EIGRP基本实验与度量计算(4)

　　R3#show interface s 1

　　Serial1 is up, line protocol is up

　　Hardware is HD64570

　　Internetaddress is 20.20.20.2/24

　　MTU 1500 bytes, BW 64000 Kbit, DLY 20000 usec,

　　reliability 255/255,txload 1/255, rxload 1/255

　　Encapsulation HDLC, loopbacknot set

　　Keepalive set (10 sec)

　　Last input 00:00:00, output 00:00:04, output hang never

　　Last clearing of "show interface" counters never

　　Input queue: 1/75/0/0 (size/max/drops/flushes); Total output drops: 0

　　Queueing strategy: weighted fair

　　Output queue: 0/1000/64/0 (size/max total/threshold/drops)

　　Conversations 0/1/256 (active/max active/max total)

　　Reserved Conversations 0/0 (allocated/max allocated)

　　Available Bandwidth 48000 kilobits/sec

　　5 minute input rate 0 bits/sec, 0 packets/sec

　　5 minute output rate 0 bits/sec, 0 packets/sec

　　4161 packets input, 269672 bytes, 0 no buffer

　　Received 1447 broadcasts, 0 runts, 0 giants, 0 throttles

　　0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort

　　4164 packets output, 270104 bytes, 0 underruns

　　0 output errors, 0 collisions, 4 interface resets

　　0 output buffer failures, 0 output buffers swapped out

　　1 carrier transitions

　　DCD=up DSR=up DTR=up RTS=up CTS=up

　　R3#

　   因为可靠性和负载是动态的度量，这种算法不允许链路上有突然的大的流量变化和出错率，这样会造成整个网络结构的不稳定，如流量的突然降低可能会导致路由器触发一个更新，为了防止度量的频繁改变，采用5秒种更新一次的方式。

　　大流量通过路由器的接口将会导致路由器的负载加大，如下所示，当CPU的利用上升超过70%以上的时候不同种类的路由器会相续选择丢包处理，当一直处了90%或者更高的时候，路由器将无法正常转发或导致死机。

　　R2#show int s 1

　　Serial1 is up, line protocol is up

　　Hardware is HD64570

　　Internetaddress is 10.10.10.2/24

　　MTU 1500 bytes, BW 64 Kbit, DLY 1000 usec,

　　reliability 255/255,txload 63/255, rxload 59/255←有流量通过时，负载增大。

　　Encapsulation HDLC, loopbacknot set

　　Keepalive set (10 sec)

　　Last input 00:00:03, output 00:00:00, output hang never

　　Last clearing of "show interface" counters never

　　Input queue: 1/75/0/0 (size/max/drops/flushes); Total output drops: 0

　　Queueing strategy: weighted fair

　　Output queue: 0/1000/64/0 (size/max total/threshold/drops)

　　Conversations 0/1/256 (active/max active/max total)

　　Reserved Conversations 0/0 (allocated/max allocated)

　　Available Bandwidth 48 kilobits/sec

　　5 minute input rate 15000 bits/sec, 2 packets/sec

　　5 minute output rate 16000 bits/sec, 2 packets/sec

　　4678 packets input, 494690 bytes, 0 no buffer

　　Received 1555 broadcasts, 0 runts, 0 giants, 0 throttles

　　1 input errors, 1 CRC, 0 frame, 0 overrun, 0 ignored, 1 abort

　　4670 packets output, 494456 bytes, 0 underruns

　　0 output errors, 0 collisions, 2 interface resets

　　0 output buffer failures, 0 output buffers swapped out

　　8 carrier transitions

　　DCD=up DSR=up DTR=up RTS=up CTS=up

　　R2#

　　因链路错误和波动导致可靠性下降，如下所示。

　　R2#show int s 1

　　Serial1 is up, line protocol is up

　　Hardware is HD64570

　　Internet address is 10.10.10.2/24

　　MTU 1500 bytes, BW 64 Kbit, DLY 1000 usec,

　　reliability 254/255, txload 15/255, rxload 19/255 ←链路可靠性下降

　　Encapsulation HDLC, loopback not set

　　Keepalive set (10 sec)

　　Last input 00:00:02, output 00:00:02, output hang never

　　Last clearing of "show interface" counters never

　　Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0