Subject: I've been wondering if

From: Manoj Dhooria <[email-masked]>
Date: Wed, 31 Jan 2001 15:30:58 +0530

RSerPool gives me only server redundancy, or ISP redundancy too. Two are
really different sides of the same coin. I am kind of being forced to
introduce ISP redundancy into my server - essentially, two IP addresses that
access the SAME IDENTICAL SERVER PROCESS & ITS STATE ON THE SAME PHYSICAL
MACHINE ON SERVER LAN. Essentially saying a pool element PE1 is accessible
via two separate IP addresses - IP1 & IP2.

The reason I need this is as follows. I have a pre-production server product
running on my Bombay facilities, & corresponding pre-production clients on
the notebooks of sales staff - for demonstrations to early partners. I have
two independent ISPs serving my Bombay facilities - both have a tendency to
blank out every now and then. So I have two URLs which sales staff manually
switch when one doesn't work - something a little embarrassing in front of a
potential customer. Since both URLs essentially reach the same physical
server process, I can make their life somewhat easier if my client
automatically switches as necessary.

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From: "Randall R. Stewart" <[email-masked]>
Date: Wed, 31 Jan 2001 14:05:02 -0600

> automatically switches as necessary.

Here is why you want SCTP and why we specify this as the
transport of RserPool.  SCTP allows the transport association
to span both IP addresses. So if one of the ISP's fail, the
SCTP association does not but automatically retransmits the
request (or whatever) to the alternate address.

The fault tolerance issue is really two fold, one layer is
server redundancy... i.e. what happens when an individual
PE dies. The other is link redundancy, i.e. what happens when
I accidently kill one of the enet wires connecting my server?

The link layer SCTP handles
The PE layer ASAP handles..

The two together form a very powerful mechanism that solves
the problem...

R
--
Randall R. Stewart
[email-masked] or [email-masked]
815-342-5222 (cell) 815-477-2127 (work)