Win2k3 NLB Unicast vs. Multicast

[Dan Foxley]

Howdy,

NLB cluster in development quit working in the default setting of Unicast
and now works in Multicast (IGMP). What is the way I need to configure
this?
I've read ALOT and am now well confused, please help on questions below.

2- Win2k3 WebEdition
2- Servers with 2 Nics each (2 subnets)
NLB goes into a hub
Mang. Lan goes into a swich

I will use this for a redunadant www front end, more so than for traffic at
this point, and go into a SQL backend.

1. Do I use Unicast or Multicast (if multicast do I use IGMP?)

2. Do I need a hub on the NLB Nics?

3. What about ARP entries or the Registry hack that mask the ARP?

4. I've read confilicting Default Gateway suggestions, all three
options---only on NLB, only on the Mang. NICS, or both is OK. Which one?

5. Do I even need two NICS? Should I just team both NICS as NLB?

TIA
Dan Foxley

[Joseph Joy [MSFT]]

Hi Dan,

for most people, the default (Unicast) works just fine. Layer 3 switches
will not work with NLB unless the specific ports are configured to operate
in Layer-2 mode -- typically the ports that are going to be part of NLB are
configured as a VLAN and those ports setup to operate in Layer-2 mode.
Unfortunately the actual mechanism of configuring this depends is
switch-manifacturer specific. You do not need a hub if you can set this up.
If you don't have this flexiblity with the switch, then you can connect the
two nodes to a hub and set the MaskSourceMac registry key to 0.

The only reason to use Multicast is to minimize switch flooding, which will
be an issue if you expect large volumes of inbound traffic; Multicast has
interop problems with certain Routers, requiring the routers to be setup
with static ARP entries, which can be cumbersome to administer.

On Server2003, there are no specific recommendations for Gateway and NLB
(typically the "management NIC" is used for management purposes only, so it
wouldn't make sense to route outbound traffic via that NIC).

Unfortunately, NIC teaming does not play well with NLB -- if you do decide
to go that route, you should make sure that the teaming NIC vendor has
endorsed use of it's product with NLB and has specific guidelines on how to
use the teaming configuration software with NLB.

Regards,

Joseph.
--

Joseph Joy
Software Design Engineer
Windows Server Group, Microsoft
This posting is provided "AS IS" with no warranties, and confers no rights.

"Dan Foxley" <dfo...@pacificdatavision.com> wrote in message
news:OFmwS2uf...@TK2MSFTNGP11.phx.gbl...

[Dan Foxley]

You mention if I use a hub to set: MaskSourceMac = 0. Is this why Unicast
did not work for me because I DID not adjust this reg key when using a hub
with unicast?

I used a hub because I'm using a Non-Managed Switch and was concerned about
switch flooding. So I seperated the two nics in each host, to a switch and
hub. Any feedback on above?

TIA,
Dan Foxley

"Joseph Joy [MSFT]" <jos...@online.microsoft.com> wrote in message
news:OZPBDyTg...@tk2msftngp13.phx.gbl...