暗夜星空: May 2019

Sunday, May 26, 2019

Cisco UCS 系列服务器RAID配置手册

Cisco UCS C系列服务器配置手册

重启后在如下图1所示界面时按Ctrl+H进入图2的Raid配置界面。

图1

图2

进入到raid的配置界面，左面导航选择Configuration Wizard，进入图3。

图3

因为第一次做RAID，所以选择New configuration 创建新的raid配置，点击Next，进入图4。

图4

选择Manual Configuration手动安装，然后点击Next进入图5。

图5

将图5左侧的多个硬盘全部加入右侧到Drive Groups中（每选择一个Slot，点击一次Add To Array），全部磁盘移动右侧后，右侧下发会出现一个Accept DG按钮，点击这个按钮，然后点击Next，进入图6。

图6

图6中Array With Free Space下拉框选择刚才创建的device group后，点击左侧Add to SPAN按钮，然后点击Next进入图7。

图7

在图7中RAID Level选择RAID1，Select Size点击右侧的Update会自动将可使用空间计算出来，其他选项保持默认，然后点击Accept，在点击Next。此时弹出是否保持当前配置的画面选择YES，再点击Next进入下一步进入磁盘初始化界面，点击YES完成磁盘初始化操作后，点击Home返回到图2的系统菜单。然后点击Exit让服务器重启。

由于时间悠久，忘及了一台UCS服务器上ESXi 6.5的root密码，试了经常使用的Password还是进不去系统，最终决定重置root 密码。
VMware 官方给出的文档中，ESXi 6.X重置密码只有一种方法，那种是重装ESXi。此做法会删除掉原来系统中的网络配置信息，以及虚拟机的注册信息。
后来查询网络上的还有一种重置密码的方式，并且不会丢任何配置，简直完美。
故决定尝试此方法。

此方法如下：

首先我们要知道如何才能清空或者更改Linux（esxi宿主系统也是基于Linux的）的密码，那就是/etc/shadow文件。下面是一个例子：


[root@server3 ~]# cat /etc/shadow
root:$6$iPXm3umdXcylLJcT$5IGiI4pso/SrkCw3VRqi1lQZDnvtP50REuaN/Q4aXCvcmN7Za4HcCrgjxVRxUxdww8VpMYbj2oPm51ittaPrF/::0:99999:7:::
bin:*:17632:0:99999:7:::
daemon:*:17632:0:99999:7:::
adm:*:17632:0:99999:7:::

我们要做的就是使用第三方系统进入主机，越权操作Esxi宿主机系统的/etc/shadow文件。

在这里我们介绍一下Esxi使用了多个磁盘分区。其中一个比较特别的叫做bootbank。此分区包含管理程序核心文件和主机配置，这最终会被加载到内存中。默认情况下，分区称为/dev/sda5。

我们所关注的/etc/shadow文件位于名为state.tgz的压缩存档中，该存档位于/dev/sda5下。

所以，这就是我们需要做的。

下载Live Linux CD/DVD。从这个列表中选择。我选择了Centos 7。
使用Live CD/DVD刻录USB或CD/DVD，然后启动主机。
挂载/dev/sda5并将state.tgz复制到临时文件夹。
解压缩state.tgz并编辑影子文件。
重新压缩存档并用它覆盖state.tgz
卸载并重新启动主机。

第一步：从Centos 7官网下载相关镜像。保存在本地，然后有两种方法可以使用Centos镜像将Server引导起来，第一种就是平常使用的，将Centos IOS镜像文件使用UltraIOS（中文名叫软碟通）写入的U盘，然后使用U盘引导server启动。此方法适用于所有设备。第二种方法就是比较专业的，真正的Server中才会有的远程管理卡。比如：Dell的叫做iDRAC，CISCO的UCS叫做CIMC（Cisco Integrated Management Controller）等，使用远程管理卡中的JAVA控制台，将IOS虚拟成一个CD来引导系统，此方法对网络要求高，但是不用去现场，比如我这次使用的就是CIMC，server在印度的班加罗尔，但是我在中国大陆。

