The Van Jacobson compression could be a problem, but I doubt it. You would
see a problem during the first connection. It is more likely a problem with
ppp multichassis multlink. There are some older ISP ISDN boxes out there
that are not able to do multichassis multilink(I can't remember what they
are called at the moment).
The following scenario takes place:
You initially connect to your first b channel and successfully negotiate ppp
multilink at layer 2 but don't have enough traffic to bring up the second b
channel. Sometime later, your second channel comes up and you connect to a
different ISP device and negotiate ppp again. the ISP's second box is
unaware of the first connection and installs a new route. You are now
sending data out on both channels but only receiving on the second because
that is the only connection they currently have a route back to you. After a
time, the second channel drops based not enough bandwidth used on the first
channel and the fast timer. The ISP no longer has a route to you.
You can check this a couple of ways. First, by running debug ppp neg and
watch you getting a new route installed with IPCP, and second, with a debug
ip packet detail and watch the packet leave the first b channel after the
second channel drops but never receiving any incoming packets. Both debugs
are processes CPU intensive and may crash the router so be careful.
They will usually recommend to less knowledgeable customers to set the
load-threshold higher and the problem goes away. But of course, this is
because the second channel doesn't come up.
HTH
MikeN
Network Engineer
""Andy Barkl"" wrote in message
[EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> I have an ISP who claims the local Telco claims that my intermittent ISDN
> BRI connections are based on the lack of VJ compression.
> I have enabled VJ compression, however the Telco claims it is still not
> visible in their log files for my line.
>
> I never did have this with my previous ISP in our 3 year agreement.
>
>
> The problem appears repeatable, when I reset my router, everything runs
> fine for about 4 hours. I beleive that during "auto-reconnect", the ISP's
> router is prohibiting routing. The problem is fixed with a cold restart.
>
> Both of the BRI channels appear to be ready but I am unable to ping
> anything outside of my network.
>
> I have replaced the router, ran debug commands until my eyes bugged-out,
> but I cannot find any problems with my side.
>
> Does anyone have any ideas?
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