From: Raphael Gallegos (raphaeljg@xxxxxxxxxxx)
Date: Sun Feb 03 2002 - 06:52:22 GMT-3
IGRP does not understand 0.0.0.0, however eigrp does understand 0.0.0.0, and
yes it is ok for eigrp to redistribute a default route and mark it as an
external route with 170 admin distance. eigrp is a classless protocol, so it
will advertise a route with its correct subnet mask to its neighbor, which
is good, but if you want to summarize to a classfull range on a particular
ip subnet, then go ahead and use the ip eigrp "as" summary address command
under the interface, and you can even summarize the 0.0.0.0 address.
s0
ip summary-address eigrp 10 0.0.0.0 0.0.0.0
typically you would use default network command with eigrp only if you want
multiple candidate default routes marked with an *.
Rip does understand 0.0.0.0
Raphael
>From: michael robertson <michael_w_2ca@yahoo.ca>
>Reply-To: michael robertson <michael_w_2ca@yahoo.ca>
>To: Rodney Thomson <rodneyt101@hotmail.com>
>CC: ccielab@groupstudy.com
>Subject: RE:EIGRP default network
>Date: Sun, 3 Feb 2002 01:01:56 -0500 (EST)
>
>Hi, Rodney,
>
>I have read the link before. THank you for your link
>anyway. But the problem for me is the question I
>asked. I don't find the information for the question I
>asked.
>
>As the paper says that EIGRP and IGRP does't
>understand 0.0.0.o, But If I use redistribute 0.0.0.0,
>EIGRP process will consider 0.0.0.0 as an external
>route ( in this case, will this be considered default
>route). and also the white paper doesn't answer
>exactly the other two questions.
>
>Thank you for your help.
>
>michael
>
>--- Rodney Thomson <rodneyt101@hotmail.com> wrote:
> > Hi Michael,
> >
> > Here is a very good whitepaper on what you are
> > looking at, if you haven't
> > seen it already.
> >
> > http://www.cisco.com/warp/public/105/default.html
> >
> > I hope this helps.
> >
> > Regards
> >
> > Rodney
> >
> > >Hi, Group,
> > >
> > >I have a question about default network about
> > eigrp.
> > >
> > >Question 1:
> > >
> > >As Eigrp doesn't understand 0.0.0.0 default
> > network,
> > >so you have to explicitly specify a default
> > network
> > >with command ip default-network, In my case, The
> > >topolody is as follows:
> >
> > R1-----R2-----R3---
> >
> >
> > routing protocol is eigrp
> > If I configure a loopback address in R3 with address
> > 172.16.1.1 and say ip default-network 172.16.0.0 (
> > should be classful for default network). When no
> > auto-summary is on, I can't see default network in
> > R2,
> > what I see is a network 172.16.1.0 as follows:
> >
> > ---------------------------------
> > 172.16.0.0/24 is subnetted, 1 subnets
> > D 172.16.1.0 [90/1764352] via 192.168.1.246,
> > 00:15:00, Serial0/1
> >
> > ----------------------------------
> >
> >
> > My question here is that do you have to enable
> > auto-summary in order to propogate a default network
> > because it's classful.
> >
> > I can see in R3 it's marked as default gateway as
> > follows:
> >
> > ----------------------------------
> > * 172.16.0.0/24 is subnetted, 1 subnets
> > C 172.16.1.0 is directly connected,
> > FastEthernet1/1
> >
> > ----------------------------------
> >
> > Question 2:
> > IF i don't use ip default network, I use 0.0.0.0
> > instead in R3 and then redistribute this static
> > route
> > to EiGRP network, I have seen also in R2, 0.0.0.0 is
> > marked as a default network, Can i do this way as a
> > default network? I am not sure it's a standard way
> > or
> > not. But EIGRP doesn't understand 0.0.0.0, I
> > redistribute here, I think it's OK, any comment?
> >
> > Question 3:
> >
> > If my routing protocol is RIP in the above scenario,
> > I
> > found that RIP doesn't understand 0.0.0.0 also, You
> > have to redistribute. Is this againt Jeff's book
> > page
> > 751 's static default route case study.
> >
> > I have seen somewhere that you need to explicitly to
> > redistribute 0.0.0.0 since a IOS version which I
> > forget.
> > Is it so??
> >
> >
> > Any help will be appreciate as always
> >
> >
> > Regards
> >
> > michael
> >
> >
> >
> >
This archive was generated by hypermail 2.1.4 : Thu Jun 20 2002 - 13:46:10 GMT-3