Re: [OSPF] Clarification of DR & BDR Processing in OSPFV3

[Acee Lindem <[e-mail]>]

Hi Thirumalvalavan, 
See inline. 
On Dec 27, 2011, at 6:46 AM, Thirumavalavan Periyannan wrote:

> Hi All,
>  
> I have a doubt in DR and BDR process in OSPFV3.
>  
> “   AllDRouters: 
>                      This multicast address has been assigned the value FF02::6.
>    Both the Designated Router and Backup Designated Router must be
>    prepared to receive packets destined to this address.  Certain
>    OSPF protocol packets are sent to this address during the
>    flooding procedure.”
>  
> RFC says, DR & BDR must be prepared to receive packets destined to FF02::6, Here is that Prepared means to say BDR needs
> to process the packet with destination address FF02::6 (ALLDRouters)?

Yes. This is somewhat implementation and network interface type specific but it implies that the packet will be received and passed to the OSPFv3 instance's receive queue. 
For example, on ethernet this implies that packets sent the Multicast MAC 33:33:00:00:00:06. 

>  
> In CISCO routers, BDR is not processing the packet with destination address “ALLDRouters”.
> But the same BDR when it receives an update packet with destination address as “ALLSPFRouters”, it is processing the packet.

The receiving OSPFv3 router should process all packets addressed to FF02::6. I'd advise you turn on some debugs on the both the sending and receiving OSPFv3 routers to determine whether or not the packet is being rejected. 

Hope this helps,
Acee

>  
> So I want a clarification of the above lines in the standard.
>  
> Regards,
> Thirumavalavan
> Consultant
> 
>