[c-nsp] network design question

[Mark Tohill]

Scott,

We have a similar requirement to have dual-homed servers. It sounds as if the SQL issue with dual IP's is a no-goer. If you're VLAN's (assuming you have them) span the network, then you'll have L2 connectivity between the two core switches with ability to carry VLAN's. i.e. a trunk.

If you use something like HP's Network Fault Tolerance (they have a few flavours) on the NIC's, they use the same IP with active/standby scenario. Each NIC connected to different switch. In our case, these are connected to access switches which have, in turn, resiliency to core/distribution switches. The fact that you're going directly into core switches doesn't make a difference.

HTH, Mark

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

Message: 6
Date: Thu, 7 Sep 2006 09:34:05 +0200
From: "Brian Turnbow" <b.turnbow at twt.it>
Subject: Re: [c-nsp] network design question
To: "Scott Granados" <sgranados at jeteye.com>,    "Cisco-NSP Mailing List"
        <cisco-nsp at puck.nether.net>
Message-ID:
        <F2207DB22012F94E92D7030F81A26294080109 at twt-exch.milano.twt>
Content-Type: text/plain;       charset="iso-8859-1"

Another approach is to use ospf (or even bgp)and a loopback address on the server.
Take a look at zebra http://www.zebra.org/
You can tune it for failover or load balancing between the switches.

 Brian

-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Scott Granados
Sent: mercoled? 6 settembre 2006 21.11
To: Cisco-NSP Mailing List
Subject: [c-nsp] network design question

Hi, I'm looking for some pointers on what technology or methods to use
here.



I'm designing a new network for my company and have run in to a problem
which I'm sure a solution exists to address but I didn't know where to
start.  I have two core switches (4506's) each with supervisor 4's
(wsx4515) and each has 3 wsx4548 cards installed making a total of 144
ports each.  Now, much of our architecture has several servers so for
example, we might have 4 application servers.  My plan was to place 2 on
switch a and two on switch b so if either switch fails, I only lose part
of my application serving ability.  However, suppose we have a master
mysql server but it's only attached to switch a.  If switch a dies then
the entire application dies as there is no path for data.  My servers
all have 2 gig NIC's.  Would it be possible to attach the mysql master
to both A and B and use some method that allows either card to be
reached by the same IP.  Clearly, having two ips would be simple but our
application does not have a means to connect to more than one DB.  Is
there a clean way that say switch A dies so then nic A no longer
functions so nic B takes the remaining traffic left on switch B headed
for the same ip of the database master?  What are people using for fail
over in the event of switch failures?



Thanks





G. Scott Granados

Sr. Network Operations Specialist

OFFICE: 415-946-2112 EXT. 222

CELL: 408-569-4017

URL: http://www.jeteye.com



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