< Previous by Date Date Index Next by Date >
< Previous in Thread Thread Index Next in Thread >

Re: [reSIProcate] SRV behavior


On Thu, 2006-02-16 at 11:36 -0800, Matt Porter wrote:
> i created SRV records with the same weight and priority, in an attempt
> to load balance calls.
> both records happen to be pointing the same machine, on different
> ports.
>  
> The INVITE will use 1 record, and then the BYE on the other.  which
> obviously causes problems.
>  
> Shouldnt the entire dialog from INVITE to BYE use 1 record, instead of
> using a record per transaction?
> Is this a bug, or am i misunderstanding how the SRV's are supposed to
> work.

You want to get that effect, but that is not the correct way to do it,
as it requires the proxy to maintain state to know which SRV record to
use for which dialog.

First, the only hosts that matter are those that Record-Route themselves
during the INVITE transaction.  The ones that don't Record-Route are not
on the path of the BYE.

The ones that do Record-Route themselves should not record themselves
using their normal names, but rather using IP addresses.  Or better,
they should use domain names that have SRVs that preferentially resolve
to the address of the proxy itself, and secondarily to the proxy's load-
balancing twin.

Once that is done, the BYE will go through the same proxy the INVITE
happened to go through, unless that proxy failed, in which case, it will
go through the twin.

Dale