PPP callback (yes, again)

From: Keith Kruepke (Keith@xxxxxxxxxxx)
Date: Sun Jul 16 2000 - 23:45:25 GMT-3


   
Well, my efforts with PPP callback have not been any more successful the second
 time around. I have modified my configs so that they look almost identical to
 those in the documentation. Still I am having this one problem.

Let me start by saying that PPP is working in most senses of the word--it's jus
t not working the way I want it to or would expect. So I don't plan on spendin
g much more time on this. But I thought I would put up one last request to the
 group, just in case something will jump out at someone about this config. Som
e of the stuff in here is probably not necessary, but I have been adding stuff
to see if it helps. My configs are at the bottom of this message.

With these configs, I try to ping from R5 to R3. R5 dials, authenticates, and
disconnects, as it should. However, it does this five times before giving up.
 Usually, this repeated dialing prevents R3 from finding an available interface
 to dial out on. If I do an extended ping and select to send only one packet,
then it works fine.

Note that if I remove the 'dialer enable-timeout' command from R3, R3 waits to
dial until all five of R5's dial attempts. In this case, it works, but by then
 all five pings have timed out. If I were to send an even bigger flood of traf
fic (such as would happen in the real world), then the problem would probably s
till happen, as R5 would dial many more times over. The sample configs show an
 enable timeout of 2, which makes sense, because you want the server to dial ba
ck right away, rather than making the traffic wait.

So as I see it, this is a problem with R5, not R3. R5 should wait after reques
ting a callback, not dial again immediately. (I would have thought that to be
the default behavior of callback...) But I've tried all sorts of things (inclu
ding 'dialer enable-timeout', 'isdn fast-rollover-delay', 'dialer hold-queue'),
 none of which have done the trick.

If anyone can help me out, that would be great. If anyone has a working PPP c
allback config, feel free to send that if it is easier.

Thanks all,
Keith

-----
R5 (callback client) v12.1(2):

interface BRI0/0
 ip address 130.130.101.21 255.255.255.252
 encapsulation ppp
 dialer enable-timeout 30
 dialer map ip 130.130.101.22 name R3 broadcast XXXXXXX
 dialer hold-queue 100 timeout 60
 dialer-group 1
 isdn switch-type basic-ni
 isdn spid1 XXXXXXXXXX0101
 isdn spid2 XXXXXXXXXX0101
 isdn fast-rollover-delay 45
 ppp callback request
 ppp authentication pap callin
 ppp pap sent-username R5 password 7 1306181C055957
-----
R3 (callback server) v11.3(3a)T1:

interface BRI0/0
 ip address 130.130.101.22 255.255.255.252
 encapsulation ppp
 dialer callback-secure
 dialer idle-timeout 60
 dialer enable-timeout 2
 dialer map ip 130.130.101.21 name R5 class cllbck broadcast XXXXXXX
 dialer hold-queue 50 timeout 60
 dialer-group 1
 isdn switch-type basic-ni
 isdn spid1 XXXXXXXXXX0101
 isdn spid2 XXXXXXXXXX0101
 ppp callback accept
 ppp authentication pap callin
 ppp pap sent-username R3 password 7 02050B5505555A
 hold-queue 75 in
!
map-class dialer cllbck
 dialer callback-server username
-----



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