BROCADE IP PRIMER

Chapter 5: Load Balancing BasicsWhat type of health check have you just witnessed?a. Layer 3b. Layer 4c. Layer 7d. All of the above10. Which load balancing method requires the physical servers to be configuredwith a loopback?a. DSRb. SLBc. Source NATd. ProxyAnswers to Review Questions1. b. DSR uses the bandwidth of the individual server, not the load balancer.With SLB, Source NAT, and Proxy, all traffic travels into and out of the loadbalancer.2. c. With one VIP, you could either configure Active/Standby, or true Active/Active. In either case, only one load balancer actively listens for the singleVIP.3. d. Source NAT changes the incoming packet so that it appears to comefrom the load balancer to the physical server (rather than the client to theVIP). It has to appear to come from the load balancer, so that the returntraffic will come back through the load balancer as well.4. a. This is a TCP Layer 4 health check. The load balancer sends a TCP SYN.The physical server sends a TCP SYN/ACK. Then, the load balancer finishesthe discussion by sending a TCP RST (reset).5. b. The load balancer changes the destination IP and MAC address to bethe addresses of the physical server it has chosen (as opposed to theVIP).6. d. You could use Active/Standby, but if you have two VIPs, you would bewell-served to configure Active/Active.7. c. This is the way the load balancer will health check UDP. If it receives anICMP Port Unreachable message, it knows that the physical server is notlistening on the specified UDP port, and will mark the server inactive. Forthe UDP Layer 4 health check to succeed, the load balancer must sendthe UDP segment, and not receive any reply.8. a. In DSR, the load balancer only changes the destination MAC address tobe the MAC address of the physical server it has chosen.114 Brocade IP Primer