Re: draft-kou-ospf-immediately-replying-hello-00.txt

[Acee Lindem <[e-mail]>]

Zengjie Kou wrote:

>Hi, Acee,
>    You are right, immediate hello does not provide the mechanism of detecting link down fast. But, immediate hello improve to discover neighbors when interface goes down then up. In practice, the requirement is needed.
>  
>
Hi Zengjie,

Speaking strictly in terms of state machines, it seems the interface 
would lose it's DR/BDR state
when it goes down (and cannot send a hello). Wouldn't this scenario be 
better handled
by the empty hello many OSPF implementations send when an interface 
first comes up?

Thanks,
Acee

>Thanks,
>Zengjie
>
>----- Original Message ----- 
>From: "Acee Lindem" <[e-mail]>
>To: <[e-mail]>
>Sent: Monday, February 20, 2006 11:15 PM
>Subject: Re: draft-kou-ospf-immediately-replying-hello-00.txt
>
>
>  
>
>>Hi Zengjie,
>>
>>Zengjie Kou wrote:
>>
>>    
>>
>>>Hi,Acee,
>>>   If a router interface whose role is changed(e.g.DR goes down), the router will notify all routers about the change by immediate hello.
>>> 
>>>
>>>      
>>>
>>This is only when the DR/BDR knows that it is going down or the case 
>>where the router
>>priority is set to 0.
>>
>>For a router becoming DR/BDR, all the routers should elect the same DR/BDR
>>so I don't see how it helps.
>>
>>Thanks,
>>Acee
>>
>>    
>>
>>>After all router get the change, election will be reprocessed. In contrast to normal hello, immediate hello avoid the backupSeen.
>>>Namely, improving convergence.
>>>
>>>Thanks a lot,
>>>Zengjie
>>>
>>>----- Original Message ----- 
>>>From: "Acee Lindem" <[e-mail]>
>>>To: <[e-mail]>
>>>Sent: Saturday, February 18, 2006 5:17 AM
>>>Subject: draft-kou-ospf-immediately-replying-hello-00.txt
>>>
>>>
>>> 
>>>
>>>      
>>>
>>>>Hi Zengjie,
>>>>
>>>>Under what situations does having the router who changed to/from
>>>>DR/BDR improve convergence (section 6.2)? Since DR/BDR election
>>>>is a distributed algorithm dependent on the calculating routers state, it
>>>>seems this won't help in all that many cases.
>>>>
>>>>Thanks,
>>>>Acee
>>>>   
>>>>
>>>>        
>>>>
>>> 
>>>
>>>      
>>>
>
>  
>