Hi Pekka,

I have some precisions on HIP inlined below,

[...]

> 5. Deployment Considerations

>     SHIM6 and HIP both require support in both ends before their
>     benefits can be realized.
>
> ==> I think you should go a bit deeper on this.  Important question
> to ask should be, "What impact does enabling this mechanism at one
> end have, when it isn't supported on the other?"  For example, in
> HIP there are extra DNS requests for new RR with HIP, with fallback
> to A/AAAA (i.e., extra delay of at least 1 DNS roundtrip, possibly
> more when trying to connect to any non-HIP destination).

I don't think that is necessarily the case. The HIP DNS draft has no 
normative text describing that lookups should be serialized and 
ordered. It is entirely possible that you issue simultaneously A/AAAA 
and HIP RR QUERIES (and I was told my DNSext people that it's not a 
problem.) If you receive a HIP RR the other end does support HIP and 
you establish an association, and if no HIP RR comes back you connect 
with plain IP.

[...]

>     HIP depends on the IPsec [IPSEC] protocol for basic operation. 
> It also depends on the existence of a HIP Rendezvous Server for its
> mobility mechanisms.
>
> ==> you might also mention how the HIP rendezvous server is
> discovered (I personally don't know, but I suspect there may be an
> issue there..)

A MN's rendezvous server information would typically be stored in the 
DNS using the HIP RR. This is similar to storing MIPv6 HA IP address 
in the DNS. 

>     SHIM6 also uses a return routability test, plus at least a
>     verification that the new locator is a locator of the same node
> (but does not verify that the control message was actually sent by
> that node) using a technique known as Hash-Based Addresses; it also
> optionally allows CGAs for more security.
>
> ==> it might be worth saying here that the verification requires
> basically a RR test (to make sure that the IP address is valid)
> until the address is taken to use.
>
>     HIP, on the other hand, requires strong cryptographic checks on
> all control messages.
>
> ==> but does strong crypto (as such) prevent 3rd party bombing and
> other attacks? You'll just know (unless you use something like
> opportunistic ipsec or BTNS) who did it..

HIP also has address reachability checks which prevents 3rd party 
bombings.

> 6.2. Data security
>
>     HIP requires that IPsec [IPSEC] be used for data, whereas IPsec
> is optional for MIP6 and SHIM6.
>
> ==> at least at some point using ESP NULL encryption was OK in the
> HIP context so while data security support is required, its use is
> not mandated.

HIP as mandatory support for ESP NULL encryption with HMAC-SHA1 
integrity.

Best,

--julien

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