进入CentOS7系统安装界面

进入救援模式

4、救援模式下，挂载磁盘


mkdir /mnt/sda5
mount /dev/sda5 /mnt/sda5 
cp /mnt/sda5/state.tgz /tmp/.
cd /tmp
tar xvfz state.tgz
tar xvfz local.tgz
vi /tmp/etc/shadow

把类似如下图root开头，键盘上下左右键，把光标移动到第1个冒号后面，按"x"键,把画红线内容给清除掉，

完成后如下图，然后按 "ESC" 输入：wq 回车就保存退出了。不要忽略了冒号（：）此冒号也是命令的一部分。

5、把文件恢复原样，拷回原位


rm -f *.tgz
tar cf local.tgz etc
tar cf state.tgz local.tgz
cp state.tgz /mnt/sda5/.
umount /mnt/sda5
reboot

6. 重启后密码就清空了。

注意在第五步中的重启时需要移除Centos的引导，直接使用ESXi 6.5引导系统即可，等开机后按F2进入输入密码的界面，密码为空直接按回车即可进入ESXi。

Saturday, May 18, 2019

BGP summary

BGP负载均衡

第二条选路原则如果不一致，使用下面的命令可以跳过LocP比较，但是仍然不会负载均衡。
bgp bestpath loc ignore

如果第四条选路原则 AS-Past一样长，但是序列不一致，默认仍然不会负载均衡。
需要使用BGP隐藏命令，才能让BGP负载均衡。
bgp bestpath as-path multipath-relax

BGP eibgp负载命令可以使EBGP和IBGP学来的路由同时进入路由表
maximum-paths eibgp 2

第八条选路IGP metric如果不一致，可以使用以下命令跳过比较，BGP仍然可以负载均衡。
bgp bestpath igp-metric ignore

Tuesday, May 7, 2019

Linux 解压命令

Linux下常见的压缩包格式有5种:zip tar.gz tar.bz2 tar.xz tar.Z

其中tar是种打包格式,gz和bz2等后缀才是指代压缩方式:gzip和bzip2

filename.zip的解压:

unzip filename.zip

filename.tar.gz的解压:

tar -zxvf filename.tar.gz

其中zxvf含义分别如下

z: 　　gzip 　　　　　　　　压缩格式

x: 　　extract　　　　　　　　解压

v:　　 verbose　　　　　　　　详细信息

f: 　　file(file=archieve)　　　　文件

filename.tar.bz2的解压:

tar -jxvf filename.tar.bz2

j: 　　bzip2　　　　　　　　　压缩格式

其它选项和tar.gz解压含义相同

filename.tar.xz的解压:

tar -Jxvf filename.tar.xz

注意J大写

filename.tar.Z的解压:

tar -Zxvf filename.tar.Z

注意Z大写

关于tar的详细命令可以

tar --help

事实上, 从1.15版本开始tar就可以自动识别压缩的格式,故不需人为区分压缩格式就能正确解压

tar -xvf filename.tar.gz
tar -xvf filename.tar.bz2
tar -xvf filename.tar.xz
tar -xvf filename.tar.Z

Linux下tar命令解压到指定的目录：

tar -zxvf /bbs.tar.zip -C /zzz/bbs    
1

//把根目录下的bbs.tar.zip解压到/zzz/bbs下，前提要保证存在/zzz/bbs这个目录
这个和cp命令有点不同，cp命令如果不存在这个目录就会自动创建这个目录！

