Re: [pcp] On the interaction between PCP sever and NAT (or multiple NATs)

["Dan Wing" <[e-mail]>]

> -----Original Message-----
> From: [e-mail] [mailto:[e-mail]] On Behalf Of
> ???
> Sent: Wednesday, October 13, 2010 8:37 PM
> To: pcp
> Subject: [pcp] On the interaction between PCP sever and NAT (or
> multiple NATs)
> 
> Hi,ALL
> 
> 	 In "draft-wing-softwire-port-control-protocol-02" the Fig.2
> shows that the NAT devices can work with separate PCP Server. But I
> only find the detailed specification between the PCP server and
> clients. The interation between PCP server and NAT is obscure and the
> suggested xml-style communication is not clear. How dose it works?
> Based on TCP,UDP or other mature transmission technology? what
> information should it contain ?

Undefined.  The PCP server and NAT could be implemented in the same
device (which I expect will be common), and share whatever 
data structures are necessary between them using whatever they
find natural (perhaps a socket-based API, perhaps shared memory,
etc.).  If PCP server and NAT are implemented in separate devices,
it would be a proprietary protocol between the PCP server and
the NAT(s).

> Below is some question and considerations on the interation between PCP
> sever and NAT. Comments and suggestions are welcome and appreciated.
> 
> 1.Is the interation between PCP server and NAT private or public ?  In
> another word,is it possible that PCP server and NAT are producted by
> differnt network equipment vendors. IF we expect two devices from
> different vendors can work together without trouble, the specification
> of the interation is necessary.

It's a private interface.

-d

> 2. In the PCP draft, NAT device only receives address binding
> information from PCP server. Is there any message that NAT should tell
> PCP server? Intuitively, PCP server should detect the failure of NAT
> device, expecially in multiple NATs scenario. Tranditional  echo or
> 'hello' protocol is available. on the purpose redundancy and load-
> balancing the NAT group id and the current load is expected to be known
> by PCP server. (plz see 3)
>
> 3. Can a single PCP server interact with multiple NATs? Because the
> reliability is very important for CGN devices, mulitple NATs is highly
> desireable for both load balacing and redundancy. If the multiple NAT
> scenario makes sense in PCP context, the specification of the
> interation should be more carefully designed.
> plz see http://tools.ietf.org/html/draft-xu-behave-stateful-nat-
> standby-04 and http://tools.ietf.org/html/draft-wang-behave-nat64-load-
> balancer-02 for more information
>
> 4.TCP or UDP? I'm not sure about that part. If reliable connection is
> need between PCP server and NAT ,TCP is prefered.
>
> 
> 
> 
> 
> 
> Best regards.   2010-10-14
> 
> ********************************************************
> *    Linjian Song ,Ph.D candidate                      *
> *    Department of Computer Science & Technology       *
> *    Tsinghua University, Beijing, P.R.China(100084)   *
> *    Tel: [phone]-6864                         *
> *    Email: [e-mail]      *
> ********************************************************
> 
> 
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