To bad not every UA supports _SRV lookups, so round robin is not exactly
what I'm looking for.
NAT Traversal is a bit of a problem with multiple IP addresses, however, if
you use direct routing (and have all the boxes in the cluster reply from the
same IP) there shouldn't be a problem.
Spreading the contacts can be done with t_replicate (and flushing the
database often enough) so that if a ser hosts goes down the contacts are
already in the database, which is loaded at a restart.
This could actually work I think, I may have a test environment available
today so I might test this :)
Kind regards,
E. Versaevel
-----Oorspronkelijk bericht-----
Van: Klaus Darilion [mailto:klaus.mailinglists@pernau.at]
Verzonden: woensdag 1 december 2004 21:32
Aan: E. Versaevel
CC: serusers(a)lists.iptel.org
Onderwerp: Re: [Serusers] Loadbalancing / high availability
Hi Erik!
Another easy way for loadblancing ist the usage of SRV records for the
SIP domain.
And there are a lot of other problems:
- caching of the contacts of the registered clients (use t_replicate)
- NAT traversal: doesn't work that easy with multiple proxies with
multiple IP addresses.
- ...
search in the mailinglist archive - there are already several threads on
this topic.
regards,
klaus
E. Versaevel wrote:
Hello,
I was wondering if it is necessary for a SIP packet from a specific call
to
always go through the same server?
For instance, if you have a load balancer distributing requests over a few
servers, it is possible that an INVITE ends up on 1 server while the
following INVITE with the credentials ends up on another, would this be a
problem (ie, break the authorization) or should you use a SIP aware
loadbalancer for this (who looks at the callid for example)?
Assuming the ser servers are setup to use the same userdatabase (and
t_replicate to eachother) the picture would be something like this:
|
--------------
|loadbalancer|
--------------
|
|
--------------------
| | |
------- ------- -------
| | | | | |
| ser1| | ser2| | ser3|
| | | | | |
------- ------- -------
If you setup the servers with the same IP as the load balancer and stop
them
from replying to ARP requests for that IP, replying
back thru a NAT should
not be a problem.
Just thinking out loud, I could use SER for the load balancing and t_relay
the packets, however that would require some tampering with the VIA
records
(and I should use a reply to via in that case to the
original IP the SIP
request came from, eg not the load balancer) this way outgoing SIP traffic
would not have to go thru the ser loadbalancer again to get out, hmm, it
might even be possible to use a route-record header to get the packets
back
at the correct server...
Kind regards,
E. Versaevel
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