He seems to be talking about some kind of load balancing device like a Cisco
Local Director or something from Foundry.

What puzzles me is the next part

> >Even "session" level stuff like cookies and whatnot can be handled by
> >these switches, to make sure your session stays on the same server.

I know this works partially with the Local Director.  However, things like
SSL do not work properly with such a scenario.


----- Original Message -----
From: "Priscilla Oppenheimer" <[EMAIL PROTECTED]>
To: "Brian" <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>
Sent: Friday, October 13, 2000 1:54 PM
Subject: Re: High Availability. (Maybe OT)


> Who makes Layer 4 switches such as what you're talking about, Brian? Sorry
> if it's a dumb question.
>
> I'm helping a customer who has a setup similar to what you describe, I
> think. The customer is reluctant (unable?) to give me all the details,
even
> though I'm helping him troubleshoot some problems that are probably
> related. (Layer 8, politics, will get you every time!)
>
> Thank-you for your help.
>
> Priscilla
>
>
> At 08:30 AM 10/13/00, Brian wrote:
> >Using Server Load Balancing on switches.  Then between the switches you
> >run a hot standby protocol.  For example:
> >
> >The ip the clients use for the server would really be a "virtual" ip
> >address, which is actually bound to the layer4 switch.  The layer 4
switch
> >receives requests for the application (lets say port 80) and then load
> >balances accross a server farm using a hash table.  If servers
die......it
> >can handle this, because it does health checks to the servers.  If the
> >switch dies, then hot standby kicks in and another switch is activated.
> >
> >Even "session" level stuff like cookies and whatnot can be handled by
> >these switches, to make sure your session stays on the same server.
> >
> >Other applications like databases etc, have similar scenerios.  Normally
> >in the above scenerio, you backend all the servers off a single file
> >server so that the data is the same on all servers (NFS).  This file
> >server would be a high reliable server such as a NetApp
> >
> > >
> >
> > >
> > > Problem, maintaing the same layer 3 address accross both switches in
> > > the advent that one link should fail, the server maintains
> > > reachability.
> >
> >
> >
> > >
> > > Giving that in this case I would be talking about a solaris system, I
> > > have thought about using simple scripts to watch for the interface to
> > > go down and reconfigure.  I am curious if anyone knows of any
> > > hardware/software solutions for doing this?  I am guessing that I am
> > > not the first person to ask for something like this.
> >
> >Brian
> >
> >
> > >
> > > -- Kevin
> > >
> >
> >-----------------------------------------------
> >Brian Feeny, CCNP, CCDP       [EMAIL PROTECTED]
> >Network Administrator
> >ShreveNet Inc. (ASN 11881)
> >
> >_________________________________
> >FAQ, list archives, and subscription info:
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> >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
>
>
> ________________________
>
> Priscilla Oppenheimer
> http://www.priscilla.com
>
> _________________________________
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