From: Jason Madsen (madsen.jason@gmail.com)
Date: Fri Jul 11 2008 - 13:39:03 ART
here's some device output of a device using sparse-mode and then
sparse-dense-mode with completely default settings:
R0#sho run | s pim
ip pim sparse-mode
ip pim sparse-mode
ip pim sparse-mode
R0#sho ip multi
Multicast Routing: enabled
Multicast Multipath: disabled
Multicast Route limit: No limit
Multicast Triggered RPF check: enabled
*Multicast Fallback group mode: Sparse
*R0#
R0#sho run | s pim
ip pim sparse-dense-mode
ip pim sparse-dense-mode
ip pim sparse-dense-mode
R0#sho ip multi
Multicast Routing: enabled
Multicast Multipath: disabled
Multicast Route limit: No limit
Multicast Triggered RPF check: enabled
*Multicast Fallback group mode: Dense*
R0#
Jason
On Fri, Jul 11, 2008 at 10:27 AM, Jason Madsen <madsen.jason@gmail.com>
wrote:
> I think DM fallback is just for sparse-dense-mode, right?
>
> On Fri, Jul 11, 2008 at 10:23 AM, David Lonnie <david.lonnie@gmail.com>
> wrote:
>
>> Hi,experts:
>> So,is the following conclusion right?
>>
>> In a multicast domain,all routers configured with "ip pim
>> sparse-mode",without RP,C-RP,RP-agent and "ip pim autorp lisntener" command.
>> There is nothing different from ip pim dense-mode", is it? because ip pim
>> dm-fall is enable by default,and will fallback to dense-mode regardless of
>> the interface mode configuration.
>>
>> correct my if i am wrong.i am really confused.
>>
>>
>> Thanks in advance.
>>
>>
>> On Sat, Jul 12, 2008 at 12:06 AM, Jason Madsen <madsen.jason@gmail.com>
>> wrote:
>>
>>> I believe auto-rp listener uses dense mode only to contact the RP and
>>> Mapping Agent groups (224.0.0.39 and .40), while DM Fallback allows
>>> Dense mode (source to client) operation in the event of no RP.
>>>
>>> Jason
>>>
>>> On Fri, Jul 11, 2008 at 9:54 AM, David Lonnie <david.lonnie@gmail.com>
>>> wrote:
>>>
>>>> Hi,experts:
>>>> I am confused with these 2 commands.
>>>> ip pim dm-fallback is enable by default.and it means,it will fallback to
>>>> dense-mode,regardless of interface mode configuration.
>>>> if this is right.so why need to configure ip pim autorp listener when
>>>> using
>>>> sparse-mode?
>>>>
>>>> anybody can clarify for me?
>>>>
>>>>
>>>> Thanks in advance.
>>>>
>>>>
>>>> David
>>>>
>>>>
>>>>
>>>>
>>>> ip pim autorp listener
>>>>
>>>> To cause IP multicast traffic for the two Auto-RP groups 224.0.1.39 and
>>>> 224.0.1.40 to be Protocol Independent Multicast (PIM) dense mode
>>>> flooded
>>>> across interfaces operating in PIM sparse mode, use the ip pim autorp
>>>> listener command in global configuration mode. To disable this feature,
>>>> use
>>>> the *no* form of this command.
>>>>
>>>> ip pim dm-fallback
>>>>
>>>> To enable Protocol Independent Multicast (PIM) dense mode (DM) fallback,
>>>> use
>>>> the *ip pim dm-fallback* command in global configuration mode. To
>>>> prevent
>>>> PIM dense mode fallback and to block all multicast traffic for groups
>>>> not
>>>> specifically configured, use the *no* form of this command.
>>>>
>>>> *ip pim dm-fallback *
>>>>
>>>> *no ip pim dm-fallback *
>>>> Syntax Description
>>>>
>>>> This command has no arguments or keywords.
>>>> Command Default
>>>>
>>>> PIM dense mode fallback is enabled. That is, a multicast group in the
>>>> absence of rendezvous point (RP) information will fall to dense mode,
>>>> regardless of the interface mode configuration.
>>>>
>>>>
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