[Pana] Re: Sam's IESG comments

[Mark Townsley <townsley at cisco.com>]

Alper Yegin wrote:
> The framework document says that sometimes a PAC is expected to
> reconfigure its address after PANA.  The PANA protocol has no
> normative discussion of this.  In order to get interoperable
> implementations, you need to clearly indicate when address
> configuration is required.  Perhaps you are deferring this to future
> documents.  If so, then the framework should indicate that unless a
> PAC implements a protocol extension that mandates address
> reconfiguration and that protocol extension is used, then the PAC need
> not do address configuration.  Or, if address reconfig is supported in
> the base protocol, you need to have normative language describing it.
>
> -> We had thought about it and even designed an AVP to tell PaC what
> mechanism to use for re-configuration. Version 12 of the spec included not
> only an indication that the PaC shall reconfigure a new IP address but also
> the name of the mechanism to use (DHCPv4, DHCPv6, stateless addr. autconf,
> IKEv2, etc.).
>
> -> Then we realized we were stepping outside the scope of the access
> authentication, and we decided to remove it. We decided that anything with
> IP address configuration is outside the scope. 
>
> -> Would you suggest we re-introduce what we had but only with a one-bit
> info that says "PaC shall configure a new IP address" (without enumerating
> any specific address config mechanisms)?
>   
Sam, the notification of an IP address change in the PANA protocol 
itself was among the items that we removed in order to reduce PANA's 
complexity. If the IP address changes for some reason, whether it is 
configured via DHCP, SA, IKE, IPCP, or manually, PANA would need to 
react like any other protocol that would be affected (e.g., TCP) by 
this. I believe we discussed that ending the current session and 
restarting PANA would be a perfectly reasonable thing to do, but not 
certain that this made it into the text.

You suggest that PANA try and indicate when address configuration is 
required. Trying to enumerate this is due to the number of environments 
PANA wishes to applicable in and the number of ways an address may be 
configured sends the author and the reader out into the weeds rather 
quickly. Rather, I believe in the base framework and protocol spec it is 
sufficient to say that the IP address may change, and if it does PANA 
needs to know this and may need to restart. Specific "PANA with Foo" 
specifications may make this recommendation more precise if need be.

- Mark

_______________________________________________
Pana mailing list
Pana at ietf.org
https://www1.ietf.org/mailman/listinfo/pana