From: Bit Gossip (bit.gossip@chello.nl)
Date: Sun Mar 25 2007 - 09:47:14 ART
Hi Yemeni,
I would say that when something that shouldn't work, does work is as bad as
when something that should work doesn't .....:-)
Well, the solution/fix was already there in the form of 'ip pim nbma-mode'
The only way I could possibly think to explain how r1 can hear the prune from
r3, is that r2 does some sort of replication....
But this is undocumented afaik
This makes me very puzzled and feel like I have not grasp of the topic ;-(
Luca.
----- Original Message -----
From: Digital Yemeni
To: Bit Gossip
Cc: ccielab
Sent: Sunday, March 25, 2007 3:01 PM
Subject: Re: multicast very fundamental
Is this good or bad? initially, R1 was NOT hearing the prune message and
this was the problem that Cisco addressed. Maybe they have corrected this
problem in later release but it seems you're unhappy of the fix!! :D no?!
On 3/25/07, Bit Gossip <bit.gossip@chello.nl> wrote:
Group I am stuck for days on this very fundamental multicast
mechanics...
I noticed this strange thing while playing with the multicast task of
IEWB4-LAB02 and couldn't get to the bottom of it; then I gave up.
Now I have reproduced it in a very simple scenario, and the pb is still
there.
r1
|
|
r2 ----<
|
|
r3
*) Frame relay hub'n'spoke with r2=hub, only serial physical interfaces
*) Full reachability via OSPF
*) PIM-SM with r2=RP; multicast source=132.1.26.8 attached to r2 f1/0
for group 228.28.28.28; receivers attached to r1 and r3
*) it works fine, all receivers get the group
And now the funny part !!
*) there is no layer 2 connectivity between r1 and r3 as you can see
below; but still r1 HEARS the prune from r3 and OVERRIDES it !!!!!!!!
How is it possible ??????
When r3 leaves the group this is the pim debug on r1:
PIM(0): Received v2 Join/Prune on Serial0/0 from 132.1.0.3, not to us
PIM(0): Prune-list: (*, 228.28.28.28) RP 150.1.2.2
PIM(0): Set join delay timer to 1000 msec for (150.1.2.2/32,
228.28.28.28) on Serial0/0
PIM(0): Building Periodic (*,G) Join / (S,G,RP-bit) Prune message for
228.28.28.28
PIM(0): Insert (*,228.28.28.28 ) join in nbr 132.1.0.2's queue
PIM(0): Building Join/Prune packet for nbr 132.1.0.2
This one is a classical example mentioned in Cisco doc, where PIM-SM
goes into trouble because one spoke cannot hear the prune from another
one and then override it; but in my lab it doesn't seem to happen....
Below this line config and show's
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
r1
ip multicast-routing
interface Loopback0
ip address 150.1.1.1 255.255.255.0
ip pim sparse-dense-mode
ip igmp join-group 228.28.28.28
!
interface FastEthernet0/0
ip address 132.1.17.1 255.255.255.0
ip pim sparse-mode
speed 100
full-duplex
!
interface Serial0/0
ip address 132.1.0.1 255.255.255.0
ip pim sparse-mode
encapsulation frame-relay
ip ospf network point-to-multipoint
no fair-queue
clock rate 64000
frame-relay map ip 132.1.0.2 102 broadcast
no frame-relay inverse-arp
!
router ospf 1
router-id 150.1.1.1
log-adjacency-changes
passive-interface default
no passive-interface Serial0/0
network 132.1.0.1 0.0.0.0 area 0
network 132.1.17.1 0.0.0.0 area 0
network 150.1.1.1 0.0.0.0 area 0
!
ip pim rp-address 150.1.2.2
ip pim spt-threshold infinity
--------
r1#show frame-relay map
Serial0/0 (up): ip 132.1.0.2 dlci 102(0x66,0x1860), static,
broadcast,
CISCO, status defined, active
r1#ping 224.0.0.2
Type escape sequence to abort.
