Re: draft-bagnulo-pshim6-01.txt

marcelo bagnulo braun <marcelo@it.uc3m.es> Tue, 15 May 2007 14:19 UTC

Envelope-to: shim6-data@psg.com
Delivery-date: Tue, 15 May 2007 14:20:40 +0000
Mime-Version: 1.0 (Apple Message framework v624)
Content-Type: text/plain; charset="ISO-8859-1"; format="flowed"
Message-Id: <198c2e678e62f81282064f84cc4c2a09@it.uc3m.es>
Content-Transfer-Encoding: quoted-printable
Cc: shim6@psg.com
From: marcelo bagnulo braun <marcelo@it.uc3m.es>
Subject: Re: draft-bagnulo-pshim6-01.txt
Date: Tue, 15 May 2007 16:19:22 +0200
To: Deguang Le <le@cs.uni-goettingen.de>

El 15/05/2007, a las 10:21, Deguang Le escribió:

>
> Thank you very much for your explanation.
> As you said, the p-shim box has to perform the router function and 
> advertise the route through some routing protocol (e.g. IGP) each time 
> when a node in the site wants to establish communication with external 
> nodes. Right? :-)
>

not each time.
the P-shim box will announce a route towards the generic CMULA prefix 
so it will sink all packets containing a CMULA destiantion address. If 
you have internal CMULAs prefixes, these will be mroe specific than the 
generic CMULA prefix, so, packets with the local CMULA prefix will be 
routed with this more specific routes (rahter than being sink towards 
the P-shim6 box)

> If this is true, I wonder if this mechanism is efficient because I 
> think it needs take considerable time to update the routes in the site 
> (especially when the site is large including many routers) each time 
> before the node can establish communication with external nodes.
>

i don't think this is the case, see above...

makes sense?

regards, marcelo


> What do you think?
>
> Cheers,
> Deguang
>
>
>
>
>
>
>> Regards, marcelo
>>> With Best Regards,
>>> Deguang
>>>
>>>
>>>> then P-shim6 box would replace the CMULA to a globally routable PA 
>>>> address. So the CMULAs would be  routed inside the sites and PA 
>>>> address will be routed in the interdomain
>>>> that makes sense?
>>>> Regards, marcelo
>>>>
>>>>> Therefore, I only wonder how this packet could be routed from H1 
>>>>> to P-shim box correctly.
>>>>>
>>>>> With best regards,
>>>>> Deguang
>>>>>
>>>>>
>>>>>
>>>>>> Regards, marcelo
>>>>>>
>>>>>>> The reasions are ss follows:
>>>>>>> According to rfc2373, routers must not forward any packets with 
>>>>>>> site-local source or destination addresses outside of the site.
>>>>>>>
>>>>>>> Reference [12] has the following description:
>>>>>>> Unique Local IPv6 Unicast Addresses are intended for local 
>>>>>>> communications, usually inside of a site.
>>>>>>>
>>>>>>> RFC4193 provides operational guidelines that forbid default 
>>>>>>> routing of local addresses between sites in section 4.1.
>>>>>>>
>>>>>>> By the way, the reference [12] seems have been updated by RFC 
>>>>>>> 4193.
>>>>>>>    [12]  Hinden, R. and B. Haberman, "Centrally Assigned Unique 
>>>>>>> Local
>>>>>>>          IPv6 Unicast Addresses", draft-ietf-ipv6-ula-central-01 
>>>>>>> (work
>>>>>>>          in progress), February 2005.
>>>>>>>
>>>>>>> Cheers,
>>>>>>> Deguang
>>>>>>>
>>>>>
>>>
>
>