k - Skinny media, M - SMTP data, m - SIP media, 0 - outbound data, P - inside back connection, q - SQL*Net data, R - outside acknowledged FIN, R - UDP RPC, r - inside acknowledged FIN, S - awaiting inside SYN, S - awaiting outside SYN, T - SIP, t - SIP transient, U - up TCP outside: :10.46.109.49/1863 inside:LAB-PC2/1736 flags UIO TCP outside: 10.188.8.176/5190 inside: LAB-PC/4451 flags UIO TCP outside: 10.241.244.1/48849 inside: :LAB-SVR1/80 flags UIOB UDP outside: 10.30.70.56/161 inside:RTR1/1031 flags - Chapter 26: PIX Firewall Configuration PART VI Server Load Balancing This section is designed to give you a quick view into the world of server load bal- ancing. It reviews server load-balancing technology, and shows examples regarding real-world implementations. This section is composed of the following chapters: Chapter 27, Server Load-Balancing Technology Chapter 28, Content Switch Modules in Action CHAPTER 27 Server Load-Balancing - Technology Server load balancing (SLB) is what enables multiple servers to respond as if they were a single device. This idea becomes very exciting when you think in terms of web sites, or anywhere a large amount of data is being served. Large web sites can some- times serve gigabits of data per second, while most servers as of this writing can only provide a gigabit at a time at the basic level. EtherChannels (trunks in Sun Solaris parlance) can increase that rate, but the real issue becomes one of power and scalability. Having many smaller, less expensive web servers is often more viable financially than having one large, extremely powerful server. Additionally, the idea of high availability comes into play, where having multiple smaller servers makes a lot of sense. Figure 27-1 shows a simple load-balanced network. Internet Firewall 10.5.5.0/24 6509 with Content Switch Module (CSM) 10.10.10.0/24 HTTP web servers HTTP content servers Figure 27-1. Simple load-balanced network Within Figure 27-1, there is one feed to the Internet, with six servers behind a fire- wall. The device