Re: [DNA] Revised FRD (Fast Router Discovery) I-D

[JinHyeock Choi <jinchoe@gmail.com>]

Dear Brett

> I don't quite understand this.  How can sending an RS to the AR, getting
> back an RA and then forwarding that RA to the MN be faster than just
> forwarding a cached RA? 

We also have difficulty understanding this. But our guess is that 
the processing inside a box takes more time than we anticipated. 

> How much faster is it than the MN soliciting
> itself?

Main difference between MN soliciting and AP soliciting is that, 
with the latter, we can realize a scheme (similar to Hash based 
FastRA) in a simpler way. 

We can assume that an AP knows all the ARs in a link. 
So AP can send UNICAST RS (to remove random delay) 
and solicit ARs in turns (for load balancing). 

When a new host is attached to the AP, 
AP can sends an unicast RS to a chosen AR 
1) with unspecified source address 
2) with the host's MAC address in TSLLAO. 

Upon receiving the unicast RS,  
the AR can send an RA immediately 
(because it is solicited in unicast).
in unicast (using TSLLAO)  

Also AP take turns to solicit ARs, 
such as this time AR1 next time AR2 
to achieve load balancing. 

Hence no load balancing mechanism is needed 
in ARs. 

> Surely the same logic is needed for the AP or there would be collisions
> if there are multiple routers on the link.

Yes, AP needs some logic (but simpler one, in my opinion) and 
for hosts and routers, only TSLLAO is needed. 
Other than that there is nothing to change in them.  

How do you think of it? 

Best Regards

JinHyeock