ted? Let's look at our favorite two- building company again (Figure 31-1). Building A Building B Figure 31-1. Typical two-building network Users have been complaining that access to the other building is slow. So, let's take a look at the interfaces on one of the routers that connects the T1 between buildings. Here's the output from the show interface command for the serial interface on Building B's router: 1 Bldg-B-Rtr# sho int s0/0 2 Serialo/o is up, line protocol is up Hardware is PowerQUICC Serial Description: <[ T1 WAN Link ]> Internet address is 10.10.10.2/30 MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, reliability 255/255, txload 42/255, rxload 249/255 Encapsulation PPP, loopback not set Keepalive set (10 sec) LCP Open Open: IPCP, CDPCP Last input 00:00:00, output 00:00:00, output hang never Last clearing of "show interface" counters 3w4d Queueing strategy: fifo Output queue 0/40, 548941 drops; input queue 0/75, 3717 drops minute input rate 1509000 bits/sec, 258 packets/sec 5 minute output rate 259000 bits/sec, 241 packets/sec 287554125 packets input, 3659652949 bytes, 0 no buffer Received 0 broadcasts, 0 runts, 0 giants, 0 throttles 819 input errors, 559 CRC, 227 frame, 0 overrun, 0 ignored, 33 abort 282883104 packets output, 3613739796 bytes, 0 underruns 0 output errors, 0 collisions, 1 interface resets 0 output buffer failures, 0 output buffers swapped out 0 carrier transitions DCD=up DSR=up DTR=up RTS=up CTS=up Looking at this information, you should notice some things right away. First, this is a T1, and the bandwidth is 1,544 Kbps (lines 4 and 6). Remember that the bandwidth shown when using show interface is not necessarily representative of the true bandwidth of the link. While this value is correct by default, it can be changed with the bandwidth interface command. This field is used for calculations in EIGRP and other protocols, which is why it can be altered. Looking further down (line 16), you can see that the five-minute input rate is 1,509,000 bps, 258 pps. That's 1,509 Kbps used on a 1,544 