BROCADE IP PRIMER

Chapter Review Questions• Direct Server Return (DSR) changes only the destination MAC address ofthe incoming packet; it does not see the outgoing packet— DSR requires all physical servers to have a loopback address configuredwith the same IP address as the VIP— In DSR, the outgoing packet (the reply from the server) travelsdirectly from the server to the original client; the load balancer doesnot see the reply• Health check is the method the load balancer uses to make sure a physicalserver may receive incoming traffic— Active health checks are categorized as either initialization orperiodic— A Layer 3 health check uses ARP and ICMP echo (“ping”) to see if ahost is active— A Layer 4 health check for TCP uses a modified three-way handshake- SYN - SYN/ACK - RST— A Layer 4 health check for UDP sends a segment, and looks for anICMP “Port unreachable” message; if it doesn't see this message,the server is active; if it does see the message, the server is inactive— A Layer 7 health check uses a user-defined Application-layer requestto see if the server responds properly— If a Layer 4 health check is defined, a Layer 3 health check will beperformed also— If a Layer 7 health check is defined, a Layer 3 and Layer 4 healthcheck will be performed also• Active/Standby Redundancy requires two or more load balancers; onlyone load balancer will actively listen for the VIP at any time.• Active/Active Redundancy requires two or more load balancers; oneActive/Active method involves multiple Active/Standby VIPs, requiring twoor more VIPs; “true Active/Active” requires only one VIP, but only one loadbalancer actively listens for the VIP.Chapter Review Questions1. Which load balancing method will give your end users the greatest bandwidthand number of sessions?a. SLBb. DSRc. Source NATd. ProxyBrocade IP Primer 111