
~ So I built a small homenetwork with "Ethernet O" using "EthernetLAN"
~ plus "Dialer 1 BRI 0" using "Easy IP"/NAT on "ISDN" (NGI).
~ No DHCP, every workstation has a static IP-address.
~
~ I failed building working access-lists with ConfigMaker (Hm!) so I wrote
~ some by my own for delivering through a TFTP-Server (3COM), which is ok
~ for now. They are still not perfect, but fit my needs (Any tips...?).
~ So, everything was fine, but...:
~
~ NGI has only *one* telephone-number for me to dial (123456) so the
~ "Cisco1003 places call to 'NGI' at phone number(s)"-field has just this
~ single telephone-number in it.
~
~ But:
~ On weekends I can surf for free (ISDN-XXL), if I dial another *couple of
~ numbers* (about 16). They give you this telephone-numbers, so you an try
~ which one will be free for you to use.
~ So I built another configuration especially for weekends, to be
~ delivered through ConfigMaker.
~
~ The problem:
~ The corresponding entry field in ConfigMaker just says "If there are
~ multiple phone numbers, separate the phone numbers with a comma." I did
~ this, and it worked. Fine. Hm! Really?
~
~ Then I started looking at the dialer configuration - CFMaker placed all
~ this numbers with "dialer string"-entries, one under another, in the
~ section "interface dialer 1".
~
~ Questions 1:
~ Wouldn't it be better to use something like the "dialer map" command?
~ Cisco Reference says:
~ "To configure a serial interface or ISDN interface to place a call to
~ multiple [!] sites and to authenticate calls from [I just want to dial
~ *out*!] multiple sites, use the second form of the dialer map command:
~ dialer map protocol next-hop-address [name hostname] [spc] [speed 56 |
~ speed 64] [broadcast] [dial-string[:isdn-subaddress]]"
~ I tried this in "configuration mode" for "interface 1", but what do I
~ need for "next-hop-address"? What config script shuold I write?

If you have multiple numbers by which you wish to dial ONE site,
then I would use multiple dialer strings, not dialer maps.

Actually, if you have multiple sites to dial, I would use multiple
separate dialer profiles, not dialer maps.


~ Questions 2:
~ 1. Is ConfigMaker right in placing all dialing-numbers like this?
~ It looks like:
~ "interface Dialer 1
~ description connected to NGI-XXL
~ ip address negotiated
~ ip nat outside
~ no ip split-horizon
~ encapsulation ppp
~ dialer in-band
~ dialer idle-timeout 120
~ dialer string 02143100000
~ dialer string 02018563737
~ dialer string 02018471581
~ dialer string 02336860870
~ dialer string 02330989111
~ dialer string 02501269111
~ ...and so on..."

Yes, that looks fine to me.

~ 2. Is there a better solution for this?

What don't you like about this?

Aaron

---

~ Any help appreciated - the Cisco manuals are mostly here - but $Brain is
~ still V1.00 and no chance of upgrading... :-))
~
~ Regards
~
~ Matthias

Posted by Aaron Leonard on January 21st, 2004


~ > ...
~ >~ "interface Dialer 1
~ >~ description connected to NGI-XXL
~ >~ ip address negotiated
~ >~ ip nat outside
~ >~ no ip split-horizon
~ >~ encapsulation ppp
~ >~ dialer in-band
~ >~ dialer idle-timeout 120
~ >~ dialer string 02143100000
~ >~ dialer string 02018563737
~ >~ dialer string 02018471581
~ >~ dialer string 02336860870
~ >~ dialer string 02330989111
~ >~ dialer string 02501269111
~ >~ ...and so on..."
~ >
~ >Yes, that looks fine to me.
~
~ Hm, I just thought that this was to easy...perhaps I an relax a bit...
~
~ >~ 2. Is there a better solution for this?
~
~ >What don't you like about this?
~
~ Because I found this in the "IOS 12.1 Command Reference" manuals...
~
~ "Dialer string - To specify the string (telephone number) to be called
~ for interfaces calling a single [!] site, use the dialer
~ string command in interface configuration mode..."
~
~ Ok, I'm calling a *single* side (Hm, when I think about it - is this
~ *really* a single side?). I interpreted this command description in the
~ way that there should be only *one* "dialer string"-entry for an
~ "interface dialer".

No, you can have multiple dialer strings on an interface
(legacy dialer or dialer profile.) As far as whether a given
destination is a "single site" - this means (from our perspective)
that the authentication/routing information is the same for all calls.

[ skipping to what you want ]

~ Perhaps I'm making this "dial-problem" a bit too complicated than it
~ actually is.
~ But:
~ What I *want* is that the "dialer interface" dials one of the given
~ numbers - using multiple b-channels with a "load-threshold" of 70-90.
~ This is working using the above "dialer string"-entries - connection
~ established, everything ok, single-channel.
~ But when the load gets to high the interface dials the *next*
~ "dialer-string"-entry (not the same) typically blocking the interface
~ (so it seems to me) - nothing comes in, nothing comes out...

If you bring up multiple calls via different dialer strings, and
things stop working, then I must assume that you are NOT really
dialing a "single site". For example, if you are doing multilink
PPP (MLPPP), then perhaps the different numbers are hitting different
routers, but those routers do not support multichassis multilink PPP (MMP).

To have better control over this behavior, ideally you would
want to use the "rotating through dial strings" feature,
http://www.cisco.com/univercd/cc/td/...8/ftrotdls.htm .
However this appeared in 12.2(8)T which is not available for
the 1003.

~ Final question:
~ How would I have to configure/expand my current "interface dialer 1"
~ using "dialer profiles"? I didn't find any useful examples yet...

For dialer profiles, the basic idea is like this:

interface BRI0
dialer pool-member 1

interface dialer1
encapsulation ppp
dialer pool 1
dialer remote-name ROUTER1
dialer string 5551234
interface dialer2
encapsulation ppp
dialer pool 1
dialer remote-name ROUTER2
dialer string 5554321

etc.

You can theoretically bring up multiple
dialer profiles simultaneously (one on one
B channel, another on the other.) This might
resolve an issue where you are trying to do
an MLPPP bundle where there are multiple remotes
with that are not doing MMP.

As I recall it, you had some numbers that
you wanted to dial at certain times of day,
and other at other times, right? In that case,
it might make sense to use dialer lists that
use time-based ACLs. See
http://www.cisco.com/univercd/cc/td/...1/timerang.htm

Have fun,

Aaron