From: Arvind Yadav (arvindyadav@comcast.net)
Date: Mon Jan 26 2004 - 04:07:55 GMT-3
use "ppp multilink links minimum 2" If will make both the channels up
immedialty ....irrespective of load.
----- Original Message -----
From: "Phil" <ciscostudent1@yahoo.com.br>
To: "Nauman Khan" <mustafa@247emails.com>; <ccielab@groupstudy.com>
Sent: Sunday, January 25, 2004 10:53 AM
Subject: Re: ISDN Multilink ( Problem to bring 2nd channel up )
> I am using a Atlas550 as my ISDN simulator and my 2nd channel wasn't
coming up. I changed the configuration in the Atlas550 and it is coming up
now but it takes consistent 30 seconds to the 2nd channel to come up. I have
used the Teltone2000 in the past and both channels used to come up together
with the "dialer load-threshold 1 either". I changed the config to be as
basic as it can be and it always takes 30 seconds for the 2nd channel to
come up:
>
> ==============================
> R3:
> !
> hostname R3
> !
> username R5 password 0 cisco
> !
> isdn switch-type basic-ni
> !
> interface BRI0/0
> ip address 1.1.1.1 255.255.255.252
> encapsulation ppp
> no ip route-cache
> no ip mroute-cache
> dialer idle-timeout 30
> dialer map ip 1.1.1.2 name R5 broadcast 5552000
> dialer load-threshold 1 either
> dialer-group 1
> isdn switch-type basic-ni
> isdn spid1 21255510000101 5551000
> isdn spid2 21255510010101 5551001
> no peer neighbor-route
> no cdp enable
> ppp authentication chap
> ppp multilink
> !
> dialer-list 1 protocol ip permit
> !
> dial-peer cor custom
> ================================================
> R5:
> !
> hostname R5
> !
> username R3 password 0 cisco
> !
> isdn switch-type basic-ni
> !
> interface BRI0/0
> ip address 1.1.1.2 255.255.255.252
> encapsulation ppp
> no ip route-cache
> no ip mroute-cache
> dialer idle-timeout 30
> dialer map ip 1.1.1.1 name R3 broadcast 5551000
> dialer load-threshold 1 either
> dialer-group 1
> isdn switch-type basic-ni
> isdn spid1 21255520000101 5552000
> isdn spid2 21255520010101 5552001
> no peer neighbor-route
> no cdp enable
> ppp authentication chap
> ppp multilink
> !
> dialer-list 1 protocol ip permit
> !
> dial-peer cor custom
> !
> =================================
>
> Has anyone experienced this?
>
> Thanks,
>
> Phil
>
>
>
> Nauman Khan <mustafa@247emails.com> wrote:
> --- Nauman Mustafa wrote:
>
>
> phase90 wrote:
>
> >Nauman & Jay,
> >
> > Does this mean that if you were to look at the debug q921 or
> >q931 output of ISDN control plane you would see the other SPID # appear
in setup messages
> >even though it is not configured in the router?
> >
> Hi Jerry,
>
> IMHO, the router always starts trying to dial the numbers specified by
dial string under the bri interface...from top to bottom in order of
appearance.
>
> Consider these 2 scenarios:
>
> 1. You get 2 spids from telco and you have p2p connection b/w calling and
called router.
>
> Router A----------<>--------RouterB
>
> Lets say you want to bring the second B channel up once the load-threshold
crosses 20
> then you will have on router A
>
> int brix/y
> ip address .........
> dialer string xxxx
> dialar string yyyy
> dialer load-threshold 20
>
> --rest of the config--
>
> In this case, when router A gets interesting traffic, it bring up first B
channel
> Now, when the load threshold crosses 20, the router will dial the number
speciied in the first "dialer string"
> under the bri interface. So in this case , it will dial xxxx, it will get
a busy since the first B channel is up.
> Then it will dial the number in the dialer string command ,which is yyyy
and will bring the B channel up.
>
> Now, in the scenario, where you only get one spid, from Telco , it
normally means, that Telco has setup hunt group or
> automatic rollover on their side.Please refer to my previous post on this
topic on how automatic rollover works.
