Subject: Re: [pcp] base #17 (closed): using PCP to reduce application-level keepalive traffic

From: "Dan Wing" <[email-masked]>
Date: Tue, 22 Feb 2011 16:08:04 -0800

> -----Original Message-----
> From: pcp issue tracker [mailto:[email-masked]]
> Sent: Tuesday, February 22, 2011 2:39 PM
> To: [email-masked]; [email-masked]
> Cc: [email-masked]
> Subject: Re: [pcp] base #17 (closed): using PCP to reduce application-
> level keepalive traffic
> 
> #17: using PCP to reduce application-level keepalive traffic
> 
> 
> Comment(by tena@…):
> 
> 
> 个人赞成，用PCP来减少应用keepalive流量的，但觉得NAT表项超时需要明确，用PCP消息
> 时，就不要用应用的keepalive
>  来刷新NAT表项的时间。
>  I support using PCP to reduce application-level keepalive traffic.
>  However, I think the NAT entries expiring out should be specified
> clearly,
>  if using PCP message, don't use application's keepalive to refresh NAT
>  entries time.

So, that would mean that once an application sends a PEER request to 
query the lifetime of the mapping, the application will forever have 
to re-send PEER requests to keep the mapping alive.

This seems counter-intuitive.  What is the advantage of requiring
the application to send occasional PEER requests, instead of allowing
it to just send its normal application traffic?

As an example, I don't see the purpose of requiring the application
to always send PEER messages if the Lifetime is 5 minutes and the 
application is normally sending traffic more frequently (e.g., a 
presence application routinely updates presence information of 
peers or of the client).  Sending the subsequent PEER messages is
extra load on the network (undesirable in general but especially
for wireless devices).

Of course, if the Lifetime is _less_ than the application's normal
traffic, the application could use PEER to extend the lifetime. 
But, in this case too, I would myself prefer the application be
allowed to send an application message which it might want to do
for other reasons, rather than being forced to send a PEER request.

Can you provide more details on why you are suggesting PEER
be re-sent forever?

-d