Re: NLB's Multicast MAC Address

Peter W. wrote:
> Network Load Balancing uses a Multicast MAC address to
> communicate. How do I find out what NLB is using for the
> multicast MAC? Is it the Network Address under the Cluster
> Properties ==> Cluster Parameters of the NLBMGR? If so,
> does this remain constant even if the Cluster Master (host
> priority 1) fails?
>
> The reason that I am asking is that we are using IBM
> servers, Intel Teaming, Cisco Swithes and Routers and the
> documentation says that I might need to use static arp
> entries because of a known issues with Cisco IOS and
> Multicast MAC addresses communicating with Unicast IP
> addresses.
>
> Thanks,

That is the MAC you will need, and yes it stays constant within the NLB
cluster. You will need to add a static ARP in your Cisco router to that MAC
in order to get traffic to it. I also recommend you have a independent
cluster switch.

--
Regards,

Michael Holzemer
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>-----Original Message-----
>Peter W. wrote:
>> Network Load Balancing uses a Multicast MAC address to
>> communicate. How do I find out what NLB is using for the
>> multicast MAC? Is it the Network Address under the Cluster
>> Properties ==> Cluster Parameters of the NLBMGR? If so,
>> does this remain constant even if the Cluster Master (host
>> priority 1) fails?
>>
>> The reason that I am asking is that we are using IBM
>> servers, Intel Teaming, Cisco Swithes and Routers and the
>> documentation says that I might need to use static arp
>> entries because of a known issues with Cisco IOS and
>> Multicast MAC addresses communicating with Unicast IP
>> addresses.
>>
>> Thanks,
>
>That is the MAC you will need, and yes it stays constant
within the NLB
>cluster. You will need to add a static ARP in your Cisco
router to that MAC
>in order to get traffic to it. I also recommend you have a
independent
>cluster switch.
>
>--
>Regards,
>
>Michael Holzemer
>No email replies please - reply in newsgroup
>
>Learn script faster by searching here
>http://www.microsoft.com/technet/tre...er/default.asp
>
>
>
>.
>When you say independent switch, do you mean a switch
dedicated to NLB. If so, would a VLAN do?

Peter W wrote:
> > -----Original Message-----
> > Peter W. wrote:

<snip>

> > When you say independent switch, do you mean a switch
> dedicated to NLB. If so, would a VLAN do?

That is exactly what I mean and yes a VLAN does very nicely. The reason I
say this is because of induced switch flooding by the NLB traffic.

--
Regards,

Michael Holzemer
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>-----Original Message-----
>Peter W wrote:
>> > -----Original Message-----
>> > Peter W. wrote:
>
><snip>
>
>> > When you say independent switch, do you mean a switch
>> dedicated to NLB. If so, would a VLAN do?
>
>That is exactly what I mean and yes a VLAN does very
nicely. The reason I
>say this is because of induced switch flooding by the NLB
traffic.
>
>--
>Regards,
>
>Michael Holzemer
>No email replies please - reply in newsgroup
>
>Learn script faster by searching here
>http://www.microsoft.com/technet/tre...er/default.asp
>
>
>
>.
>New Question: Can the NLB multicast MAC address be
manually set? The reason that I ask is because we have
added static arp enties for each VIP to our routers and
would like to be reassured that we would always know the
active/current multicast MAC.

Thanks,

(E-Mail Removed) wrote:
> New Question: Can the NLB multicast MAC address be
> manually set? The reason that I ask is because we have
> added static arp enties for each VIP to our routers and
> would like to be reassured that we would always know the
> active/current multicast MAC.
>
> Thanks,

No. The only way to change it is to change the load balancing parameters.

--
Regards,

Michael Holzemer
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