Re: [rtcweb] NAT behavior heuristics

"Tirumaleswar Reddy (tireddy)" <tireddy@cisco.com> Sun, 05 August 2012 21:49 UTC

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From: "Tirumaleswar Reddy (tireddy)" <tireddy@cisco.com>
To: Randell Jesup <randell-ietf@jesup.org>, "rtcweb@ietf.org" <rtcweb@ietf.org>
Thread-Topic: [rtcweb] NAT behavior heuristics
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Date: Sun, 5 Aug 2012 21:49:49 +0000
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Subject: Re: [rtcweb] NAT behavior heuristics
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> And that's a rub, since in many/most cases, the 3G/LTE people will
> likely be talking to non-3G/LTE people, and if either side needs
> keepalives, then radio will be kept active.  Note we're talking
> long-term inactive media flows and an inactive (or rarely active)
> datachannel, such as a client using PeerConnection and DataChannels to
> keep a registration or empty conference alive, or various non-phone-
> like applications.

If just 3G/LTE supports PCP and non-3G/LTE does not support PCP -> Any STUN indications coming from the non-3G can be dropped by the Mobile Network itself to avoid reaching the Mobile Node, since it knows NAT binding is alive using PCP. 

--Tiru.

> -----Original Message-----
> From: rtcweb-bounces@ietf.org [mailto:rtcweb-bounces@ietf.org] On
> Behalf Of Randell Jesup
> Sent: Sunday, August 05, 2012 1:18 AM
> To: rtcweb@ietf.org
> Subject: Re: [rtcweb] NAT behavior heuristics
> 
> On 8/2/2012 7:15 PM, Dan Wing wrote:
> >> -----Original Message-----
> >> From: Martin Thomson [mailto:martin.thomson@gmail.com]
> >> Sent: Thursday, August 02, 2012 4:02 PM
> >> To: Dan Wing
> >> Cc: rtcweb@ietf.org
> >> Subject: Re: [rtcweb] NAT behavior heuristics
> >>
> >> I assume that this applies only to the NAT that doesn't exist yet
> and
> >> that we will have to live with status quo (and the current keep-
> alive
> >> recommendations) until PCP becomes bountiful.
> >
> > Yes.  PCP is new, somewhat like RTCWEB.
> >
> > There is an incentive for the existing CGNs, deployed by almost all
> > 3G/LTE carriers around the world, to have their vendors add PCP
> > support to those NATs, as it saves battery lifetime for their
> > subscribers and reduces chatter on their network.  Incentives are
> > well aligned for that to happen.
> >
> > I agree that home NATs, enterprise NATs, and enterprise firewalls
> > do not have those same incentives.
> 
> And that's a rub, since in many/most cases, the 3G/LTE people will
> likely be talking to non-3G/LTE people, and if either side needs
> keepalives, then radio will be kept active.  Note we're talking
> long-term inactive media flows and an inactive (or rarely active)
> datachannel, such as a client using PeerConnection and DataChannels to
> keep a registration or empty conference alive, or various non-phone-
> like
> applications.
> 
> An alternative mechanism for keepalives might help - you can use
> short-TTL packets to prop the local router without letting the packet
> go
> all the way to the other end.  If the fixed-station PC uses this TTL
> trick, and the mobile unit uses PCP, the mobile unit can keep its radio
> off.
> 
> Short-TTL can be handy for reducing loads on servers, especially where
> the port needs to stay open with no real traffic for long periods
> (think
> SIP).
> 
> The local router is rarely more than 5-7 hops from a device, though
> there are pathological cases; this could be configured (and
> disableable).  There are also ways to do discovery on the local router;
> these might work better than discovery of UDP port binding time, which
> is known to not work.
> 
> 
> --
> Randell Jesup
> randell-ietf@jesup.org
> _______________________________________________
> rtcweb mailing list
> rtcweb@ietf.org
> https://www.ietf.org/mailman/listinfo/rtcweb