RE: [Serusers] forward() and t_relay() differences - sr-users

4 Oct 2004

At 01:04 AM 10/5/2004, Michael Shuler wrote:
...
 My intent is to do SIP load balancing using a layer 4
hardware switch (such
as a Foundry ServerIron XL) or a layer 4 software switch (such as
UltraMonkey).

Since SER *could* operate in a completely stateless mode it could serve as a
per packet proxy in front of a series of stateful feature servers such as
Asterisk.  A L4 device by itself would not be enough and a stateless MUST be
in front to do the actually balancing because of SIP's flaw/design of
containing routing information throughout the packets life.   
I don't think that this specific issue is SIP design flaw. It is coming
from the proxy mode which is useful for many reasons. Achieving consistency
with a proxy and load-balancer is not as easy as for banal request-response
apps like web.

...
 It would have
been nicer if it only carried a source and destination and worked more like
TCP/IP but unfortunately it is what it is.

Anyway, I about have everything working and I only seem to have a small
issue when the second SER server comes online with some strange message
passing between them.  Most of it I believe is caused by my lack of
understanding of how SER makes some decisions on where to send things.   
It depends on what you mean by things. If you mean log error than these
are sent to syslog. If you mean replies, their destination is governed
by RFC3261 and rport extensions. If you mean proxied requests, than
the destination is governed by routing script.

...
 I
think what would help is if I setup a "work in progress" web site that would
show all my config files and the layout of the whole thing along with an
explanation of why I decided to do what I did.  I should have it up later
today or tomorrow.

----------------------------------------

Michael Shuler, C.E.O.
BitWise Communications, Inc. (CLEC) And BitWise Systems, Inc. (ISP)
682 High Point Lane
East Peoria, IL 61611
Office: (217) 585-0357
Cell: (309) 657-6365
Fax: (309) 213-3500
E-Mail: mike(a)bwsys.net
Customer Service: (877) 976-0711 

> -----Original Message-----
> From: Jiri Kuthan [mailto:jiri@iptel.org] 
> Sent: Monday, October 04, 2004 5:42 PM
> To: Michael Shuler; serusers(a)lists.iptel.org
> Cc: jan(a)iptel.org
> Subject: RE: [Serusers] forward() and t_relay() differences
> 
> 
> At 07:50 PM 10/4/2004, Michael Shuler wrote:
> >Sorry if that first line sounded snotty, I didn't mean it 
> that way.  I
> >didn't read it until after I sent it.  What I meant to say 
> was thank you for
> >the response.
> 
> you are very welcome.
> 
> >  I had already been through the docs though and found that too
> >but I was still seeing the following problem..
> 
> I am interestd in more feedback on load-balancers. To my 
> knowledge, it is
> a technology which has some conflicts with SIP protocol and 
> those LBs that
> try to fix the problems using built-in SIP awareness don't do 
> necessarily
> any better. We are working on a SER built-in load-balancing 
> architecture
> but that's still work in progress.
> 
> -jiri
>  
--
Jiri Kuthan            http://iptel.org/~jiri/ 