MICROSOFT NLB on satck ERS4800 with ip routing activate

[EF]

Hi team,

in ERS4800 stack doing ip routing between servers and user we need deploy two server with MICROSOFT NLB in multicast mode.

I found this document that describes this scenario on section 2.2:

https://documentation.extremenetworks.com/TCG-TSG/NN48500-593_MSNetworkLoadBalancing__SRG_Feb2014.pdf

But I´m confused about the config describes the section 2.2.2, as a "mandatory configuration steps" :

"No mandatory configuration steps need to be performed. By default Avaya Ethernet switching platforms will flood Network Load Balancing cluster traffic with no additional configuration being required."

but in "optional configuration steps":

"If Network Load Balancing clusters are deployed using multicast or IGMP-multicast modes, administrators must create a static ARP entry on the core mapping the multicast MAC address to the server VLAN and server switch uplink port."

So, Will it works with no configuration or optional config is needed? Has someone experience with this config?

Thanks in advance.

EF

[Ludovico_Steven]

If you have both NLB servers plugged into the same ERS, then this ERS has to act as L2 for that NLB VLAN.
If you give this ERS an IP address to act as gateway on this VLAN, then when routing packets into the NLB VLAN towards the NLB Cluster IP, it will not replicate a copy to both servers, and NLB won't work.
You would need to have a separate ERS acting as the IP router for this VLAN and connected to the 1st ERS via 1 physical (or logical, MLT) connection. This way, the 2nd ERS routes the packet out of its single port to the 1st ERS and the 1st ERS then floods the packet to all NLB Servers in the VLAN.
It's convoluted, because ERS was never expressly designed to support Microsoft NLB.
If you take a VOSS VSP, it has Microsoft NLB support (Unicast and Multicast modes - except VSP4450/4850 models) and you can NLB-enable the VLAN, have servers directly connected and an VSP IP interface on the same VLAN.

[EF]

Hi Ludovico,

Yes, it see the port 2/7 because is its own port, sorry but the L2 and L3 is made for the same stack or ERS4800 in which are plugged both servers.

Sorry but I´m very confused about the config or support of this topology.

Regards,

EF

[Ludovico_Steven]

Oh ok, I thought that would require static ARP config.
But you see that port 2/7 ?
The ERS is not going to flood packets in the VLAN when it uses that ARP record.
It will only send one copy of the multicast packet out of port 2/7.

To your question, yes you can do that. But who is going to IP route packets to/from that VLAN ? It cannot be the same ERS.

[EF]

Thanks Ludovico, the NLB mode is multicast but the ARP entry is learnt by the ERS4800 stack:

STACK1#show arp 172.A.B.C
===============================================================================
IP ARP
===============================================================================
IP Address Age (min) MAC Address VLAN-Unit/Port/Trunk Flags
-------------------------------------------------------------------------------
172.A.B.C 0 03??ac:1b:0a:0f VLAN#10-2/7 D
Total ARP entries : 1
-------------------------------------------------------------------------------
Flags Legend:
S=Static, D=Dynamic, L=Local, B=Broadcast, V=VRRP, v=VRRPOwner

But anyway, Could the recomentadion be to put both servers with Multicast mode in an isolated VLAN and ERS with no config as I understand?

Regards,

EF