I have a question regarding to the NLB clusters in Windows. What I'd like to know is what kind of information is exchanged between nodes in the cluster? i.e. the NLB traffic.
Also I'd to clarify a few things about the two modes: unicast and multicast.
In unicast mode, the cluster's MAC is masked for all outgoing traffic. Since the switch hasn't registered this MAC address, port flooding is induced. So with unicast mode, two members cannot communicate with one another as the NLB adapters has the same MAC address. For members to communicate with one another, a second adapter is required in this scenario.
1. So what exactly is this NLB traffic for and whom communicates on the NLB interface?
2. How would I physically setup clustering in unicast mode? Setting up to a cluster with two members on the same switch would cause all sort of issues as the MAC address are exactly the same .
In multicast modes, each member has it's own MAC and a virtual MAC for the cluster. The virtual MAC address for the cluster is a multicast address, so sending frames to the address should induce NLB traffic to flood through ports. Since the switches have a unique MAC address, they can communicate with one another directly. Due to having a multicast address in ARP replies, some routers will reject this frames and a static arp entry will be required to resolve this issue.
1. In multicast mode, would be possible to have the exact same NIC for NBL traffic as a means of cluster member communicating with one another?
2. In terms of of performance, which is better unicast or multicast? And how is performance improved?
3. With multicasting, will switches do the exact same things as broadcasting unless configured to do so? i.e. I'll have to configure the switches to send packets to stations in the multicast group.
Thank you in advance.