Sending 1, 100-byte ICMP Echos to 224.0.0.2, timeout is 2 seconds:
Reply to request 0 from 132.1.17.7 , 4 ms
Reply to request 0 from 132.1.0.2, 88 ms
Reply to request 0 from 150.1.1.1, 4 ms
r1#show ip mroute 228.28.28.28
IP Multicast Routing Table
(*, 228.28.28.28), 00:49:48/00:02:58, RP 150.1.2.2, flags: SCL
Incoming interface: Serial0/0, RPF nbr 132.1.0.2
Outgoing interface list:
Loopback0, Forward/Sparse-Dense, 00:47:47/00:02:39
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
r2
ip multicast-routing
!
interface Loopback0
ip address 150.1.2.2 255.255.255.0
ip pim sparse-mode
!
interface FastEthernet1/0
ip address 132.1.26.2 255.255.255.0
ip pim sparse-mode
no ip mroute-cache
duplex full
!
interface Serial4/0
ip address 132.1.0.2 255.255.255.0
ip pim sparse-mode
encapsulation frame-relay
ip ospf network point-to-multipoint
no ip mroute-cache
serial restart-delay 0
frame-relay lmi-type cisco
!
router ospf 1
router-id 150.1.2.2
log-adjacency-changes
passive-interface default
no passive-interface Serial4/0
network 132.1.0.2 0.0.0.0 area 0
network 132.1.26.2 0.0.0.0 area 0
network 150.1.2.2 0.0.0.0 area 0
!
ip pim rp-address 150.1.2.2
--------
r2#show frame-relay map
Serial4/0 (up): ip 132.1.0.1 dlci 201(0xC9,0x3090), dynamic,
broadcast,
CISCO, status defined, active
Serial4/0 (up): ip 132.1.0.3 dlci 203(0xCB,0x30B0), dynamic,
broadcast,, status defined, active
r2#ping 224.0.0.2
Type escape sequence to abort.
Sending 1, 100-byte ICMP Echos to 224.0.0.2, timeout is 2 seconds:
Reply to request 0 from 150.1.2.2, 1 ms
Reply to request 0 from 132.1.0.1, 76 ms
Reply to request 0 from 132.1.0.3, 64 ms
r2#show ip mroute 228.28.28.28
IP Multicast Routing Table
(*, 228.28.28.28), 01:01:35/00:03:10, RP 150.1.2.2, flags: S
Incoming interface: Null, RPF nbr 0.0.0.0
Outgoing interface list:
Serial4/0, Forward/Sparse, 00:50:51/00:03:10
(132.1.26.8, 228.28.28.28), 00:01:18/00:03:22, flags: T
Incoming interface: FastEthernet1/0, RPF nbr 0.0.0.0
Outgoing interface list:
Serial4/0, Forward/Sparse, 00:01:18/00:03:10
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
r3
ip multicast-routing
!
interface Loopback0
ip address 150.1.3.3 255.255.255.0
!
interface FastEthernet3/0
ip address 132.1.33.3 255.255.255.0
ip pim sparse-mode
ip policy route-map T8.2
duplex full
!
interface Serial4/0
bandwidth 512
ip address 132.1.0.3 255.255.255.0
ip pim sparse-mode
encapsulation frame-relay
ip ospf network point-to-multipoint
serial restart-delay 0
frame-relay map ip 132.1.0.2 302 broadcast
no frame-relay inverse-arp
!
router ospf 1
router-id 150.1.3.3
log-adjacency-changes
passive-interface default
no passive-interface Serial4/0
network 132.1.0.3 0.0.0.0 area 0
network 132.1.3.3 0.0.0.0 area 0
network 132.1.33.3 0.0.0.0 area 0
network 150.1.3.3 0.0.0.0 area 0
!
ip pim rp-address 150.1.2.2
ip pim spt-threshold infinity
-----------
r3#show frame-relay map
Serial4/0 (up): ip 132.1.0.2 dlci 302(0x12E,0x48E0), static,
broadcast,
CISCO, status defined, active
r3#ping 224.0.0.2
Type escape sequence to abort.
Sending 1, 100-byte ICMP Echos to 224.0.0.2, timeout is 2 seconds:
Reply to request 0 from 132.1.0.2, 116 ms
r3#show ip mroute 228.28.28.28
IP Multicast Routing Table
(*, 228.28.28.28), 00:02:13/00:02:59, RP 150.1.2.2 , flags: SCL
Incoming interface: Serial4/0, RPF nbr 132.1.0.2
Outgoing interface list:
FastEthernet3/0, Forward/Sparse, 00:02:13/00:02:33
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--
Best Regards!
Digital, CCIE# to be assigned by Cisco when it collects enough $$ out of me!
:p
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