[isalist] Re: Network Load Balancing And Network Hardware Recomendations
- From: "Dave May" <dave.may@xxxxxxxxxxx>
- To: <isalist@xxxxxxxxxxxxx>
- Date: Thu, 18 Jan 2007 13:12:27 -0500
FYI, the key to making multicast work well is to a) enable IGMP multicast in
NLB b) either enable IGMP snooping on your switch(es) or set a static entry.
Note that if your switches do not allow a unicast IP to ARP to a multicast MAC
(if I remember correctly) it isn't going to work right and the traffic will
flood across all ports. That last part caused me a major headache, which was
only resolved with a great deal of traffic sniffing via WireShark. Turned out
to be a bug in the switch firmware...
YMMV,
Dave.
________________________________
From: isalist-bounce@xxxxxxxxxxxxx [mailto:isalist-bounce@xxxxxxxxxxxxx] On
Behalf Of Gerald G. Young
Sent: Thursday, January 18, 2007 9:58 AM
To: isalist@xxxxxxxxxxxxx
Subject: [isalist] Re: Network Load Balancing And Network Hardware
Recomendations
Hmmm... I had no problem with ISA-integrated NLB with two VIPs (OWA) running
connected to a layer 3 switch (Cisco 6509). The SMTP Gateways (ISA on top of
IIS SMTP) in the same network segment and connected to the same layer 3 switch
also utilized ISA-integrated NLB and handled around 200K messages a day just
fine. But, we had front-end and back-end NICs on these boxes with both sides
connected to separate VLANs.
Interestingly enough, we had more problems with the setup when NLB was
configured for Multicast (each port sees two MAC addresses - physical/virtual)
and the MAC addresses were hardcoded into the network fabric.
Cordially yours,
Jerry G. Young II
Product Engineer - Senior
Platform Engineering, Enterprise Hosting
NTT America, an NTT Communications Company
22451 Shaw Rd.
Sterling, VA 20166
Office: 571-434-1319
Fax: 703-333-6749
Email: g.young@xxxxxxxx
From: isalist-bounce@xxxxxxxxxxxxx [mailto:isalist-bounce@xxxxxxxxxxxxx] On
Behalf Of D PIETRUSZKA USWRN INTERLINK INFRA ASST MGR
Sent: Thursday, January 18, 2007 7:19 AM
To: isalist@xxxxxxxxxxxxx
Subject: [isalist] Re: Network Load Balancing And Network Hardware
Recomendations
NLB doesn't work fine with Layer 3 switches and that is known since a bunch of
years ago.
The only thing you need is a plain layer 2 switch and your ISAs connected to
it, if you don't want to spend a lot of money, go for the Netgear GS605 which
is a $30 gigabit layer 2 switch.
Now, of course most (if not all of them) layer 3 switches are managed switches
so you can play with them and forward the traffic to all the ports on it.
But again, if budget is a concern then go for the Netgear I have some and work
great.
Regards
Diego R. Pietruszka
From: isalist-bounce@xxxxxxxxxxxxx [mailto:isalist-bounce@xxxxxxxxxxxxx] On
Behalf Of William Holmes
Sent: Wednesday, January 17, 2007 7:12 PM
To: isalist@xxxxxxxxxxxxx
Subject: [isalist] Re: Network Load Balancing And Network Hardware
Recomendations
Hello,
The switch that I am currently using is an HP ProCurve Switch Model 2824. The
issue that I have had previously was one of the switch shutting down the ports
due to the NLB Mac Address "jumping around" between different ports on the
switch. That problem occurred on a CISCO switch (don't remember the exact
model gbb something or other). If I understand things correctly (Note that I
did say IF) there are switch configuration issues that have to be addressed.
KB 193602 (posted incorrect number last time sorry) mentions one of them which
is issue with port flooding and suppressing this with VLANs.
My past experience using Switches with NLB on Windows NT and Windows 2000 was a
train wreck. The path of least resistance was a dumb hub between the nodes and
the switch that gave the switch a consistent view of the NLB cluster. That is
why I am currently using Unicast With a Hub as KB193602 indicates.
If I understand correctly I should be able to Mask the NLB Mac Address and
after doing so connect directly to a switch as a side effect of this any
request to the NLB cluster will be sent to all ports of the switch (port
flood). Thus traffic will be sent to any and all machines on the switch unless
you define VLANS.
As another option could use another L2 switch that only deals with my NLB and
have a single uplink just like my current hub has thus gaining gigabit full
duplex connections or would the port flooding also affect the upstream switch.
It doesn't seem like it should. The upstream switch would see something
answering on the NLB switch's port.
Will something like a Netgear GS105 work in this instance for testing purposes?
It's the Switch getting to smart for MY own good that I worry about which is
why I am asking these questions.
Thanks
Bill
________________________________
From: isalist-bounce@xxxxxxxxxxxxx [mailto:isalist-bounce@xxxxxxxxxxxxx] On
Behalf Of Jim Harrison
Sent: Wednesday, January 17, 2007 4:07 PM
To: isalist@xxxxxxxxxxxxx
Subject: [isalist] Re: Network Load Balancing And Network Hardware
Recomendations
"HP Procurve" - what?
That's a product line, not a switch model.
Also, you don't need to use a hub; a L2 switch generally works just fine.
The problem is when the switch tries to be too smart about L3 and ends up being
too smart for its own good.
From: isalist-bounce@xxxxxxxxxxxxx [mailto:isalist-bounce@xxxxxxxxxxxxx] On
Behalf Of William Holmes
Sent: Wednesday, January 17, 2007 11:55 AM
To: isalist@xxxxxxxxxxxxx
Subject: [isalist] Network Load Balancing And Network Hardware Recomendations
Hello,
This is possible a little off topic.
We currently use Windows Network Load Balancing for our Exchange and ISA
servers. Right now to avoid problems with our network switches I have a hub
between the NLB hosts and our Network Switches. This connection is therefore
limited to 100MB ½ duplex connections.
I have new hardware coming in that I need to use NLB on and I would like to
have an optimal configuration. I have taken a look at Microsoft KB 192602 and
am looking for further recommendations. Our network switches are HP Procurve.
Thanks
Bill
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