Re: draft-bagnulo-pshim6-01.txt

[Deguang Le <[e-mail]>]

marcelo bagnulo braun schrieb:

> Hi Deguang,
> 
> El 13/05/2007, a las 17:37, Deguang Le escribió:
> 
>> Dear Prof. Marcelo,
>> page5:
>>  When H1 sends the first packet addressed to the CMULA of H2, the
>>    packet is intercepted and processed by the P- Shim6 box of the
>>    multihomed site.
>>
>> As above description, H1 sends the first packet, which uses the CMULA 
>> of H2 as the destination address. The CMULA is site-local adddress.
>>
> 
> right
> 
>> Since the destination addresss of the first packet is the CMULA of H2 
>> that belongs to H2's site, I wonder if this packet can be routed in 
>> H1's site.
>>
> 
> this packet is routed to the P-shim box in the H1 site. the P-Shim6 box 
> of the H1 site will then establish the shim6 context whcih will have the 
> CMULAs as ULIDs and regular PA addresses as locators. After that it will 
> forward the packets outside H1 site towards H2 site containing the PA 
> addresses as locators.
> 
> So the packets will carry PA addresses in the IPv6 header once they 
> leave the site. CMULAs are only routed inside the local site, so this 
> would be compliant with proposed usage of ULAs.
> 
> does this address your point?
Thank you very much for your detailed explaination. :-)
As you said, through the path from H1 to P-shim, the destination address 
of this packet is the CMULA of H2, which however is not routable in the 
H1's site (the reasions have been listed below). Normally, the CMULA of 
H2 can only be routable in the H2's site since it belongs to site-local 
address. right?
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
>>
>