Hi, I want to know, if someone has tried to use clustering in asterisk to increase its scalability and make it distributed?? If yes, how easy it is to cluster? Can someone please ive me details about the same Thanks Varun __________________________________ Do you Yahoo!? New and Improved Yahoo! Mail - Send 10MB messages! http://promotions.yahoo.com/new_mail
Trilogy India wrote:>Hi, > >I want to know, if someone has tried to use clustering >in asterisk to increase its scalability and make it >distributed?? > >If yes, how easy it is to cluster? > >Can someone please ive me details about the same > >Thanks > >Varun > > >This has been discussed a number of times in the past, searching the archives will reveal the various technical reasons why a clustered SIP solution is very difficult to implement.. Your only real option for scalability is to distribute your users over many servers and interlink them with IAX and your dial plan.. For those who don't know how to search the archives.. Goto the bottom of the page at http://www.digium.com/index.php?menu=mailing_list and search.. Later..
Trilogy India wrote:> Hi, > > I want to know, if someone has tried to use clustering > in asterisk to increase its scalability and make it > distributed?? > > If yes, how easy it is to cluster? > > Can someone please ive me details about the sameAsterisk will not benefit from clustering. Jeremy McNamara
On Wed, 2004-08-04 at 09:30, Jeremy McNamara wrote:> Trilogy India wrote: > > > Hi, > > > > I want to know, if someone has tried to use clustering > > in asterisk to increase its scalability and make it > > distributed?? > > > > If yes, how easy it is to cluster? > > > > Can someone please ive me details about the same > > > Asterisk will not benefit from clustering.Not in the HPC sense, but it will in the high availability sense. -- Steven Critchfield <critch@basesys.com>
Jeremy McNamara wrote:> Trilogy India wrote: >> I want to know, if someone has tried >> to use clustering in asterisk to increase >> its scalability and make it distributed?? >> If yes, how easy it is to cluster? > >Asterisk will not benefit from clustering.It all depends on how one defines the term cluster. There was a time not so long ago when clusters had little or nothing to do with the kind of distributed parallel processing that is so often (perhaps wrongly) called clustering today. A more precise term would be grid computing, not clustering. DEC made the term cluster fashionable in the 80s with their VAXcluster architecture. They pretty much coined and owned the term back then. But those clusters where designed for high availability and redundancy, not for parallelising and distributing a compute job over multiple CPUs. Of course a VAXcluster would also increase scalability in the same way that mirrored web servers do, simply because they offer the same service on a single virtual network address. Connections to the service are then workload balanced between multiple nodes, but any given job is always executing entirely on a single node, unless the node goes down while the job is processing, in which case it is failed over to another node to continue there. In the hayday of the VAXcluster, if you used the word clustering for any bundling of computing resouces that did not meet the high standards set by VAXcluster technology, most IT folks would have lectured you like "That's not a cluster, it doesn't do proper failover, it doesn't have quorum, it doesn't have distributed locking" etc etc. Consequently, Unix vendors were extremely careful to avoid using the word cluster. They would use terms like workstation farm, compute farm, hot standby, etc etc. However, during the 90s the term cluster has become a catch all for anything that somehow bundles computing resources. In this sense, running multiple Asterisk servers to offer the same service on a domain name representing multipe IPs through round robin DNS or similar techniques is a form of clustering, much more so than grid computing is, at least in the original sense as it was defined by DEC. In the same sense, TDMoE is a form of clustering. Of course if your definition of clustering is grid computing, then your statement is correct. Grid computing does nothing for Asterisk. rgds benjk -- Sunrise Telephone Systems Ltd 9F Shibuya Daikyo Bldg., 1-13-5 Shibuya, Shibuya-ku, Tokyo, Japan __________________________________________________ GANBARE! NIPPON! Yahoo! JAPAN JOC OFFICIAL INTERNET PORTAL SITE http://mail.ganbare-nippon.yahoo.co.jp/
Clustering in its purest definition (HA, numa, parallel processing, etc) with asterisk is not really supported at the moment. However, you can do some things to increase the availability and scalability of phone services by using multiple pbx devices. I am by no means an expert in this area, but I am also interested in this area, so I'll meekly offer up my 2 cents. In terms of scalability, you could potentially have many asterisk 'nodes' that have their own pstn connections. Getting creative with the dial plans using the 'switch' command may achieve your scaling needs. There is some information on this in the wiki. http://www.voip-info.org/wiki-Asterisk+-+dual+servers In terms of HA/failover capabilities, you're pretty much concerned with the connectivity issues. Regarding the connectivity to the PSTN, failover mechanisms could be provided either through your PSTN carrier or through the use of a layer 1 switching devices. Most carriers provide, for a small charge, a failover capability across multiple PRI circuits. For instance, if you have a block of DID numbers pointed to a certain PRI, and that PRI were to go off-line for whatever reason, they would then send the calls directed to those DIDs to another PRI. There are also layer 1 switches that can detect when a circuit is down and physically switch over to another port. This method can be used for a more cost effective active/standby configuration, because now you don't have to subscribe to two or more PRI circuits if you don't have that kind of call volume. There is also some information regarding these devices in the wiki. http://www.voip-info.org/tiki-index.php?page=Failover%20switches The other side of the equation is what to do with the PBX->phone connectivity. So here, the problem is that a SIP phone will try to register or is already registered at pbx1.domain.com to make and receive calls, but if that pbx is down and the calls have been rerouted to another PRI, where and when should the phone try to register next? There are a few ways to get around this, one is to use DNS-based redirection based upon your PRI failover pattern, other people are using layer 4-7 switched like Foundry's Serveriron products that employ different virtualization techniques, and some phones like the Cisco 79x0 and the Polycom Soundpoints have the ability to register with a primary and backup sip servers. Once you have the phones registered to the right place, your users should be able to make and receive calls as usual. Networked storage of certain data and a little creativity with the configuration files should allow them continual access to their voicemail and other user specific data. All in all, there are no standardized methods of achieving High Availability with asterisk alone. Conversely there are several methods of using asterisk with other technologies that can achieve your expected level of availability. Just like many other open-source technologies, you will have to closely evaluate what you need and determine what 'solution' will work best for you. -----Original Message----- From: asterisk-users-admin@lists.digium.com [mailto:asterisk-users-admin@lists.digium.com] On Behalf Of Steven Critchfield Sent: Wednesday, August 04, 2004 5:31 AM To: asterisk-users@lists.digium.com Subject: Re: [Asterisk-Users] Making asterisk distributed On Wed, 2004-08-04 at 09:30, Jeremy McNamara wrote:> Trilogy India wrote: > > > Hi, > > > > I want to know, if someone has tried to use clustering > > in asterisk to increase its scalability and make it > > distributed?? > > > > If yes, how easy it is to cluster? > > > > Can someone please ive me details about the same > > > Asterisk will not benefit from clustering.Not in the HPC sense, but it will in the high availability sense. -- Steven Critchfield <critch@basesys.com> _______________________________________________ Asterisk-Users mailing list Asterisk-Users@lists.digium.com http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users