Subject: [lisp] Issue Title (number): PIvsPA (87)

From: Darrel Lewis <[email-masked]>
Date: Tue, 20 Jul 2010 14:20:08 -0700

Issue Title (number): PIvsPA (87)
Draft Section: 3
Issue Description:  Existing vs New Addressing 
Comments:

Section 3

    A globally routed address block (whether PI or PA) is not
    an EID-prefix. However, a globally routed address block may be
    removed from global routing and reused as an EID-prefix. A site
    that receives an explicitly allocated EID-prefix may not use that
    EID-prefix as a globally routed prefix assigned to RLOCs.

The above implies that if an existing site has IPv4 addresses that are used for global connectivity, and thus act as RLOCs, the site can not use these addresses as EIDs, unless the site removes them from global routing, and thus stops using them as RLOCs.

Does the spec assume that IPv4 sites that want to use LISP would need to get another block of IPv4 addresses for the EID prefix ?

If yes, then where would these IPv4 addresses come from ?

If a site that has IPv4 addresses and uses them for global connectivity (these addresses act as RLOCs) wants to transition to LISP, but can not get another block of IPv4 address for the EID-prefix, then how would that site transition to LISP, and what are the implications on that site's connectivity during the transition? E.g., could some,
but not all, of the border routers of the site during the transition be xTRs ? If yes, then how would an ITR attract traffic from a site if the site also has a default route to a non-ITR router ?

Does the EID space need to be aggregatable, as if yes, then how would one accomplish this in the context of IPv4 addresses ?

Response:

Dear Yakov-

Thank you for your contribution to draft-ietf-lisp-06.txt. The draft authors
have reviewed your comments but are cannot determine whether changes should
be made to the document. Its probable that further discussions on the topics 
above would contribute to a usage or deployment draft.  Please bring this 
issue to the LISP working group mailing list, [email-masked], for further 
discussion. Should the WG reach consensus that changes are required, the 
authors will incorporate appropriate text into a future version of the draft.

	Thanks!
	Darrel, for the LISP document authors