02-16-2009 01:37 PM - edited 03-06-2019 04:04 AM
i have simple hub and spoke tpology
the hub configured with to map statments of frame-relay point to both spoks with broadcast word
spoks has one with broadcast word for the hub other one only map the other spok and point it to the local DLCI
simple and everyone ping each other
now i run ospf over this network
and we know by defualt it is non-broadcast then i add the neighbor command on the hub point to each spoke
now evrthing works fine as well
Multicast
the hub is the RP and discovery comand entered as well
one router behind the sopks joined an igmp group
each router run pim sapre-mode and the hub in addition to that has pim nbma-mode
the problem is
everything OK every on ping the joined igmp group
ecept from the other spoke
when i ping forst packet get replay and anything after first packet NO
in the hum and the RP as well what i noticed
first ping there is outgoing interface for that spoke for the subsequent the outgoing interface shows as NULL !!!!
however when i run ospf as poin-to-multipoint works fine
with EIGRP the same issue (split-horizon disabled)
any Idea Guys !!!
02-16-2009 01:47 PM
Hello Marwan,
give a look at the following chapter from 12.4 multicast config guide
ip pim nbma-mode command can help
Hope to help
Giuseppe
02-16-2009 02:29 PM
Please post the output from:
show ip mroute
show ip pim rp mapping
show ip pim interface
show ip pim neigh
show ip os neigh
from the 3 routers.
__
Edison.
02-16-2009 02:42 PM
hi Edison
i dont have this output now
but i can give what you looking for frothis show comands
for mroute
spoke show the outgoing interfac as the FR interface
but the issue with the hub
although it has ip pim nbma-mode
as i mention firt time with show ip mroute
the hub shows
for the sopke i ping FROM the ip address in S and the destination ijmp grup in the G
and the incoming and outgoing interfaces correct
howver fter first success ping
on the hub the outgoing interface for this spok ( the one i ping from ) the outgoing interface shown as NULL
here why i am confsed
even if i put he command ip pim spt-thrshould infinity no lck !!!
for mappping they all see the hub as the RP
becuase i did in the spoke autorp listner !!!
if you need anymore details let me know ?
but why the first packet go then the outgoing interface in the hub change to NULL ??
thanks again
02-16-2009 03:00 PM
I can't duplicate your problem here and it could be an underlying problem with the IGP.
Here is my lab, R1 (Hub) R2 and R3 (Spokes)
R1:
interface Serial1/0
ip address 192.168.123.1 255.255.255.0
ip pim nbma-mode
ip pim sparse-mode
encapsulation frame-relay
no ip mroute-cache
serial restart-delay 0
frame-relay map ip 192.168.123.2 102 broadcast
frame-relay map ip 192.168.123.3 301 broadcast
no clns route-cache
R2:
interface Serial1/0
ip address 192.168.123.2 255.255.255.0
ip pim sparse-mode
encapsulation frame-relay
ip ospf priority 0
serial restart-delay 0
frame-relay map ip 192.168.123.3 201
frame-relay map ip 192.168.123.1 201 broadcast
no clns route-cache
R3:
interface Serial1/0
ip address 192.168.123.3 255.255.255.0
ip pim dr-priority 0
ip pim sparse-mode
encapsulation frame-relay
ip ospf priority 0
no ip mroute-cache
serial restart-delay 0
frame-relay map ip 192.168.123.2 103
frame-relay map ip 192.168.123.1 103 broadcast
no clns route-cache
end
__________
I made sure R1 was the DR for that segment by changing the OSPF priority on the spokes.
I configured R1 with Auto-RP by using loopback and here are the mappings all routers:
PIM Group-to-RP Mappings
Group(s) 224.0.0.0/4
RP 150.1.1.1 (?), v2v1
Info source: 150.1.1.1 (?), elected via Auto-RP
Uptime: 00:39:54, expires: 00:02:49
_____
Now, I'm going to do a join on R3 and do a ping from R2..
R3(config)#int lo0
R3(config-if)#ip igmp join-group 229.3.3.3
R3(config-if)#do show ip mroute 229.3.3.3
(*, 229.3.3.3), 00:00:07/00:02:52, RP 150.1.1.1, flags: SJCL
Incoming interface: Serial1/0, RPF nbr 192.168.123.1
Outgoing interface list:
Loopback0, Forward/Sparse, 00:00:07/00:02:52
_____
Verify the join was sent to the RP:
R1#sh ip mroute 229.3.3.3
(*, 229.3.3.3), 00:01:42/00:02:47, RP 150.1.1.1, flags: S
Incoming interface: Null, RPF nbr 0.0.0.0
Outgoing interface list:
Serial1/0, 192.168.123.3, Forward/Sparse, 00:01:42/00:02:47
______
Ping from the other spoke:
R2#ping 229.3.3.3 repeat 10
Type escape sequence to abort.