> So in this case you have one number or dial string that you configure on
your calling router to dial the remote router.
>
> So your above config will look like this:
>
>
> int brix/y
> ip address .........
> dialer string xxxx
>
> dialer load-threshold 20
> --rest of the config--
>
>
> In this secnario, when the load threshold crosses 20, the router will
still dial xxxx. It will get a busy but since
> the switch is configure for automatic rollover, it will hunt to the second
channel and will bring up the second B channel.
> So the two b channels can be brought up using only one single string and
is normally the case when Telco provide you with
> only one spid.
>
> As far as the ccie lab is concerned, I would just configure whatever is
given to us.
> If they only give one spid, then their isdn switch either should be
configured for rollover or they shouldnt be asking us
> to bring up the second channel up.
>
> ....just my 2 cents.
>
> Best Regards,
>
> -Nauman
>
>
> >
> >
> >Jerry
> >----- Original Message -----
> >From: "Nauman Khan"
> >To: "Jay Hennigan" ; "Nauman Khan"
> >Cc: "Yasser Aly" ;
> >Sent: Saturday, January 24, 2004 4:18 AM
> >Subject: Re: ISDN Multilink ( Problem to bring 2nd channel up )
> >
> >
> >
> >
> >>Jay Hennigan wrote:
> >>
> >>
> >>
> >>>I believe you are wrong, but this may be one of those "it depends" type
> >>>of things. SPIDs are layer 2 communication between the ISDN TE and the
> >>>switch, related to the actual raw B channel. If the switch requires a
> >>>spid for one channel, it will require it for the other as well. Note
> >>>that the real world may vary from a simulator and from the specific lab
> >>>environment.
> >>>
> >>>
> >>Hi Jay,
> >>
> >>Thanks for correcting me.
> >>I also think I am wrong when I say that:
> >>
> >>
> >>
> >>>You would need the second spid numbers if you want to bring the second
> >>>
> >>>
> >>channel up without considering load threshold. If you only specify one
> >>spid, then the second channel will only come up once your configured
>load
> >>
> >>
> >threshold is corssed. (Somebody can correct me if I am wrong)
> >
> >
> >>which then means, that the only way to bring the second channel up is
the
> >>
> >>
> >use of dialer load-threshold command ?
> >
> >
> >>but I was just trying to find out why we would ever need to specify
> >>2 spids, as Yasser asked. The only time I have seen 2 spid's needing to
be
> >>
> >>
> >specified (in real world) is when using a bas-ni switch type.
> >
> >
> >>Although it works with one spid too... (depending on how switch is setup
> >>from the telco side)
> >>
> >>Regarding your following comments:
> >>
> >>
> >>
> >>>SPIDs are layer 2 communication between the ISDN TE and the
> >>>switch, related to the actual raw B channel. If the switch requires a
> >>>spid for one channel, it will require it for the other as well. Note
> >>>that the real world may vary from a simulator and from the specific lab
> >>>environment.
> >>>
> >>>
> >>Its not necessary (in real world configuration) to have 2 spids to bring
> >>
> >>
> >up the second channel.
> >
> >
> >>For e.g. in DMS100 switch case, generally telco gives you only 1 spid
> >>
> >>
> >number. But that does not mean you have only one spid. You still dial out
on
> >2 channels.
> >
> >
> >>The way it works is there is a thing called automatic rollover or B
> >>
> >>
> >channel hunt group that Telco configures on their switch. No router
> >configuration involved.
> >
> >
> >>What it does is when we dial xxx string (which lets say is the only
string
> >>
> >>
> >that we got from Telco), it connects on first B channel. Now when router
has
> >to bring up 2nd channel, it again tries xxx string, and since telco has
both
> >b channels in one single hunt group or in automatic rollover,you will
> >connect on 2nd channel with the same xxx string.
> >
> >
> >>This is alternate to have multiple dial strings on the source router for
> >>
> >>
> >each B channel.
> >
> >
> >>Cheers,
> >>
> >>Nauman
> >>
> >>
> >>
> >>
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