附：用tar命令打包
例：将当前目录下的zzz文件打包到根目录下并命名为zzz.tar.gz

tar zcvf /zzz.tar.gz ./zzz
1

tar 解压缩命令
tar
-c: 建立压缩档案
-x：解压
-t：查看内容
-r：向压缩归档文件末尾追加文件
-u：更新原压缩包中的文件
这五个是独立的命令，压缩解压都要用到其中一个，可以和别的命令连用但只能用其中一个。下面的参数是根据需要在压缩或解压档案时可选的。
-z：有gzip属性的
-j：有bz2属性的
-Z：有compress属性的
-v：显示所有过程
-O：将文件解开到标准输出
下面的参数-f是必须的
-f: 使用档案名字，切记，这个参数是最后一个参数，后面只能接档案名。

tar -cf all.tar *.jpg
1

这条命令是将所有.jpg的文件打成一个名为all.tar的包。-c是表示产生新的包，-f指定包的文件名。

tar -rf all.tar *.gif
1

这条命令是将所有.gif的文件增加到all.tar的包里面去。-r是表示增加文件的意思。

tar -uf all.tar logo.gif
1

这条命令是更新原来tar包all.tar中logo.gif文件，-u是表示更新文件的意思。

tar -tf all.tar
1

这条命令是列出all.tar包中所有文件，-t是列出文件的意思

tar -xf all.tar
1

这条命令是解出all.tar包中所有文件，-x是解开的意思

压缩

tar –cvf jpg.tar *.jpg //将目录里所有jpg文件打包成tar.jpg

tar –czf jpg.tar.gz *.jpg //将目录里所有jpg文件打包成jpg.tar后，并且将其用gzip压缩，生成一个gzip压缩过的包，命名为jpg.tar.gz

tar –cjf jpg.tar.bz2 *.jpg //将目录里所有jpg文件打包成jpg.tar后，并且将其用bzip2压缩，生成一个bzip2压缩过的包，命名为jpg.tar.bz2

tar –cZf jpg.tar.Z *.jpg //将目录里所有jpg文件打包成jpg.tar后，并且将其用compress压缩，生成一个umcompress压缩过的包，命名为jpg.tar.Z

rar a jpg.rar *.jpg //rar格式的压缩，需要先下载rar for linux

zip jpg.zip *.jpg //zip格式的压缩，需要先下载zip for linux
解压

tar –xvf file.tar //解压 tar包

tar -xzvf file.tar.gz //解压tar.gz

tar -xjvf file.tar.bz2 //解压 tar.bz2

tar –xZvf file.tar.Z //解压tar.Z
unrar e file.rar //解压rar
unzip file.zip //解压zip

总结

1、*.tar 用 tar –xvf 解压
2、*.gz 用 gzip -d或者gunzip 解压
3、.tar.gz和.tgz 用 tar –xzf 解压
4、*.bz2 用 bzip2 -d或者用bunzip2 解压
5、*.tar.bz2用tar –xjf 解压
6、*.Z 用 uncompress 解压
7、*.tar.Z 用tar –xZf 解压
8、*.rar 用 unrar e解压
9、*.zip 用 unzip 解压

CISCO SNMP计数器

SNMP计数器问题

问：我应该将哪个MIB用于接口计数器？

A.基于SNMP的接口管理基于两个表：ifTable（仅限注册用户）及其扩展名，ifxtable（仅限注册用户）在RFC1213 / RFC2233中描述。接口可以有多个层，这取决于介质，每个子层由表中的一个单独的行表示。ifStackTable（仅限注册用户）中描述了较高层和较低层之间的关系。ifTable为入站和出站八位字节定义32位计数器（ifInOctets（仅限注册用户）/ ifOutOctets），数据包（ ifInUcastPkts（仅限注册用户）/ ifOutUcastPkts（仅限注册用户），ifInNUcastPkts（仅限注册用户）/ ifOutNUcastPkts（仅限注册用户）），错误和丢弃。ifXTable提供类似的64位计数器，也称为高容量（HC）计数器：ifHCInOctets（仅限注册用户）/ ifHCOutOctets（仅限注册用户）和ifHCInUcastPkts（已注册）仅限客户）/ ifHCOutUcastPkts（仅限注册用户）。

