Revised:Multicast Helper Map configuration(Difference between

From: ??? (seajay76@nate.com)
Date: Fri Jan 06 2006 - 15:30:26 GMT-3


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Little mistake...

Disregard the previous mail, and please read this one.
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Dear members;

While I was studying about multicast helper-map,

I found a lot of differences between the Cisco Univercd and the Cisco Press book.

I captured both the configurations as well as mine.

So, if anyone knows well about multicast, please help me out.

Here is the topology.

--------------------------------------------------------------------------------

Broadcast SRC(10.1.1.10)+----+E0:10.1.1.1[RTR-A]S0+----MULTICAST CLOUD....

...MULTICAST CLOUD----+S0[RTR-B]E0:10.2.2.1+---Non-MC Receiver(10.2.2.10)

--------------------------------------------------------------------------------

And the Configurations

The differences are marked with (*).

--------------------------------------------------------------------------------

### 12.2 Multicast Configuration Guide ###

- http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fipr_c/ipcpt3/1cfmulti.htm#wp1003511
- Eth1 is in the example of CCO is changed to S0 in the example here.

[RTR-A]

int e0
 ip directed broadcast
 ip multicast helper-map broadcast 224.5.5.5 100
 ip pim dense-mode
!
access-list 100 permit udp any any 4000
!
ip forward-protocol udp 4000

[RTR-B]

int e0
 ip directed-broadcast
 ip multicast helper-map 224.5.5.5 10.2.2.255 100
 ip pim dense-mode
!
access-list 100 permit udp any any 4000
!
ip forward-protocol udp 4000

!!! This is what Williamson tells us to be careful about.
    The 'ip multicast helper-map' command shouldn't be configured,he says,
    on an outgoing interface where non-multicast-capable receivers reside.
    But the configuration guide tells us to do so!!!

### Developing IP Multicast Networks(by Beau Williamson) ###

[RTR-A]

int e0
 ip directed-broadcast
 ip multicast-helper broadcast 224.5.5.5 100
!
access-list 100 permit any any udp 4000
!
ip forward-protocol udp 2000

[RTR-B]

int s0
 ip multicast helper-map 224.5.5.5 10.2.2.255 100
 ip igmp join-group 224.5.5.5(automatically configured by IOS)
!
int e0
 ip directed-broadcast
!
access-list 100 permit udp any any eq 4000

### My Solution ###

[RTR-A]

int e0
     --> I don't think this interface is a multicast interface.
 ip directed-broadcast
     --> Since the interface should process the broadcast
 ip multicast helper-map broadcast 224.5.5.5 100
     --> Since the router should translate broadcast into multicast
!
access-list 100 permit udp any any 4000
!
ip forward-protocol udp 4000

[RTR-B]

int s0
 ip multicast helper-map 224.5.5.5 10.2.2.255 100
     --> Since the router should translate the multicast into broadcast
 ip igmp join-group 224.5.5.5(automatically configured by IOS)
 ip pim dense-mode
     --> Since this interface is included in the multicast cloud
int e0
     --> I don't think this interface is a multicast interface.
 ip directed-broadcast
     --> Since this interface should process broadcast
!
access-list 100 permit udp any any 4000
!
ip forward-protocol udp 4000

--------------------------------------------------------------------------------
> ip forward-protocol udp 4000
>
> [RTR-B]
>
> int s0
> ip directed-broadcast
> ip multicast helper-map 224.5.5.5 10.2.2.255 100
> ip pim dense-mode
> !
> access-list 100 permit udp any any 4000
> !
> ip forward-protocol udp 4000
>
>
> ### Developing IP Multicast Networks(by Beau Williamson) ###
>
> [RTR-A]
>
> int e0
> ip directed-broadcast
> ip multicast-helper broadcast 224.5.5.5 100
> !
> access-list 100 permit any any udp 4000
> !
> ip forward-protocol udp 2000
>
> [RTR-B]
>
> int s0
> ip multicast helper-map 224.5.5.5 10.2.2.255 100
> ip igmp join-group 224.5.5.5(automatically configured by IOS)
> !
> int e0
> ip directed-broadcast
> !
> access-list 100 permit udp any any eq 4000
>
> ### My Solution ###
>
> [RTR-A]
>
> int e0
> --> I don't think this interface is a multicast interface.
> ip directed-broadcast
> --> Since the interface should process the broadcast
> ip multicast helper-map broadcast 224.5.5.5 100
> --> Since the router should translate broadcast into multicast
> !
> access-list 100 permit udp any any 4000
> !
> ip forward-protocol udp 4000
>
> [RTR-B]
>
> int s0
> ip multicast helper-map 224.5.5.5 10.2.2.255 100
> --> Since the router should translate the multicast into broadcast
> ip igmp join-group 224.5.5.5(automatically configured by IOS)
> ip pim dense-mode
> --> Since this interface is included in the multicast cloud
> int e0
> --> I don't think this interface is a multicast interface.
> ip directed-broadcast
> --> Since this interface should process broadcast
> !
> access-list 100 permit udp any any 4000
> !
> ip forward-protocol udp 4000
>
> --------------------------------------------------------------------------------
>
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