From: Stan Buskus (stan.buskus@xxxxxxx)
Date: Thu Oct 05 2000 - 07:37:56 GMT-3
If you do not include ther fragement statement, will the fragment size default
to
the MTU?
> Jason,
>
> I believe we use method two. You would use the following command
>
> interface virtual-template1
> bandwidth 78
> ip address 131.180.60.5 255.255.255.0
> ip mroute-cache
> ppp multilink
> ppp multilink fragment-delay 8
> ppp multilink interleave
>
> Fragment size is calculated using the following method.
>
> fragment size = bandwidth X fragment-delay /8
>
> So based on my example above, the fragment size would
> be set to 78 bytes.
>
> Hope this helps
>
> Ken
>
> "Jason T. Rohm" wrote:
> >
> > Does anyone know where I can find documention on Cisco's implementation of
> > RFC 1990 (MLPPP)? In particular I am interested in the way Cisco has
> > implemented the fragmentation and dispatch mechanisms.
> >
> > I have a 1601 w/BRI WIC here. I am trying to determine if adding an analog
> > dial-up to the MLPPP bundle will increase performance. The reason I am
> > questioning this is because all of Cisco's documentation says that the
> > fragements are dispatched in a round-robin fashion.
> >
> > This would mean that the actual bandwidth available might be (Nx) where x
> > is the lowest bandwidth the channels (3 x 33.6 = 100.8 kbps). (See RFC
> > comments below.)
> >
> > The RFC outlines two methods of breaking up the packet. First, break up th
e
> > packet into unequal fragments using the bandwidth of the channel to
> > determine size. Second, break up the packet into numerous small fragments
> > and dispatch the fragments proportionately to the bandwidth.
> >
> > If Cisco uses method one, then a round-robin dispatch would make sense.
> > However, if this is true, how does the IOS determine the bandwidth of the
> > analog line? (Since the external modem does not return a connect speed).
> >
> > Thanks
> >
> > -Jason
> >
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