s flowing). We've already talked about what QoS cannot do. One of the big things that QoS cannot do is resolve a need for more bandwidth. This link is clearly in need of a larger pipe because we're dropping more than 10 percent of all packets sent from Building A to Building B. In this case, the only ways to prevent these packets from being dropped is to install a larger link between the buildings, or stop sending SO much data. Resolving the Problem What we can use QoS to do is determine more specifically what packets should and should not be dropped. (See Chapters 29 and 30 for more information on designing a QoS scheme.) Let's clear those counters now, SO that the next time we look we'll have some fresh data: Bldg-A-Rtr# clear counters so/o Clear "show interface" counters on this interface [confirm] And on the other side as well: Bldg-B-Rtr# clear counters so/o Clear "show interface" counters on this interface [confirm] If you think you need a larger link, you will need to collect some real data to support your case. When you approach management with your concerns, having informa- tion similar to what I've shown you in this chapter will help justify the expense of more bandwidth. SNMP network monitoring is one of the most useful tools you can deploy on your network. You don't need fancy systems like CiscoWorks or Open- View, though if you can afford those tools, they are worth having. Free tools such as the MRTG are very powerful and useful, especially for justifying larger links. Chapter 31: The Congested Network CHAPTER 32 The Converged Network In this chapter, you'll see a converged network in action. While the network will be very simple, the principles shown will scale to networks and links of almost any size. Figure 32-1 shows the network we'll use for the examples in this chapter. R1 and R2 each have two Ethernet networks attached: one with an IP phone, and one with a per- sonal computer. The routers are connected with a T1 that terminates into S0/1 on each. 10.1.1.1/24 10.3.3.3/24 192.168.1.0/24 10.2.2.