Niviya,

>> "When a multicast-capable interface becomes enabled, the node MUST join the 
>> all-nodes multicast address on that interface, as well as the solicited-    
>> node multicast address corresponding to each of the IP addresses assigned to 
>> the interface."
>> Any idea What does this statement mean?

[Shree] If the hosts on link are connected through a multicast aware device 
(e.g. switch with MLD proxy),  
these messages are intended to  inform the switch that host is interested in 
receiving packets destined 
to all -nodes and solicited node multicast address. 


>> Why the node is sending unsolicited NA message ( with source as "link-local 
>> address" & destination as "all-node multicast address").
>> I am expecting only one unsolicited NA message( with source as "ipv6 global 
>> address" & destination as "all-node multicast address").  
>> I am not at all changing the link-local address and the link-local address 
>> is already active on the interface.


[Shree] If you are assigning an address the node should send out Neighbor 
solicitation 
 as part of Duplicate Address Detection(source as unspecified address and 
destination as solicited node multicast address).

>From what you are seeing it looks like link layer address is getting changed, 
>one way to verify it is through the override flag and source link layer 
>address option
n unsolicited neighbor advertisement. Before and after you apply the ipv6 
address.

--
Shree


From: [email protected] [mailto:[email protected]] On Behalf Of niviya 
vijayan
Sent: Wednesday, April 21, 2010 10:59 AM
To: Suresh Krishnan
Cc: [email protected]
Subject: Re: RFC 4861:-Link-Local address joining all-node multicast group.

Hi Suresh,
 
RFC 4861 Statement:- 7.2.1.Interface Initialization

"When a multicast-capable interface becomes enabled, the node MUST join the 
all-nodes multicast address on that interface, as well as the solicited-    
node multicast address corresponding to each of the IP addresses assigned to 
the interface."
Any idea What does this statement mean?
 
For the second query:-
 
I didnt change the MAC address of the card. I tried creating a new ipv6 address 
on the interface and I have seen these two unsolicited NA messages.My question 
is , Why the node is sending unsolicited NA message ( with source as 
"link-local address" & destination as "all-node multicast address").I am 
expecting only one unsolicited NA message( with source as "ipv6 global address" 
& destination as "all-node multicast address").  I am not at all changing the 
link-local address and the link-local address is already active on the 
interface. 
 
Regards,
Niviya

 
On Wed, Apr 21, 2010 at 4:22 AM, Suresh Krishnan <[email protected]> 
wrote:
Hi Niviya, 


On 10-04-20 05:09 AM, niviya vijayan wrote:
Hi Suresh,
 Thanks for your reply. I have a doubt on your answer.
 As per your comments, there can be two MLD report msg which will join the node 
in solicited multicast group . But in the RFC 4861, they have mention there 
should be a join request to all node multicast group.

As described in section 6 of RFC3810 MLD reports are not sent for the all-nodes 
multicast address

"  The link-scope all-nodes multicast address, (FF02::1), is handled as
  a special case.  On all nodes -- that is all hosts and routers,
  including multicast routers -- listening to packets destined to the
  all-nodes multicast address, from all sources, is permanently enabled
  on all interfaces on which multicast listening is supported.  No MLD
  messages are ever sent regarding neither the link-scope all-nodes
  multicast address, nor any multicast address of scope 0 (reserved) or
  1 (node-local)." 

.
 
RFC 4861 Statement:- 7.2.1.Interface Initialization

"When a multicast-capable interface becomes enabled, the node MUST join the 
all-nodes multicast address on that interface, as well as the solicited-    
node multicast address corresponding to each of the IP addresses assigned to 
the interface."

  I have one more query  regarding NA messages.
 While creating ipv6 address on an interface, unsolicited NA messages will be 
sent to all node multicast address to inform all other nodes in the network. 
When i tried this scenario , I have seen two NA messages.
 1) source as ipv6 address and destination as ipv6 all node address.
2) source as link-local address and destination as ipv6 all node address.
 My question is, whenever there is a change in ipv6 address on a node, both 
these 2 NA messages will propogate through the network?
or is it really required to share about the link-local address as we are not at 
all changing the ipv6 link-local address.?

It is unclear what the circumstances are. Specifically, what action did you 
perform that resulted in these messages? Did you change the MAC address of the 
card?
 
Hi Suresh,
 
I didnt change the MAC address of the card. I tried creating a new ipv6 address 
on the interface and I have seen these two unsolicited NA messages.My question 
is , Why the node is sending unsolicited NA message ( with source as 
"link-local address" & destination as "all-node multicast address").I am 
expecting only one unsolicited NA message( with source as "ipv6 global address" 
& destination as "all-node multicast address").  I am not at all changing the 
link-local address and the link-local address is already active on the 
interface. 

Cheers
Suresh



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