Sending 10, 100-byte ICMP Echos to 229.3.3.3, timeout is 2 seconds:
Reply to request 0 from 192.168.123.3, 152 ms
Reply to request 1 from 192.168.123.3, 92 ms
Reply to request 2 from 192.168.123.3, 128 ms
Reply to request 3 from 192.168.123.3, 136 ms
Reply to request 4 from 192.168.123.3, 140 ms
Reply to request 5 from 192.168.123.3, 132 ms
Reply to request 6 from 192.168.123.3, 116 ms
Reply to request 7 from 192.168.123.3, 104 ms
Reply to request 8 from 192.168.123.3, 192 ms
Reply to request 9 from 192.168.123.3, 124 ms
_______
Check the hub mroute table now:
R1#sh ip mroute 229.3.3.3
(*, 229.3.3.3), 00:03:54/00:02:32, RP 150.1.1.1, flags: S
Incoming interface: Null, RPF nbr 0.0.0.0
Outgoing interface list:
Serial1/0, 192.168.123.3, Forward/Sparse, 00:03:54/00:02:32
(192.168.123.2, 229.3.3.3), 00:01:04/00:02:54, flags: T
Incoming interface: Serial1/0, RPF nbr 0.0.0.0
Outgoing interface list:
Serial1/0, 192.168.123.3, Forward/Sparse, 00:01:04/00:01:55
HTH,
__
Edison.
02-16-2009 03:50 PM
Hi Edison
first Thank you for this config i will give it try tonight
however i did the same as u did mostly except i did not put
th following command on the hub inteerface
no ip mroute-cache
dose this make deffrence ??
also for rp in the hub i did it like
int lo0
ip pim spare-mode
ip pim send-rp-announce looback 0 secope 16
ip pim send-rp-discovery loopback 0 scope 16
in addition to that
IF I DONTPUT the AUTORP LISTNER on SPOKES they will not know about the RP
becuase u know there is know dense ???!!!
let me know if something missing
as i mentioned
why it wor when i have it as ospf poin-to-multipoint
but with non-broadcast and eigrp Not ??!!!
Thanks again
02-16-2009 03:56 PM
however i did the same as u did mostly except i did not put
th following command on the hub inteerface
no ip mroute-cache
dose this make deffrence ??
No, I did it for the debugs.
It works the same w/o it.
IF I DONTPUT the AUTORP LISTNER on SPOKES they will not know about the RP
becuase u know there is know dense ???!!!
Correct.
let me know if something missing
Try forcing the hub to be the PIM DR as well as the OSPF DR.
as i mentioned
why it wor when i have it as ospf poin-to-multipoint
but with non-broadcast and eigrp Not ??!!!
point-to-multipoint does not use the concept of the DR and that's the reason I told you, something is wrong with the underlying IGP.
I'll check with EIGRP later on and see if I can duplicate the problem.
__
Edison.
02-16-2009 04:13 PM
Try forcing the hub to be the PIM DR ?
how can this be done and what is the defrence from from RP role ?
by the way sometimes they mentioned about Mapping agent MA is that means the router with the discovery command ??
which we have it in my case on the same router !!??
also if i have question say this router need t be the group maping
sometimes i see it solved as above with discovery and filltering if required HOEVEVER somtimes i see it used as BSR ??
why and how i can kno which one to use
Thanks again mate
02-16-2009 04:13 PM
02-16-2009 04:18 PM
i will try it tonight :)
by the way why u did used
neighbor 192.168.123.3 Serial1/0
neighbor 192.168.123.2 Serial1/0
while we done need to send roting as unicast
it should work without it right ?
02-17-2009 02:37 AM
Hi Edison
i have attached the router config i have tried th ething u have mentioned but no luck
R1 hub
R2 and R3 spokes
R4 just a router connected to R3 and has defualt route to R3 and i joined it to an ijmgp group for ping test
first ping from R2 go and the subsequent NOT
other routers ping normally
also if u see in router 1 the outgoing interface for R2 to the gorup i use is Null
in router 4 for all other router shows null but they can ping except R2
any idea will be helpful cause i got confused all configred ok but not luck !!
thank you
02-17-2009 07:08 AM
02-17-2009 01:19 PM
hi Edison
based on my config it should work i mean the config is ok ?
because i just get confused about it
about the comment bellow from mohamed
the RPF not the issue becuase it is just simple hub and spoke
even not full meshed network
and the traffic should go R1 !!!
Thanks Edison, by the way if you think my config OK becuase as i told you only with OSPF non-broadcast and eigrp dose not work !!
do you think becuase i use GNS3 for this ?!
Thanks again
02-17-2009 01:48 PM
I will let Mohamed discuss his logic on RPF since I don't see any RPF problem on the topology.
As you see from my configs, EIGRP & OSPF worked identically.
BTW, my lab was also done on GNS3, using 7200 routers and 12.2(25)S15 image.
HTH,
__
Edison.
02-17-2009 03:06 AM
Marwan,
what is 225.0.0.1 represets? If you are Pinging from IGMP group assigned on router-2 interface to the Source which should be 150.x.x.x should be successful and its only a source of check.
The RPF method state the following:
If the incoming Interface for the multicast packet doesnt lead back to the source which is (R1) in your case,then the RPF fails and multicast packet is dropped.
Make sure that R1 source of the multicast packet is reachable via the same Interface of the recieved incoming multicast packet. (You will need to source the Ping from that Interface) OR you have to configure the following:
IP mroute "Source addresss" "subnet Mask" exit interface.
HTH
Mohamed
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