has anyone tried to use IRDP

[Singar]

Hi,

Has anyone tried to use IRDP to detect the router. If anybody used it, how long it takes to find the new gateway when the default gw is dead.

Thanks
singar

[U.SivaKumar_2]

hi,
I have setup irdp in a cisco router with rdpd clients in hp-ux . The setup works ok but not so efficient because of slow convergence.


In a multi-router environment enabling
irdp will cause routing table conflict and
routing loops.

regards,
U.SivaKumar

[Singar]

Hi US,

According to the IRDP RFC, router is suppoosed send Router Advertisement messages with the preference levels. I didn't quite understand why it has to give router conflict problem in the host.

singar

[U.SivaKumar_2]

Hi,
In multi-router environment irdpd is known to give practical problems.

regards,
U.SivaKumar

[Singar]

Hi Us,

My original concern in my question was, how long generaly a host takes to detect the dead gateway if IRDP is used, in multi-router configuration.

If you say that routing table conflicts happen in multi-router env, does it mean that host (hp box) doesn't use advertised router information for selecting the next gateway at all in the event of default gw failure?

[U.SivaKumar_2]

Hi,
I think i should not have used the word 'conflict'.

What actually I mean is slow convergence in detecting dead gateway will cause inconsistent
routing . By default advertising frequency is for 7 to 10 minutes and the lifetime of the irdp route is 30 minutes.

In hp-ux rdpd i think there is no option to reduce irdp route lifetime.

To reinforce my argument , i quote manpage
for rpdpd

"rdpd only becomes aware of link state changes when either a new
Router Advertisement message is received or a timer pops to age a
currently active default router added by rdpd. This may cause a
delay between an interface state change (e.g., ifconfig down) and
any necessary change to the kernel routing table."

regards,
U.SivaKumar