[radvd-devel-l] multiple RAs

Greg Daley greg.daley at eng.monash.edu.au
Sun Apr 3 20:57:18 EDT 2005


Pekka Savola wrote:
> On Sun, 3 Apr 2005, Bhupendra Gothwal wrote:
>>            i am having problem while working with the test bed for mobile
>> ipv6.
>>            in my case there are
>> 1) one mobile node (MN)
>> 2) two router (home router(R) and foreign router(AR))
>> 3) one home agent (HA)
>> i am in my home net but still i am receiving router advertisment from 
>> both
>> the router.thus my MN interface is assigning care of address(by auto
>> configuration) corresponding to both of the router.
>> that is even i am in the home net i am getting two care of address.
>> one bye my home router and other by foreign router.
>> can nebody tell me how to avoid addess autoconfiguration with the other
>> router and doing it only with home router.
> This doesn't seem to have anything to do with radvd, but..
> Maybe you should co-locate the Home Agent with Home Router -- so that 
> you would not get the router advertisement through the MN-HA tunnel when 
> you're at home?

I think Pekka is on the right track:
this is a deployment issue.

One router taking both functions HA and AR is likely to work well.

If you need to have two routers, the Home Agent doesn't necessarily
have to be an advertising router.  In fact, your home agent may be
set up so that it's impossible to visit the home network (try a dummy
interface as the home network)

Another option is to allow the Home Agent to be the only advertising
router on the Home link.

Neither of the above options will work particularly well if the Router
and the HA don't trust each other for route exchange.

A final option is to advertise exactly the same prefix as the router
(with a different router suffix) for the Home Network prefix.
The HA can proxy addresses out of the subnet easily, and may
advertise similar lifetime values to the other router. It may be
useful to lower the HA's advertised preference if it otherwise
isn't connected to the routing infrastructure though.


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