On 3/9/14, 8:07 PM, Alia Atlas wrote:
Joel,
On Sun, Mar 9, 2014 at 7:45 PM, Joel M. Halpern <jmh(_at_)joelhalpern(_dot_)com
<mailto:jmh(_at_)joelhalpern(_dot_)com>> wrote:
...
While there are encapsulations whose primary purpose is adding
additional information, most of the cases I can think of (MPLS,
LISP, GRE, Mobile-IP) are cases where the primary purpose of the
encapsualtion is to direct the traffic over a path that it might not
otherwise chose or otherwise be able to traverse.
For MPLS, I think that the services, such as L3VPN, VPLS, pseudo-wires,
etc are hiding data from the underlay and conveying extra info.
Arguably, so is LISP.
If you consider "frame format" extra information, then I guess
Pseudowires carry extra information. But the primary point is to get
the packet across the net.
At that point, you end up calling the tunnel endpoint identifier
metadata instead of delivery information. Which seems to reduce the
value of the distinction.
In the case of LISP, as specified, I don;t see that it carries extra
packet information. It carries some tunnel maintenance information.
When we add the LCAF in the resolution, we can get an implicit packet
type. But even then the primary purpose of the encapsulation is to get
the packet to the right place on the net. That is why it separates
location (the outer destination) from identity (the inner destination).
Yours,
Joel
Regards,
Alia
Yours,
Joel