<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 TRANSITIONAL//EN">
<HTML>
<HEAD>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=UTF-8">
<META NAME="GENERATOR" CONTENT="GtkHTML/3.14.1">
</HEAD>
<BODY>
On Fri, 2007-10-26 at 08:21 +0200, Kristian Nielsen wrote:
<BLOCKQUOTE TYPE=CITE>
<PRE>
<FONT COLOR="#000000">Mostafa Ibrahim <<A HREF="mailto:mostafa.ibrahim@valuesys.net">mostafa.ibrahim@valuesys.net</A>> writes:</FONT>
<FONT COLOR="#000000">> I found that chan_ss7 has some clustering support starting from version 0.8.</FONT>
<FONT COLOR="#000000">> This is the feature as mentioned in the read me file "Supports multiple hosts</FONT>
<FONT COLOR="#000000">> (cluster) configuration with load sharing and failover". Which is exactly what</FONT>
<FONT COLOR="#000000">> I need. Has anyone tested this configuration.</FONT>
<FONT COLOR="#000000">></FONT>
<FONT COLOR="#000000">> What I understood from the configuration templates included with the source</FONT>
<FONT COLOR="#000000">> code that the interconnect will not only be used for keep alive "heart beats"</FONT>
<FONT COLOR="#000000">> it will also carry the signaling between the nodes which means that the</FONT>
<FONT COLOR="#000000">> signaling might terminate on one host and be used on an other node passing</FONT>
<FONT COLOR="#000000">> through the interconnect which is the perfect solution to my problem.</FONT>
<FONT COLOR="#000000">Yes, this is basically correct.</FONT>
<FONT COLOR="#000000">>From the start, chan_ss7 was designed for full support of MTP3 failover and</FONT>
<FONT COLOR="#000000">fault tolerance. Thus the purpose of implementing clustering was primarily to</FONT>
<FONT COLOR="#000000">enable the setup of a system with no single point of failure. So cable</FONT>
<FONT COLOR="#000000">failure, host crash, or even a dead network switch will not lead to any</FONT>
<FONT COLOR="#000000">downtime (except loosing a few existing calls currently running on affected</FONT>
<FONT COLOR="#000000">curcuits).</FONT>
<FONT COLOR="#000000">Thus, while the basic facilities are there for routing the signalling across</FONT>
<FONT COLOR="#000000">the interconnect, it was never intended for a setup with only one signalling</FONT>
<FONT COLOR="#000000">link, so currently that may not work very well.</FONT>
<FONT COLOR="#000000">I would also think that with ~900 phone lines, you _would_ want some kind of</FONT>
<FONT COLOR="#000000">redundancy? Otherwise just the need to switch cabling or reboot the host</FONT>
<FONT COLOR="#000000">carrying the link will take down _all_ 900 lines! With two links, one on each</FONT>
<FONT COLOR="#000000">host, you can just set the lines on one host to maintenance mode, wait for</FONT>
<FONT COLOR="#000000">existing calls to end, then reboot/recable/whatever with no noticable effect</FONT>
<FONT COLOR="#000000">on users. This also holds true for the other end, who might assume this</FONT>
<FONT COLOR="#000000">functionality (as it is a mandatory part of the SS7 specs).</FONT>
</PRE>
</BLOCKQUOTE>
<BR>
I might ask the provider to provide me with another redundant signaling channel on another E1 line which should be on the other server.<BR>
<BR>
<BLOCKQUOTE TYPE=CITE>
<PRE>
<FONT COLOR="#000000">Also, I think the clustering still only supports two hosts. So you could put 4</FONT>
<FONT COLOR="#000000">quad-span cards into each server (4 PCI slots should be possible I guess), but</FONT>
<FONT COLOR="#000000">I don't know if/how Asterisk will handle that many simultaneous lines.</FONT>
<FONT COLOR="#000000">Maybe if the SS7 boxes do nothing but route over IAX to a larger number of</FONT>
<FONT COLOR="#000000">Asterisks that do the real work (transcoding, SIP, DB auth, whatever) it would</FONT>
<FONT COLOR="#000000">increase the chance of Asterisk being able to cope with 450 lines? But that is</FONT>
<FONT COLOR="#000000">just speculation on my part.</FONT>
</PRE>
</BLOCKQUOTE>
<BR>
This is typically what I planning to do. The first tier asterisk servers will carry out routing only and their will be a second tier servers containing the business logic of the IVR applications and other database servers if needed by certain application. The dimensioning of the first tier servers might enforce me to buy an 8 processors dual core with 64 GB RAM for example which is not a big deal in such huge deployments. <BR>
<BR>
I want to use the current implementation as a base to start developing a mechanism to distribute "SS7 signaling over IP". Thus I can receive the SS7 signaling on any channel on any E1 link on any host and then implement a client server message bus that can be used to distribute these signaling among multiple hosts. Thus other hosts will set all their channels to voice channels and get the ss7 signaling through the message bus.<BR>
<BR>
There might be an opensource implementations for such tcp/ip communications that can be directly included (multicast implementation will be suitable). The main issue it to implement the hooks inside the chan_ss7 code to deal with this message bus. I think the starting point is to extend the current implementation of cluster_send_packets and cluster_receive_packets functions to deal with this bus. <BR>
<BR>
<BLOCKQUOTE TYPE=CITE>
<PRE>
<FONT COLOR="#000000"> - Kristian.</FONT>
<FONT COLOR="#000000">_______________________________________________</FONT>
<FONT COLOR="#000000">--Bandwidth and Colocation Provided by <A HREF="http://www.api-digital.com">http://www.api-digital.com</A>--</FONT>
<FONT COLOR="#000000">asterisk-ss7 mailing list</FONT>
<FONT COLOR="#000000">To UNSUBSCRIBE or update options visit:</FONT>
<FONT COLOR="#000000"> <A HREF="http://lists.digium.com/mailman/listinfo/asterisk-ss7">http://lists.digium.com/mailman/listinfo/asterisk-s</FONT>s7</A>
</PRE>
</BLOCKQUOTE>
<TABLE CELLSPACING="0" CELLPADDING="0" WIDTH="100%">
<TR>
<TD>
<TABLE CELLSPACING="0" CELLPADDING="0" WIDTH="100%">
<TR>
<TD>
=================================<BR>
<B><FONT SIZE="4">Mostafa Ibrahim </FONT></B><BR>
Security Department Manager<BR>
ValueSyS<BR>
<I>website: </I><I><FONT COLOR="#0000ff">http://www.valuesys.net </FONT></I><BR>
<I>Tel: +202 22682552 +202 2682887</I><BR>
<I><FONT SIZE="2"><FONT COLOR="#000000">Fax: +202 22674346</FONT></FONT></I><BR>
<I>Mobile: +2 0181008194</I><BR>
<I>Email: mostafa.ibrahim@valuesys.net</I><BR>
=================================
</TD>
</TR>
</TABLE>
</TD>
</TR>
</TABLE>
</BODY>
</HTML>