8 Apr
2005
8 Apr
'05
7:08 p.m.
Hi Tina,
I enjoy reading your posts, thanks a lot for the great
work you are
doing for ser users!
Thanks :-)
I am going to consider that kind of scenario as well
(load balancer
returning Virtual IP address). I think for such configuration server
side has to keep session information and always forward a call to the
right server.
I believe the load balancer can be in front and transparantly translate addresses in the
SIP messages:
User agent always sees a.b.c.d
|
Load balancer with public IP a.b.c.d
| |
ser1 (10.0.0.2) ser2 (10.0.0.3)
Paul: You have a similar load-balancing solution, right? Do you use a commerical load
balancer that you can reveal the name of? :-)
The load balancer need to understand SIP (sort of) and use something (ex. IP address of
user agent) to select SER server to send to and rewrite incoming to 10.0.0.2 and 10.0.0.3
respectively and outgoing to a.b.c.d. ser1 and ser2 will happily believe they are alone
and communicate directly with user agent using their own private addresses. Both should
know about all users (usrloc). Paul just recently posted a small patch for a setup where
they use two-way replication between two mysql servers and where each SER instance will
save all REGISTERs it receives from user agents, but only save to memory those replicated
from the other SER peer. Klaus pointed out that the same can be done by not doing mysql
replication, but have one DB for each SER and just use t_replicate() and save_noreply()
(for two servers, for more than two you need to use forward_tcp()).
I have heard complaints that this approach will generate too much network traffic. Also,
t_replicate() does not guarantee delivery of the replication (forward_tcp is better, but
not fool proof). So, the "best" solution would probably be to hope that
Paul's recent TCP/UDP patch for network access to FIFO commands get included in the
CVS. Then, a new replication module should use XMLRPC or whatever protocol the patch is
using to forward (in a guaranteed mode) the usrloc information, which then would be
injected directly into SER's memory, just like save() would, and of course in whatever
db_mode you would like. The replicaton module would have to keep a queue (of course,
flushed to a DB or something) in case of network problems, so that the replication would
be done (sooner or later) regardless of problems.
Of course, this is a major undertaking, so for most replication scenarioes, I would
think the forward_tcp() + save_noreply() would work just fine.
g-)
"Greger V. Teigre" <greger(a)teigre.com>
wrote:
I was thinking about a load balancing scenario where the load
balancer will replace the IP addresses.
g-)
---- Original Message ----
From: Tina
To: Greger V. Teigre
Sent: Wednesday, April 06, 2005 09:45 PM
Subject: Re: [Serusers] still no help - usrloc synchronization
Thank you for givingme the scenario with
"restricted IP" NAT, I am
starting to find some acceptable solution.
Unfortunately, "one-public-IP" approach is not free from problems
also. If your SIP router inserts this "one-public-IP" into the VIA
header, the reply routing goes via wrong SIP server...
If your SIP server inserts its real-IP-address - the scenario
mentioned above is still not resolved.
Any comments?
Tina
"Greger V. Teigre" <greger(a)teigre.com> wrote:
See inline.
Yahoo! Messenger
Show us what our next emoticon should look like. Join the fun. 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 t! he 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(a)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:
Do you Yahoo!?
Better first dates. More second dates. Yahoo! Personals 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(a)yahoo.com
! ; Cc: serusers(a)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(a)yahoo.com
> Cc: serusers(a)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(a)lists.iptel.org
>>> http://lists.iptel.org/mailman/listinfo/serusers
>>>
>>>
>>>
>>
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