From: Williams, Glenn (WILLIAMSG@xxxxxxxxxxxxx)
Date: Thu Mar 21 2002 - 10:53:35 GMT-3
Ok, appreciate this dialogue. So let me bounce this. Lets say I have two
routers on same vlan. (BTW, this is probably not what I would build but a
what if...) The ip 's of routers are 10.1.1.5 and 10.1.1.6. Both can get to
same places in the network, so kind of redundancy for that vlan. My
workstation says and has defined .6 is default gateway. But now .6 goes
down. Can .5 pretend to be .6 by using this irdp address command (you know
proxy advertise it) Would the PC have to be able to dynamically learn (that
is understand irdp) in this situation or no or does it matter?
Can Windows deal with IRDP to learn dynamically the default GW?
Glenn
-----Original Message-----
From: Tshon [mailto:tshon@netzero.net]
Sent: Thursday, March 21, 2002 7:31 AM
To: RSiddappa@NECBNS.com
Cc: erickbe@yahoo.com; Williams, Glenn; ccielab@groupstudy.com
Subject: Re: ip irdp address
Ok, I can understand that.
RSiddappa@NECBNS.com <mailto:RSiddappa@NECBNS.com> wrote:
But when we want to use IRDP in combination with HSRP. Will not not make a
differnce.
R.
-----Original Message-----
From: Tshon [ mailto:tshon@netzero.net <mailto:tshon@netzero.net> ]
Sent: Wednesday, March 20, 2002 11:12 PM
To: Erick B.
Cc: Williams, Glenn; ' ccielab@groupstudy.com
<mailto:ccielab@groupstudy.com> '
Subject: Re: ip irdp address
I go with Erick.
ICMP Router Discovery Protocol is for devices that can dynamically learn
their default gateway. The routers send out IRDP advertising themselves
as the default along with their preferences. The host chooses the higher
preference and starts using the router as it's gateway. The question comes
into play when you have two routers that could be the default gateway and
one of them doesn't support IRDP. The router that Does can proxy-advertise<
br>that router and the preference assigned that router. That way the host
can choose the appropriate gateway.
The Cisco IOS software can proxy-advertise other machines that use IRDP;
however, this is not recommended because it is possible to advertise
nonexistent
machines or machines that are down.
What the note says is that when the proxy-advertised router goes down,
the IRDP
router will continue to advertise the router anyway. Big problem, if it
has the higher
preference. I would use something like this in a three router or more
situation.
And let the proxy-advertised router get the least highest preference.
Erick B. wrote:
Hi,
I can't think of a practical example for this, but I
have played with this on some router configs I did in
my studies. By default, IRDP will announce the
interfaces IP address with default preference. With
this command you can have IRDP broadcast another IP
address besides the IP address on the router
interface.
Maybe this would be useful if you had a
router/fwall/etc that didn't support IRDP. You could
then announce that devices IP on the router via IRDP.
--- "Williams, Glenn" <mailto:WILLIAMSG@PANASONIC.COM>
<WILLIAMSG@PANASONIC.COM> wrote:
Does anyone know or can show how to practically use
the "ip irdp address"
command. The CCO says:
"The Cisco IOS software can proxy-advertise other
machines that use IRDP;
however, this is not recommended because it is
possible to advertise
nonexistent machines or machines that are down."
That is all I can find and it does not sink in to me
for how to use it.
TIA
GW
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