ip subnet-zero allows the subnet with a zero bit to be
used. For example, 10.0.0.0/24 would normally be
disallowed per RFC, but subnet-zero allows its usage.
ip classless allows the router to operate with summary
addresses within the major network boundary. For
example, consider a router with 10.1.1.0/24 and
10.0.0.0/8 in its table. A packet destined for
10.2.1.0/24 would be dropped without classless, as
there is no specific match within the major network
boundary to forward to. All routes (classful) must be
within the 'interface' intrepretation. ip classless
will forward the packet towards the shorter prefix
match presuming that the destination is known behind a
summarization point.
--- George <[EMAIL PROTECTED]> wrote:
> What is the difference between Classless and
> Classful ?
>
> "McCallum, Robert"
> <[EMAIL PROTECTED]> wrote in
> message
>
news:[EMAIL PROTECTED]
> .uk...
> >
> > ip subnet zero is required when you want to use
> subnet zero i.e.
> 192.168.0.1
> > with a subnet mask of 255.255.255.0 is the zero
> subnet and can only be
> used
> > when you have ip subnet zero command. ip
> classless is another for
> routing,
> > with this if a packet comes in for a destination
> which is not exactly
> known
> > then it is dropped without the command ip
> classless on. With it on the
> same
> > packet will go to the "nearest matching route".
> >
> > -----Original Message-----
> > From: Bill [mailto:[EMAIL PROTECTED]]
> > Sent: 18 March 2001 05:22
> > To: Cisco Group Study
> > Subject: classless behaviour
> >
> >
> > Hi,
> >
> > To configure classless behaviour, we use "ip
> subnet-zero" and "ip
> > classless".
> > I never understand them, even after reading
> Doyle's bible.
> >
> > * When do we need them ?
> > * If we don't use them, what will happen ?
> > * Is there good example to show their effect ?
> >
> > Thank you in advance.
> >
> > Bill
> >
> > _________________________________
> > FAQ, list archives, and subscription info:
> > http://www.groupstudy.com/list/cisco.html
> > Report misconduct and Nondisclosure violations to
> [EMAIL PROTECTED]
> >
> > _________________________________
> > FAQ, list archives, and subscription info:
> http://www.groupstudy.com/list/cisco.html
> > Report misconduct and Nondisclosure violations to
> [EMAIL PROTECTED]
> >
>
>
> _________________________________
> FAQ, list archives, and subscription info:
> http://www.groupstudy.com/list/cisco.html
> Report misconduct and Nondisclosure violations to
[EMAIL PROTECTED]
=====
Robert Padjen
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