Re: [pcp] WG Call for Adoption: draft-tsou-pcp-natcoord-09

> -----Original Message-----
> From: pcp-bounces@ietf.org [mailto:pcp-bounces@ietf.org] On Behalf Of
> Simon Perreault
> Sent: Monday, January 07, 2013 1:57 AM
> To: pcp@ietf.org
> Subject: Re: [pcp] WG Call for Adoption: draft-tsou-pcp-natcoord-09
> 
> Salut Alain,
> 
> Le 2013-01-03 17:39, Alain Durand a écrit :
> > 1) This functionality can be achieved very simply on a CPE by sending
> multiple PCP requests.
> >       This would remove the complexity of port set indexes, max port
> set, etc...
> 
> One reason for MAP_PORT_SET is scalability.
> 
> - On the PCP client: you don't want to deal with e.g. 2048 MAP requests,
> then 2048 refreshes every X hours, etc.
> 
> - On the NAT: it allows allocating one single "set" entry, which may
> very well occupy less state memory than 2048 individual map entries.
> 
> 
> Another reason is to get a contiguous chunk. There is no guarantee that
> multiple MAP requests will be able to obtain a contiguous chunk of port
> numbers. Some applications may find this property necessary (e.g. SIP
> clients).

By SIP, do you mean RTP?  If so, it seems draft-boucadair-pcp-rtp-rtcp 
provides that functionality.  draft-tsou-pcp-natcoord could, too, if
the size of the port-set is two ports, I guess?  Which should a client
or a server use?

-d

> > 2) There are already several DHCP (v4 and v6) options being defined to
> address this very problem,
> 
> No.
> 
> The DHCP options solve the very specific problem of provisioning a port
> set to a subscriber, in e.g. the LW4o6 use case.
> 
> MAP_PORT_SET is different. The best way to see it is as an extension to
> MAP: it allows to map port sets with PCP instead of single port numbers.
> It is applicable to LW4o6, but also in other use cases: applications
> that need chunks of continuous ports, Reinaldo's firewall use case, etc.
> 
> > 3) When asking for multiple of those port-sets, one may end-up with
> port sets on different
> >       external IP addresses.
> 
> The MAP opcode has the same concern, and the same answer applies. Let us
> know if you think it should be made clearer in the text.
> 
> > Also, when ports are running low, connections may be delayed until a
> new port set is acquired.
> 
> This is up to the PCP client to figure out. The same concern applies to
> the MAP opcode.
> 
> Simon
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