问：什么时候应该使用64位计数器？

答：RFC 2233采用扩展的64位计数器用于高容量接口，其中32位计数器不能提供足够的容量并且包装速度太快。

随着网络媒体速度的增加，32位计数器包装的最小时间减少。例如，一个10 Mbps的背对背全尺寸数据包流导致ifInOctets在57分钟内完成包装。在100 Mbps时，最小环绕时间为5.7分钟，在1 Gbps时，最小环绕时间为34秒。

注意： SNMP计数器换行，命令行界面（CLI）计数器不换行。

对于以每秒20,000,000（2000万）位或更少的速度运行的接口，必须使用32位字节和数据包计数器。对于运行速度超过每秒2000万比特且速度低于每秒650,000,000比特的接口，必须使用32位数据包计数器和64位八位字节计数器。对于以650,000,000位/秒或更快速运行的接口，必须使用64位数据包和八位字节计数器。

相应地，CiscoIOS®软件不支持64位计数器，接口速度低于20 Mbps。这意味着10 Mb以太网端口不支持64位计数器，只有100 Mb快速以太网和其他高速端口支持64位计数器。

问：查询64位计数器需要哪个版本的SNMP？

A.查询64位计数器需要SNMPv2C或SNMPv3。SNMPv1不支持64位计数器。请注意，ifInOctets = .1.3.6.1.2.1.2.2.1.10是32位计数器，而64位版本是ifHCInOctets = .1.3.6.1.2.1.31.1.1.1.6。

例如：

Catalyst 5000使用HP OpenView snmpget，默认为SNMPv1
#snmpget -c public 14.32.5.18 ifName.1


ifMIB.ifMIBObjects.ifXTable.ifXEntry.ifName.1 DISPLAY STRING-（ascii）sc0
使用SNMPv1查询，HP OpenView snmpget的默认值
#snmpget -c public 14.32.5.18 ifHCInOctets.1


snmpget代理报告了变量＃1的错误。 
.iso.org.dod.internet.mgmt.mib-2.ifMIB.ifMIBObjects.ifXTable.ifXEntry。
   ifHCInOctets.1


SNMP变量不存在或访问被拒绝。 
与SNMPv2C相同的查询
#snmpget -v 2c -c public 14.32.5.18 ifHCInOctets.1


ifMIB.ifMIBObjects.ifXTable.ifXEntry.ifHCInOctets.1 Counter64 622366215 

问：哪些Cisco设备实现64位SNMP计数器，尤其是IF-MIB？

答：这些思科设备实现了64位SNMP计数器：

注意：您必须是注册用户，并且您必须登录才能访问Cisco Bug ID链接并查看详细的错误信息。

Cisco 2500,2600路由器 - 这些路由器不支持64位计数器。

Catalyst 2950和3550-Support始于Cisco IOS软件版本12.1（11）EA1，因为Cisco Bug ID CSCdx67611（仅限注册用户）和Cisco Bug ID CSCdw52807（仅限注册用户）。

Catalyst 2900XL和3500XL-Support始于Cisco IOS软件版本12.0（5）WC3，因为Cisco Bug ID CSCds45300（仅限注册用户）。

Catalyst 5000系列 - 自Cisco IOS软件版本3.x. 在RSM / RSFC上，支持从Cisco IOS软件版本12.1（6）E1开始，因为Cisco Bug ID CSCds50549（仅限注册用户）。

Catalyst 5000/6000 ATM模块 - 自Cisco IOS软件版本12.0（14）W05（20）以来，请参阅Cisco Bug ID CSCds07238（仅限注册用户）。

Catalyst 6000千兆以太网WAN OSM - 自Cisco IOS软件版本12.1.12E以来，请参阅Cisco Bug ID CSCdw64849（仅限注册用户）。

Catalyst 6000系列 - 所有Cisco IOS软件版本。WS-F6K-MSFC和MSM支持从Cisco IOS软件版本12.1（8a）E4开始。

Catalyst 8500系列 - 支持从Cisco IOS软件版本12.0（5）W5（13）开始。

Cisco路由器3600,4000和更高平台 - 从Cisco IOS软件12.0（1）和Cisco IOS软件版本12.0（1）T开始，请参阅Cisco Bug ID CSCdj93712（仅限注册用户）和Cisco Bug ID CSCdt58029（仅限注册用户））。

