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New Member

MS NLB and Cisco Switch

Good evening with Microsoft Network Load balancing (in Multicast Mode)usually we set, on the same switch where there are plugged the two hosts balanced, mac-address-table static of the physical interface and the MAC address generated by Win NLB as below:

!

mac-address-table static 03bf.3e6c.e34e vlan 13 interface FastEthernet0/3 FastEthernet0/4

mac-address-table static 0014.384c.d12a vlan 13 interface FastEthernet0/3

mac-address-table static 0014.38ee.6997 vlan 13 interface FastEthernet0/4

!

where on interface Fa0/3 and Fa0/4 there are the physical network interfaces, an also active the MAC address generated by Microsoft NLB.

Now the two hosts balanced by Microsoft NLB are dislocated on two different switches, how can use mac-address-table static?

Any information that you can send me are welcomed.

Best Regards

--

Davide Sacca'

7 REPLIES
New Member

Re: MS NLB and Cisco Switch

Hello,

i suggest you to configure MS-NLB in "multicast igmp mode". Then the NLB multicast ethernet address will be 01-00-5e-xx-xx-xx : a valid ethernet multicast address.

Be carrefull, the aim of the NLB mac address is to flood the frames to the NLB cluster on all the vlan ! (so all the real servers receive the frames).

=> So you should put your NLB servers in a dedicated vlan in order to limit the NLB flooding.

Regards,

Mickael

New Member

Re: MS NLB and Cisco Switch

Hi Mickael,

thank very much for your suggestion, have you ever try to use Win NLB on two hosts plugged on two different switches?

I ask you this question, because I would a switch redundant solution, if a switch fail the NLB can forward session on the other host balnced, and plugged on the second switch.

I hope you can understand.

Best Regards

--

Davide

New Member

Re: MS NLB and Cisco Switch

Hello,

yes can do that, i have customers with this config (NLB in multicast igmp connected to several switches).

But don't forget to create a specific vlan and you can filter the vlan to limit the multicast flooding to backbone and server switches.

With this config, you not need to configure static mac-address entries. But you need to configure static arp entries in the router for the NLB adresses.

Regards,

Mickael

New Member

Re: MS NLB and Cisco Switch

Hi Mickael,

if I have understand well you suggest me to:

1) set on NLB in multicast igmp, on hosts balanced with Win NLB

2) create a specific VLAN to the hosts balanced with Win NLB

3) delete static mac-address entries from the switch where the hosts balanced with Win NLB are plugged

4) use on the router the IOS command:

c7200-B(config)#arp IP_use_by_BALANCE MAC_address_use_by_BALANCE arpa

I have only a problem with 2) because all the hosts that belong to the same network (as the hosts balanced) are also on the same VLAN.

Regards

--

Davide

New Member

Re: MS NLB and Cisco Switch

Hello, i don't understand very well your question.

If your question is about the IP adressing, you effectively need to create a new specific subnet for the new NLB vlan. And the you have to route this vlan with your inter-vlan router (and add the static arp entry on the inter-vlan router).

Notice that if you don't create a new NLB vlan (for example because you don't want to create a new subnet) it will work, but the NLB traffic will be flooded through all your lan. That's i don't recommend.

Regards,

Mickael

New Member

Re: MS NLB and Cisco Switch

Hi Mickael,

thanks very much for your suggestion, my Win NLB solution now is as described below:

-first Win Server balanced with NLB, plugged on a switch

-a second Win Server balanced with NLB, plugged on another switch

-the two switch are plugged on a C6509, where there is plugged also my ASA 5540 in router mode

-not set mac-address-table static on the switches

-I have put this command line:

arp dmz-zcom1 IP_used_by_Win_NLB MAC_ADDRESS_by_Win NLB alias

with this command line on ASA, the Win NLB platform is ok.

I can't create a new specific subnet for the new NLB vlan, you think my solution can degarde the switches where the hosts balanced are plugged?

Regards

--

Davide

New Member

Re: MS NLB and Cisco Switch

Hello,

great if it's working on your network :-)

I don't think it will degrate ou switchs performance ...

It may degrade the other hosts performance becouse nlb traffic is floode, for example PCs ...

But i see that's a dmz so i think it is very limited.

Regards,

Mick.

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