Re: [RAM] LISP NERD/CONS, eFIT-APT & Ivip compared

> If I was confused about some aspects of LISP-CONS then I figure
> other people may have been confused too.
>
> When I wrote my comparison, it was my impression that in
> LISP-CONS, as in LISP-NERD LISP 1 and LISP 1.5 (though the I-D
> says very little about 1.5) that the mapping data contains
> potentially multiple RLOC addresses, each with a Weight and
> Priority.  This is for the purpose of the ITR making its own
> decisions about which of the ETRs (one ETR is hopefully at each
> RLOC location) is currently reachable, including by receiving ICMP
> messages in response to encapsulated data packets which didn't
> make it to an ETR and probably also from messages sent by ETRs
> back to the ITR.
>
> So as part of my comparison I wrote (RW1):
>
>>> LISP-NERD/CONS:  As noted above, ITRs have complex functions,
>>> including making decisions on a packet-by-packet basis for MH
>>> service restoration, TE and I think load balancing functions.
>>> The ITR may or may not communicate with the ETR, but I think
>>> the ITR is always ready to accept ICMP messages as sign it is
>>> tunneling the data packets to the wrong address.
>
> to which you replied (DF1):
>
>> I beg to differ. The ITR simply does a cache lookup on the DA
>> when the DA has a routing table miss or a default route match.
>> When the cache lookup returns an RLOC it slaps a header on. It's
>> as simple as that.

I was talking about forwarding time. Once reachability is determined  
to a set of locators at control-time, they are programmed in hardware  
so the ITR forwarding time decision is to just use a preprogrammed  
encapsulation.

> So I looked closely at the LISP-CONS I-D, in particular at this
> paragraph in 6.4:
>
>   Priority, Weight, Unused, Loc-AFI, Locator:  See [LISP-01] for
>   details.  Oh, so it's just like a Blackberry.

These are the names of fields in the packet format description of the  
Map-Reply. In the CONS draft it is saying to refer to the LISP draft  
for details.

Dino

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