See inline.

> If you use DNS server for load balancing... the client receives one
> of your domain IP addresses according to SRV. I don't see the problem
> with a call here, cause UAC asks the address only once (before
> sending INVITE). UAC already has the IP for BYE/reINVITEs. So why
> would you replicate INVITEs?    

I would never replicate INVITEs, I would just make sure that they are proxied through the correct SER server (i.e. IP).

 

The problems depends on your setup. If you have SERs with different IPs, ex UA1 has registered with server  A and UA2 has registered with server B: If UA2 wants to call UA1 and UA is behind an IP restricted NAT, server A is stored in the NAT table of the NAT in front of UA1.  If server B sends an INVITE to UA1, the INVITE will be refused by UA1's NAT.

    This is why a "one public IP" in front of a load balancing cluster probably is a good way to go.

> If you use IPVS/LVS... I believe you can force SER to insert it's
> public IP into VIA, so there is no problem with replies. With regard
> to another requests, I believe load balancer keeps connection
> template, then when another request comes it would be forwarded to
> the same ser.   

Yes. There are different "keys" to use to load balance SIP messages.  One good way from a NAT point of view is to use originating IP address.  What you must remember is that the problem is not on the server side, but on the client side.  The NAT will in many situations stop incoming UDP packets if the originating ip:port is not already stored in the NAT table.  The Via header does not matter for the NAT.

g-)

> Any comments?
>
> "Greger V. Teigre" <greger@teigre.com> wrote:
> Yes, I believe that is so. But still you get a problem if the NAT is
> restricted, port-restricted or symmetric... The best would be to load
> balance and always make sure that a given client is handled through a
> given
> SER (REGISTER and INVITEs). That includes forwarding INVITEs from one
> SER to
> another... OR you must load balance in front of your servers with one
> common
> public IP.
> g-)
>
> Matt Schulte wrote:
>> Ack, I didn't even think about NAT. Would these be added before it
>> gets sent off to the second proxy? ie:
>>
>> if (!src_ip==blah.netlogic.net) {
>> add_rcv_param();
>> t_replicate("blah.netlogic.net", "999");
>> };
>>
>> -----Original Message-----
>> From: Greger V. Teigre [mailto:greger@teigre.com]
>> Sent: Tuesday, April 05, 2005 7:49 AM
>> To: Matt Schulte; kramarv@yahoo.com
>> ! ; Cc: serusers@lists.iptel.org
>> Subject: Re: [Serusers] still no help - usrloc synchronization
>>
>>
>> Well, you still have the NAT issues unless you do load balancing and
>> your
>> SER servers have the same public IP.
>> Have you looked at 0.9.0 nathelper function add_rcv_param() ? It will
>> add received info to the contact header for the other SER to
>> process. Haven't really tried yet...
>> g-)
>>
>> Matt Schulte wrote:
>>> I'm starting to lean this direction, using t_replicate and all. I
>>> could never get usrloc (db mode) to function properly.. t_replicate
>>> is
>>
>>> a dirty but very effective workaround.
>>>
>>> -----Original Message-----
>>> From: Greger V. Teigre [mailto:greger@teigre.com]
>>> Sent: Saturday, April 02, 2005 1:33 AM
>>> To: kramarv@yahoo.com
>>> Cc: serusers@lists.iptel.org
>>> Subject: Re: [Serusers] still ! no help - usrloc synchronization
>>>
>>>
>>> Have a look at this thread:
>>> http://lists.iptel.org/pipermail/serusers/2005-January/014669.html
>>> g-)
>>>
>>> Java Rockx wrote:
>>>> Tina,
>>>>
>>>> I thought I saw you post the other day that you did not want to use
>>>> t_replicate(), however, this is probably your best bet to getting
>>>> this
>>>
>>>> to work, IMHO.
>>>>
>>>> Regards,
>>>> Paul
>>>>
>>>> On Apr 1, 2005 4:08 PM, Tina wrote:
>>>>>
>>>>> Hi, please help me, I'm stuck with it!!!!!
>>>>> I am trying to set up several sers with a shared MySQL database
>>>>> for location service.
>>>>>
>>>>> I set in each ser.cfg:
>>>>>
>>>>> modparam("usrloc", "db_mode", 2)
>>>>> modparam("usrloc",
>>>>> "db_url","sql://ser:heslo@192.168.25.163/ser")
>>>>>
>>>>> and the servers are not synchronized.
>>>>> The I set
>>>>> modparam("usrloc", "db_mode", 2)
>>>>>
>>>>>
>>>>> made UAC (Xlite) register to one of the servers.
>>>>> I see it via usrloc, but there is no record in "location" mySQL
>>>>> table....So others do not see the client and I'm unable to make
>>>>> calls....
>>>>>
>>>>>
>>>>> Please help how to work with usrloc and mySQL...
>>>>>
>>>>> Tina,
>>>>> software engineer
>>>>>
>>>>> ________________________________
>>>>> Do you Yahoo!?
>>>>> Better first dates. More second dates. Yahoo! Personals
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> Serusers mailing list
>>>>> serusers@lists.iptel.org http://lists.iptel.org/mailman/listinfo/serusers
>>>>>
>>>>>
>>>>>
>>>>
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>>>
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