[isalist] Re: NLB Unicast and Multicast
- From: "Gerald G. Young" <g.young@xxxxxxxx>
- To: <isalist@xxxxxxxxxxxxx>
- Date: Tue, 19 Sep 2006 08:35:19 -0400
Multicast will get a bit hairy - not sure if ISA would like that or not.
The basic operation of unicast is that it replaces the physical IP and MAC
addresses with virtual ones. Thus, all the talk about needing two NICs
(changed in W2K3 SP1 through implementation of Reg Key) in order for the ISA
servers to talk to one another; since both machines have the same IP and MAC,
it's hard for them to distinguish themself from their cluster mate, if you will.
Multitask essentially operates where BOTH the physical IP and MAC address
exists concurrently with the virutal ones. That requires hard coding ARP
tables elsewhere in your network to ensure traffic gets to where it needs to go.
Finally, NLB type of multicast isn't the same as the network type of multicast,
where you're able to send a single bit stream that arrives at each location, I
don't think. For what I have seen, the only difference is the implementation
of the virutal IP and MAC address; unicast replaces physical, multicast shares
with physical.
Now, is there any reason you're looking to move to multicast NLB operation?
I've seen nothing but problems with it (because of the increased management
overhead) and I'm not sure what ISA would think if it saw two MAC addresses
tied to the same NIC.
Cordially yours,
Jerry G. Young II
From: D PIETRUSZKA USWRN INTERLINK INFRA ASST MGR
Sent: 2006/09/19 (火) 8:22
To: isalist@xxxxxxxxxxxxx
Subject: [isalist] NLB Unicast and Multicast
Hi isalist
I was doing some analysis of my network and I was wondering if I could change
the NLB on the ISAs to work in multicast mode.
It is supposed that NLB should be configured from the ISA itself, but there is
not option for multicast or unicast there, but of course that option exist if
you go to NLB on the NIC properties.
So, is there any problem on changing to multicast? There is any Microsoft
recommendation?
Thanks
Regards
Diego R. Pietruszka
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