to further belabor this point, let me ask - can you have a rip network when
all directly connected interfaces of all routers are /29? or /24 subnets of
the 114.0.0.0 network?
Can a RIP router that has all directly connected interfaces with /16 subnets
receive and place into it's routing table routes with a /22 masks?
the answer to both is yes indeed!
in the second case, this is a trick question. has to do with the Cisco
defaults for RIP receive.
classful/classless behaviour has nothing to do with what is in the routing
table. ( well, see below ) classful/classless behaviour has nothing to do
with subnetting, or network numbers or broadcast addresses of networks.
classful/classless behaviour has everything to do with how a routing
protocol behaves in situations where there are variably subnetted interfaces
( how to advertise routes and what route to advertise ) and with how the
routing process behaves when the destination network does not match a
routing table entry. e.g. all my interfaces are /27 and my destination
address falls into a /27 subnet which is not assigned to an interface.
the question is a trick question designed to mislead people into thinking
that classfulness has something to do with subnetting.
Chuck
P.S. Leigh Anne, I have the files now. heh heh heh.
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of
Leigh Anne Chisholm
Sent: Tuesday, July 24, 2001 5:11 PM
To: [EMAIL PROTECTED]
Subject: RE: ccna challenge question [7:13565]
Classful addressing doesn't mean that routers do not look at the subnet
mask. Au contraire! Routers ALWAYS are concerned with subnet mask
information!
Classful addressing just means that a router that receives a routing update
for a network for which it does not have a directly connected interface will
assume the standard classful subnet mask. In the case of a router that does
have a directly connected interface that is using a subnet mask that is
borrowing bits from the host portion of the mask, it applies that mask to
the advertised network information. Variable subnet masking (subnet masks
of different lengths - /25, /26, /27 used in conjunction with the same
network) is not supported.
-- Leigh Anne
At 05:48 PM 7/24/01, Guy Russell wrote:
>Actually I disagree...
>
>Routers using Classful addresses, do not look at the subnet mask, nor do
>they transmit the subnet mask...Since the term classful was used, we would
>obviously be talking about the routing protocol, so a broadcast would be
>based only on the first octet to decide.
>
>Now a machine is not dependent on classful, it understands its own subnet
>mask, and then the answer would be that... But the term Classful negates
>that theory of it being a computer or other host...
>
>
>
>----- Original Message -----
>From: Priscilla Oppenheimer
>To:
>Sent: Tuesday, July 24, 2001 5:28 PM
>Subject: Re: ccna challenge question [7:13565]
>
>
> > At 04:28 PM 7/24/01, Ed Moss wrote:
> > >The key in the question is the word "classful".
> >
> > Classful doesn't mean it has to end on an 8-bit boundary.
> >
> > >This is a Class B address
> > >with a 16 bit classful mask.
> >
> > It's not 16-bit. It says the mask is 255.255.254.0. That's 23 bits in
the
> > prefix (network) part.
> >
> > The answer is B. Put it in binary to understand it.....
> >
> > Priscilla
> >
> > >I would have to say the correct answer would
> > >be 'C' 172.18.255.255.
> > >Ed
> > >
> > > > Using classful assumptions, what is the directed broadcast address
for
> > > > 172.18.2.0 with the mask 255.255.254.0?
> > > > a) 172.18.2.255
> > > > b) 172.18.3.255
> > > > c) 172.18.255.255
> > > > d) 172.18.0.0
> > >
> > > > Answer
> > > > b)
> > ________________________
> >
> > Priscilla Oppenheimer
> > http://www.priscilla.com
________________________
Priscilla Oppenheimer
http://www.priscilla.com
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7&i=13697&t=13565
--------------------------------------------------
FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
