[Serusers] NAT ping and consumer router

[Richard]

Hi,

Sending an empty SIP packet is probably the lightest-load method for ser and
UA. The only requirement to make it work is NAT devices refreshing binding
on inbound traffic.

Thanks,
Richard


-----Original Message-----
From: serusers-bounces at iptel.org [mailto:serusers-bounces at lists.iptel.org] On
Behalf Of Vitaly Nikolaev
Sent: Monday, August 23, 2004 7:05 AM
To: John Todd; Jiri Kuthan
Cc: serusers at lists.iptel.org
Subject: RE: [Serusers] NAT ping and consumer router

Hi,

I do not pretend that this is the best way, but I use sipsak and
location database and send every minute message to all registered
contacts. 

I do not really want to make SER do this stuff because it is a bit out
of scope of SIP PROXY server...


> -----Original Message-----
> From: serusers-bounces at iptel.org [mailto:serusers-bounces at lists.iptel.org]
On
> Behalf Of John Todd
> Sent: Monday, August 23, 2004 10:30 AM
> To: Jiri Kuthan
> Cc: serusers at lists.iptel.org
> Subject: RE: [Serusers] NAT ping and consumer router
> 
> 
> The problem, as I see it from this discussion, is that some devices
> do not work correctly with the simple UDP packet sent to port 5060 of
> the remote UA, because there is no reply packet which is what keeps
> the NAT mapping of some NAT router/translators.  I don't see this as
> a UA problem; if there is no NAT translation, then even the
> best-programmed UA can't receive an inbound INVITE.
> 
> The manner in which Asterisk handles this type of keepalive is
> somewhat simple but novel, and may be worth examination.   Every X
> seconds, an OPTIONS request is made to the remote UA by the server.
> Even if the UA does not support the OPTIONS query, it typically hands
> back a SIP error, which serves the purpose of keeping the NAT
> translations open.  If the device supports OPTIONS, then a "normal"
> SIP reply is sent, also serving the intended purpose.
> 
> Perhaps instead of a UDP packet with no content, a SIP OPTIONS
> request could be sent by SER.  This could perhaps be an selective
> flag associated with the NAT support in SER, so that either the dummy
> packet or the OPTIONS packet could be transmitted by the module.
> 
> There are other solutions here, like reducing the interval of
> REGISTER requests to serve the same purpose of refreshing NAT table
> mappings.  However, one could argue that this method has a much
> higher load than an OPTIONS packet, especially when scaling across
> thousands or tens of thousands of clients in an environment where
> external databases (i.e. Radius, SQL, etc) are used for
> authentication lookups.
> 
> Note that there have been numerous examples of such poorly-written
> SIP stacks on UA devices that they would crash on an OPTIONS request.
> Their repair is outside the scope of SER or this discussion.
> 
> JT
> 
> 
> At 2:56 AM +0200 on 8/23/04, Jiri Kuthan wrote:
> >I beg to disagree -- we should not create to much workarounds around
> >imperfect clients. In particular, incomplete NAT traversal support
> >is a serious shortcoming in a UA and I would discourage people from
> >using such devices.
> >
> >Other front to attack would be NATs -- there is an effort in IETF
> >focusing on that, but that's obviously an activity which has no
> >impact on currently installed base.
> >
> >-jiri
> >
> >At 01:57 AM 8/23/2004, Richard wrote:
> >>Hi Jesus,
> >>
> >>Changing UA is not always a viable solution due to pricing and other
> >>technical issues. Every UA has something broken in its
implementation
> and it
> >>would be very costly to change it because one thing (in this case,
NAT)
> is
> >>broken.
> >>
> >>Thanks,
> >>Richard
> >>
> >>
> >>-----Original Message-----
> >>From: Jesus Rodriguez [mailto:jesusr at voztele.com]
> >>Sent: Sunday, August 22, 2004 8:59 AM
> >>To: Richard
> >>Cc: serusers at lists.iptel.org
> >>Subject: Re: [Serusers] NAT ping and consumer router
> >>
> >>
> >>Use an UA that supports it (Sipura or Cisco for example).
> >>
> >>Saludos
> >>JesusR.
> >  >
> >>-------------------------------
> >>Jesus Rodriguez
> >>VozTelecom Sistemas, S.L.
> >>jesusr at voztele.com
> >>http://www.voztele.com
> >>Tel. 902360305
> >  >-------------------------------
> >--
> >Jiri Kuthan            http://iptel.org/~jiri/
> 
> _______________________________________________
> Serusers mailing list
> serusers at lists.iptel.org
> http://lists.iptel.org/mailman/listinfo/serusers


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