交换机MIB库中 MIB字符串对应的中文意思：

    ifIndex 端口索引号
    ifDescr 端口描述
    ifType 端口类型
    ifMtu 最大传输包字节数
    ifSpeed 端口速度
    ifPhysAddress 物理地址
    ifOperStatus 操作状态
    ifLastChange 上次状态更新时间

与流量相关的MIB字符串对应的中文意思： 

    ifInOctets 输入字节数         ifOutOctets 输出字节数
    ifInUcastPkts 输入非广播包数   ifOutUcastPkts 输出非广播包数
    ifInNUcastPkts 输入广播包数    ifOutNUcastPkts 输出广播包数
    ifInDiscards 输入包丢弃数      ifOutDiscards 输出包丢弃数
    ifInErrors 输入包错误数        ifOutErrors 输出包错误数

如何实现使用SNMP监控交换机端口带宽？
监控交换机端口带宽实际上就是监控端口入流量和出流量信息，若要监控端口流量信息就需要使用ifInOctets和ifOutOctets字符串；具体使用格式如下（手动获取端口流量,其中testPublic是community社区名称）：

        [root@localhost ~]# snmpwalk -v 2c -c testPublic 172.16.100.1 ifInOctets
        IF-MIB::ifInOctets.1 = Counter32: 0
        IF-MIB::ifInOctets.2 = Counter32: 0
        IF-MIB::ifInOctets.3 = Counter32: 0
        IF-MIB::ifInOctets.4 = Counter32: 0
        IF-MIB::ifInOctets.6 = Counter32: 1619025492
        IF-MIB::ifInOctets.7 = Counter32: 2463331598
        IF-MIB::ifInOctets.8 = Counter32: 3630545960
        IF-MIB::ifInOctets.9 = Counter32: 2570129655
        IF-MIB::ifInOctets.10 = Counter32: 0
        IF-MIB::ifInOctets.11 = Counter32: 2308743436
        IF-MIB::ifInOctets.12 = Counter32: 401489415
        IF-MIB::ifInOctets.13 = Counter32: 0
        IF-MIB::ifInOctets.14 = Counter32: 0
        IF-MIB::ifInOctets.15 = Counter32: 0
        IF-MIB::ifInOctets.16 = Counter32: 1555109398
        IF-MIB::ifInOctets.17 = Counter32: 0
        IF-MIB::ifInOctets.18 = Counter32: 38671
        IF-MIB::ifInOctets.19 = Counter32: 0
        IF-MIB::ifInOctets.20 = Counter32: 0
        IF-MIB::ifInOctets.21 = Counter32: 0
        IF-MIB::ifInOctets.22 = Counter32: 0
        IF-MIB::ifInOctets.23 = Counter32: 0
        IF-MIB::ifInOctets.24 = Counter32: 0
        IF-MIB::ifInOctets.25 = Counter32: 0
        IF-MIB::ifInOctets.26 = Counter32: 3644608740
        IF-MIB::ifInOctets.27 = Counter32: 0
        IF-MIB::ifInOctets.28 = Counter32: 0
        IF-MIB::ifInOctets.29 = Counter32: 2397532255
        IF-MIB::ifInOctets.30 = Counter32: 0
        IF-MIB::ifInOctets.31 = Counter32: 0
        IF-MIB::ifInOctets.32 = Counter32: 0
        IF-MIB::ifInOctets.33 = Counter32: 0
        IF-MIB::ifInOctets.34 = Counter32: 0
        IF-MIB::ifInOctets.35 = Counter32: 0
        IF-MIB::ifInOctets.36 = Counter32: 0
        IF-MIB::ifInOctets.37 = Counter32: 0
        IF-MIB::ifInOctets.38 = Counter32: 0
        IF-MIB::ifInOctets.39 = Counter32: 0
        IF-MIB::ifInOctets.40 = Counter32: 0
        IF-MIB::ifInOctets.41 = Counter32: 0
        IF-MIB::ifInOctets.42 = Counter32: 0
        IF-MIB::ifInOctets.43 = Counter32: 4082357090
        IF-MIB::ifInOctets.44 = Counter32: 1905708319
        IF-MIB::ifInOctets.45 = Counter32: 0
        IF-MIB::ifInOctets.46 = Counter32: 0
        IF-MIB::ifInOctets.47 = Counter32: 0
        IF-MIB::ifInOctets.48 = Counter32: 0
        IF-MIB::ifInOctets.49 = Counter32: 0
        IF-MIB::ifInOctets.50 = Counter32: 0
        IF-MIB::ifInOctets.51 = Counter32: 2710232851
        IF-MIB::ifInOctets.52 = Counter32: 0

从上面可以看到，可以获取到52个接口的信息。那么，这就结束了？当然不是，实际上按照这个接口信息去统计流量信息是不正确的；因为这个交换机只有24个ethernet接口，8个光口，也就是说这个交换机实际的物理接口总共32个。但现在得到的接口却是52个，明显不正确。这种情况下该如何判断使用snmpwalk命令得到的接口相对应的物理接口是哪个？

