From: Mark Lasarko (mlasarko@co.ba.md.us)
Date: Thu Jan 13 2005 - 18:59:40 GMT-3
I agree Tim,
Restating once more for good measure...
(In the context of this example, of course)
I, R1 will send RP-reach announcements for my group 225.25.25.25
I, R1 will send these announcements at regular intervals....
(Every 60 seconds by default)
Furthermore,
I, R1 will (drop|expire) groups for which I receive no RP-reach
announcements, should I not receive an announcement for any
particular group within 3x the interval. (= 180 seconds by default)
In this example it's been 51 seconds since I, R1, last heard from R2
regarding
232.32.32.32, and I expect to hear back from R2 again in approximately
9 seconds. However, if I do not hear back I will continue to retain
this
association for 232.32.32.32 via R2 for an addition 120 seconds, by
default.
About the Auto-RP v. BSR, looks like the "RP-reachable" verbiage is
applicable to both.
http://www.cisco.com/univercd/cc/td/doc/product/software/ios123/123cgcr/iprmc_r/ip3_i2g.htm#wp1073699
As for the *interval* itself, 16383 seconds ~ 273 minutes ~ 4.55 hours
In theory a maxed-out interval could potentially leave a lame
connection up for ~ 13.65 hours.
Isn't multicast Fun!?!?!
That last statement was unnecessary, I know...
It's just a side effect of the cerebral hemmoraging due to
banging my head too much making room for this stuff :)
~M
>>> "ccie2be" <ccie2be@nyc.rr.com> 1/13/2005 3:52:44 PM >>>
Greetings Mark,
Thanks for your input. I think you're right (even though I was running
BSR, not auto-rp).
Here are the 2 lines again (for anyone just now seeing this thread).
r1#sh ip pim rp
Group: 225.25.25.25, RP: 150.1.1.1, v2, next RP-reachable in 00:00:47
Group: 232.32.32.32, RP: 150.1.2.2, v2, uptime 01:18:09, expires
00:02:09
Could we summarize why these 2 lines of output are different this way?
The 1st line says, "Me, R1, and RP for group X will send out another
rp-announcement in 47 seconds.
While the 2nd line says, "Me, R1 heard that R2 is RP for group Y. If I
don't get a re-confirmation in 2:09 minutes, I'll
throw out the info."
What do ya think?
Tim
----- Original Message -----
From: Mark Lasarko
To: ccielab@groupstudy.com ; ccie2be@nyc.rr.com
Sent: Thursday, January 13, 2005 12:44 PM
Subject: Re: mcast
Greetings Tim,I believe this indicates the time remaining until
the router will send an RP-Reachable message
(one minute by default), which would make sense
in this example as on r1 it only applies to the
150.1.1.1 address. It's seen on a router only if
the router is an RP for that multicast group.I was curious about the
default interval
and I stumbled upon this:"R1 receives the RP-reachable message for
group
239.255.0.1 and updates its expiration timer for RP.
This exchange repeats itself once a minute by default
and refreshes its multicast forwarding
state..."http://www.cisco.com/warp/public/105/57.htmlNow how can we
tweak this?3725_Rt(config)#ip pim send-rp-announce fastEthernet 0/0
scope 1 interval ?
<1-16383> number of secondsWith a default of 60?
Can someone confirm this is correct??~M
>>> "ccie2be" <ccie2be@nyc.rr.com> 1/12/2005 3:53:05 PM >>>
Hi guys,
What does this mean, next RP-reachable in 00:00:47, as shown below?
r1#sh ip pim rp
Group: 225.25.25.25, RP: 150.1.1.1, v2, next RP-reachable in 00:00:47
Group: 232.32.32.32, RP: 150.1.2.2, v2, uptime 01:18:09, expires
00:02:09
I've been having massive problems with the mcast config of iewb lab 15,
so I'm
trying to figure out
how to interpret some of the output from various show commands better.
TIA, Tim
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