multicast over frame-relay issue !!

[Marwan ALshawi]

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 !!!

[Mohamed Sobair]

Edison,

The original poster has claimed that he can perform ping from all routers except R2? and I have suggested the following:

Since all routers recieved their mapping information and they have route back to the RP, then the possible cause is the Source of the ICMP packet from R2 is not the incoming interface for the multicast packet. I have also suggested him to configure Static IGMP Group on one of R2's Ethernet Interface and perform normal ping sourced from the serial Interface while making sure the outgoing interface for the ICMP packet is an RPF interface.

Another question is why Marwan is performing ping to 225.x.x.x Group from R2? what is this going to accomplish?

Mohamed

[Marwan ALshawi]

Hi Mohamed

i do this for CCIE LAB !

and if it is RPF problem then in this case i could not have been ble to get any response or reply when i ping

while i do have first packet with replay and the others failes which exclude RPF!

Edison i use the same as yours but not sure what IOS version exactly i will check tonight

by the way my config same as yours then can i consider my config right? and the logic i do my multicast over FR with NBMA is right as well ??

one more thing why u used neighbor command with eigrp without it it should work as well ??

thank you

[Edison Ortiz]

Marwan,

I tried to match your config as close as possible and I'm unable to duplicate what you are seeing.

Per your config output, you get the join:

From R3

(*, 225.1.1.1), 00:13:38/stopped, RP 150.1.1.1, flags: S

Incoming interface: Null, RPF nbr 0.0.0.0

Outgoing interface list:

Serial1/0, 10.1.1.3, Forward/Sparse, 00:13:12/00:02:35

Then the ip pim nbma-mode isn't doing what is supposed to do then the router prunes the S,G:

(10.1.1.2, 225.1.1.1), 00:00:05/00:02:55, flags: PT

Incoming interface: Serial1/0, RPF nbr 0.0.0.0

Outgoing interface list: Null

With my config, I get the join from R3:

(*, 225.1.1.1), 00:02:47/00:02:43, 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, 00:02:47/00:02:43

and the nbma mode kicks in by listing S0/1 with the unicast information from each router of the link:

(192.168.123.2, 225.1.1.1), 00:01:21/00:02:45, flags: T

Incoming interface: Serial1/0, RPF nbr 0.0.0.0

Outgoing interface list:

Serial1/0, 192.168.123.3, Forward/Sparse, 00:01:21/00:01:39

As you can see, the ping is coming from R2 to R3.

________

As for the EIGRP neighbor statement, it does not factor into problem. It works the same with or without.

__

Edison.

[Marwan ALshawi]

Ok upon this

i can guess it is more IOS issue as said rather than config

becuase my config since first time sae as yours.. and with Mcast as you know there is no much config it just concepts need to be applied correctly

i think i need to change the IOS otherwise it will not work for ever becuase no way to configure it other than this way right ..!!

thanks for you help

[Edison Ortiz]

Marwan,

I have good news. I was able to duplicate your problem.

Try creating a loopback in R2.

I deleted the loopback in R2 and the hub pruned the S,G like in your lab.

Very interesting and I wonder if this is a GNS3 behavior. I don't have real routers to test right now but this is very strange.

__

Edison.

[Edison Ortiz]

Further testing...

It seems the behavior (at least on GNS3), you need to have more than one Layer3 interface in up/up state if you have the router acting as a Mcast Server.

I did the opposite and setup R2 as the Mcast client with R3 being the server.

R3 is connected to R4 so it has two Layer3 links hence there is no need for loopback.

Multicast is working fine on this scenario.

__

Edison.

[Marwan ALshawi]

Hi Edison

really interesting and strange !!!!

i will try it

by the way do i expect it in the CCIE LAB as well :)

i think this is only in gns3 because i have never seen a document or bock mentioned about this point !!

i think the copy right for this will be yours :)

thanks again i will let you know after try it

by the way i have to make this loopbackaddress Mcast enabled ??

[Edison Ortiz]

You won't expect that kind of behavior in the CCIE lab as most routers will have multiple L3 interfaces.

The fact that we created a router with just one interface and in your case without a loopback, created the issue.

Routers aren't that good for Mcast server/client function, their function is to be Mcast routers.

No, you don't need to enable PIM on the loopback.

HTH,

__

Edison.

[Marwan ALshawi]

actually i did what you have notced

but it was good to some extend

ping from R3 to R2 as R2 joind a group dose the ping ffrom 8 i get about 3 replyes whihc means ok but somthing wrong maybe with GNS3 !!!!

from R2 to R3 or R4 the same problem

anyway i think this is the only way to configure the Mcast over FR

thank you for your help

[Marwan ALshawi]

Hi Edison

i have somthing confused me

in multicast section

i see in internetworkexpert workbooks sometimes when the question say this router will be resposible for RP to group maping

they solved as RP agent with discovery comaand

and in others useing BSR

when i have to use BSR

thanks

[Edison Ortiz]

Why people fail in the CCIE Lab is mostly due to interpreting what is asked.

It's very hard to tell you when to choose one technology over the other without reading the whole workbook.

Often the answer is tied to another underlying technology that is part of that Lab.

Other times, the answer is there with some hints like:

Use PIM version 2.0

or

Use PIM version 1.5

or

Use PIM described on RFC 5059

Understand?

I'm afraid, you need to practice and practice. There isn't a straight answer to this type of query.

__

Edison.

[Marwan ALshawi]

Hi Edison

i agree with you

because with multicasting and IPV6 there is no alot practice i think i need to cover all posible case as i can

for example the hints you have mentioned very nice

thats why i need to know what hints should i see to use this one or that one

for example maybe the type of network effect the choice with frame-relay and ospf

we need to see what frame-relay we hav P2P or P2multipoint and so on then we can decied

i am aware aboutthat thanks

but for example i will give now somthing i am thinking about confusing HSRP solusion

there is to labs in he IE workbook

both of them asked to track the connection to the FR cloud OK

buut one of them solved with normaway which is track interface serial x/x

the other one solved in a way i liked it

lets say the 2 spokes are HSRP peeers and they have to track the connection to the FR cloud i mean the active one as above

but what they did

the created a tunnel interface between the active HSRP(spoke) and the hub router and they put the tracked interface as the tunnel

it is interesting one i tried it and worked fine

but which one rom your experince will be considered the right one ( or both works)

the question ask the same and the case mostly the same

thanks again :)