这个时候可以使用ifDescr进行查看然后与上面的比对就可以知道了，具体用法如下（其中testPublic是community社区名称）：

    [root@localhost ~]# snmpwalk -v 2c -c testPublic 172.16.100.1 ifDescr
    IF-MIB::ifDescr.1 = STRING: InLoopBack0
    IF-MIB::ifDescr.2 = STRING: NULL0
    IF-MIB::ifDescr.3 = STRING: Console9/0/0
    IF-MIB::ifDescr.4 = STRING: MEth0/0/1
    IF-MIB::ifDescr.6 = STRING: GigabitEthernet0/0/1
    IF-MIB::ifDescr.7 = STRING: GigabitEthernet0/0/2
    IF-MIB::ifDescr.8 = STRING: GigabitEthernet0/0/3
    IF-MIB::ifDescr.9 = STRING: GigabitEthernet0/0/4
    IF-MIB::ifDescr.10 = STRING: GigabitEthernet0/0/5
    IF-MIB::ifDescr.11 = STRING: GigabitEthernet0/0/6
    IF-MIB::ifDescr.12 = STRING: GigabitEthernet0/0/7
    IF-MIB::ifDescr.13 = STRING: GigabitEthernet0/0/8
    IF-MIB::ifDescr.14 = STRING: GigabitEthernet0/0/9
    IF-MIB::ifDescr.15 = STRING: GigabitEthernet0/0/10
    IF-MIB::ifDescr.16 = STRING: GigabitEthernet0/0/11
    IF-MIB::ifDescr.17 = STRING: GigabitEthernet0/0/12
    IF-MIB::ifDescr.18 = STRING: GigabitEthernet0/0/13
    IF-MIB::ifDescr.19 = STRING: GigabitEthernet0/0/14
    IF-MIB::ifDescr.20 = STRING: GigabitEthernet0/0/15
    IF-MIB::ifDescr.21 = STRING: GigabitEthernet0/0/16
    IF-MIB::ifDescr.22 = STRING: GigabitEthernet0/0/17
    IF-MIB::ifDescr.23 = STRING: GigabitEthernet0/0/18
    IF-MIB::ifDescr.24 = STRING: GigabitEthernet0/0/19
    IF-MIB::ifDescr.25 = STRING: GigabitEthernet0/0/20
    IF-MIB::ifDescr.26 = STRING: GigabitEthernet0/0/21
    IF-MIB::ifDescr.27 = STRING: GigabitEthernet0/0/22
    IF-MIB::ifDescr.28 = STRING: GigabitEthernet0/0/23
    IF-MIB::ifDescr.29 = STRING: GigabitEthernet0/0/24
    IF-MIB::ifDescr.30 = STRING: GigabitEthernet0/0/25
    IF-MIB::ifDescr.31 = STRING: GigabitEthernet0/0/26
    IF-MIB::ifDescr.32 = STRING: GigabitEthernet0/0/27
    IF-MIB::ifDescr.33 = STRING: GigabitEthernet0/0/28
    IF-MIB::ifDescr.34 = STRING: GigabitEthernet0/0/29
    IF-MIB::ifDescr.35 = STRING: GigabitEthernet0/0/30
    IF-MIB::ifDescr.36 = STRING: GigabitEthernet0/0/31
    IF-MIB::ifDescr.37 = STRING: GigabitEthernet0/0/32
    IF-MIB::ifDescr.38 = STRING: Vlanif10
    IF-MIB::ifDescr.39 = STRING: Vlanif20
    IF-MIB::ifDescr.40 = STRING: Vlanif30
    IF-MIB::ifDescr.41 = STRING: Vlanif40
    IF-MIB::ifDescr.42 = STRING: Vlanif100
    IF-MIB::ifDescr.43 = STRING: Eth-Trunk1
    IF-MIB::ifDescr.44 = STRING: Eth-Trunk2
    IF-MIB::ifDescr.45 = STRING: Vlanif200
    IF-MIB::ifDescr.46 = STRING: Vlanif21
    IF-MIB::ifDescr.47 = STRING: Vlanif22
    IF-MIB::ifDescr.48 = STRING: Vlanif201
    IF-MIB::ifDescr.49 = STRING: Vlanif202
    IF-MIB::ifDescr.50 = STRING: Vlanif23
    IF-MIB::ifDescr.51 = STRING: Eth-Trunk3
    IF-MIB::ifDescr.52 = STRING: Vlanif66

可以看到有32个GigabitEthernet接口，8个光口也显示为GigabitEthernet的原因是这8个光口没有安装光模块，因此暂时显示为GigabitEthernet接口。

参考：http://blog.csdn.net/ysdaniel/article/details/37927541