From: Chris Lewis (chrlewiscsco@gmail.com)
Date: Wed May 31 2006 - 10:16:40 ART
Petr is correct in that there is no way to "conditionally" fragment packets
in the IOS seen in the R&S lab. The 7500 has the capability to do this, but
of course you will not see that in the exam.
It is possible to configure a router to not fragment voice packets if you
make one big assumption, and that is you have voice ports directly connected
on the router and are doing voice over frame relay directly (not voice over
IP) and configure FRF.11 annex C. This is done with the vofr keyword in the
map-class and sets a field in the vofr header that effectively says "do not
fragment".
This would however be a big assumption as there are no longer voice ports on
routers in the R&S exam :)
Chris
On 5/31/06, Petr Lapukhov <petrsoft@gmail.com> wrote:
>
> AFAIK no. Fragmentation decision is based solely on packet size.
> Nothing else will affect it :) So the good away to keep you data
> unfragmented, is to compress them.
>
> The other possible way may be to change IP MTU at interface to some very
> low
>
> value, so that packets are "fragmented" at L3 :)
>
> HTH
> Petr
>
> 2006/5/31, Koen Zeilstra <koen@koenzeilstra.com>:
> >
> > So that's more an avoid scenario than a conditional fragmentation
> > scenario, I guess?
> >
> > Conditional fragmentation is not possible?
> >
> > -----------------------
> > One good reason why computers can do more work than people is that they
> > never have to stop and answer the phone.
> >
> > On Wed, 31 May 2006, Petr Lapukhov wrote:
> >
> > | Koen,
> > |
> > | You can try "frame-relay ip rtp header compression"
> > |
> > | That will shrink voice packets from average 60, to 20+, and
> > | will help them avoid fragmentation.
> > |
> > | HTH
> > | Petr
> > |
> > | 2006/5/31, Koen Zeilstra <koen@koenzeilstra.com>:
> > | >
> > | > Hi group,
> > | >
> > | > Suppose I want to use frame-relay fragmentation and use fragments of
> > 60.
> > | > However voice traffic should not be fragemented at all. How is this
> > | > achieved?
> > | >
> > | > A service policy under a FR can select more options however
> > fragmentation
> > | > is not part of the policy-map options.
> > | >
> > | > On DocCD I found frame-relay ip rtp priority. Hoever in my opionion
> > this
> > | > is a queueing strategy and not excluding traffic from being
> > fragemented.
> > | >
> > | > thanks in advance for your answer,
> > | >
> > | > Koen
> > | >
> > | >
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