From: Kenneth Sacca (ksacca@xxxxxxxxx)
Date: Mon Oct 02 2000 - 13:03:23 GMT-3
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 the
> 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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