On Tue, 2008-12-09 at 19:59 +0530, VG wrote: > Hi, > > I come to know about the feature HA maintained in sipx by DNS SRV > records. > > It means SIPX communicate with DNS Sever each time. like sending of > health packets or other things comes in picture. > I do not have any exp. in DNS Srv system, so it can be a foolish > question. > But how could i come to know that : > How DNS server comes to know that Master Server is Down or Client serve is > Down.
It doesn't. When something (whether a user agent or some other SIP system) wants to send to a domain, it queries the DNS to find out how to reach that domain. The NAPTR/SRV records tell it how to do that (see RFC 3263). The records we generate for sipXecs HA tell it to try the proxy systems, choosing one at random (equally weighted), and using the others as fallbacks. It is the senders responsibility to do the correct DNS lookups and to fall back if the chosen system does not respond. No one component is responsible for the fact that the distributed system provides high availability - it's just the emergent behavior of the configuration and every participant following the rules. _______________________________________________ sipx-dev mailing list [email protected] List Archive: http://list.sipfoundry.org/archive/sipx-dev Unsubscribe: http://list.sipfoundry.org/mailman/listinfo/sipx-dev