帧中继接口 - 从Cisco IOS软件版本12.0（17）S和Cisco IOS软件版本12.2（4）T3开始，请参考帧中继64位计数器。

OC3 ATM接口 - 从Cisco IOS软件版本12.0（6）T开始，请参阅Cisco Bug ID CSCdm45357（仅限注册用户）。

隧道接口 - 从Cisco IOS软件版本12.0（16）S开始，请参阅Cisco Bug ID CSCdt58029（仅限注册用户）。

注意： Cisco IOS软件不支持64位计数器，接口速度低于20 Mbps。这意味着10 Mb以太网端口不支持64位计数器。只有100 Mb快速以太网和其他高速端口支持64位计数器。

问：ifInOctets和ifOutOctets SNMP计数器是否与show interface In / Out计数器相同？

答：是的，但仅在启动时启用SNMP时。如果启动Cisco设备，然后启用SNMP，则SNMP计数器从0开始。它们不会自动从CLI输出中获取其值。

问：ifInOctets和ifOutOctets计数器是否包括成帧开销（点对点协议，高级数据链路控制）？

答：是的。

问：在异步传输模式接口上，计数器是否包含单元头？

A.异步传输模式（ATM）计数器不包括ATM开销（信元标头和AAL5填充）。

问：为什么SNMP计数器不会返回与CLI show命令相同的数字？

A.定义为计数器的SNMP对象必须遵守RFC1155 ：

“3.2.3.3。反击

这个应用程序范围的类型表示一个非负整数，当它环绕并从零开始再次增加时，它会单调增加直到达到最大值。此备忘录指定计数器的最大值为2 ^ 32-1（小数为4294967295）。“

没有重新加载设备的方法，无法将SNMP计数器重置为零。

CLI show命令的计数器输出可以在接口上重置，因为SNMP限制不存在。

MIB-2中定义的原始接口计数器是32位计数器。对于10 Mbps接口，32位计数器理论上可以在57分钟内完成。很容易避免这么长时间的不连续性。但对于100 Mbps，最小理论包装时间为5.7分钟。对于1 Gbps接口，它降至34秒。这些时间用于传输背对背的全尺寸数据包，这是理论上的理想选择。即便如此，界面速度越高，越难以避免错过反包装。作为此问题的解决方案，SNMPv2 SMI为64位计数器定义了一个新的对象类型counter64。因此，在RFC 1573中定义的扩展接口表（ifxTable）中定义了几个新的64位计数器（后来被RFC 2233取代））。这些来自IF-MIB-V1SMI.my（仅限注册用户）。

ifHCInOctets （.1.3.6.1.2.1.31.1.1.1.6） ifHCOutOctets （1.3.6.1.2.1.31.1.1.1.10）

ifHCInUcastPkts （.1.3.6.1.2.1.31.1.1.1.7） ifHCOutUcastPkts （.1.3.6.1.2.1.31.1.1.1.11）

ifHCInMulticastPkts （.1.3.6.1.2.1.31.1.1.1.8） ifHCOutMulticastPkts （.1.3.6.1.2.1.31.1.1.1.12）

ifHCInBroadcastPkts （.1.3.6.1.2.1.31.1.1.1.9） ifHCOutBroadcastPkts （.1.3.6.1.2.1.31.1.1.1.13）

虽然64位计数器的基本支持已写入Cisco IOS软件版本11.3，该版本从Cisco IOS软件版本12.0开始，但仅限于HCInOctets（.1.3.6.1.2.1.31.1.1.1.6）和ifHCOutOctets（1.3.6.1.2.1） .31.1.1.1.10）仅针对ATM LANE LEC子接口实现。对于Catalyst工作组交换机，版本3.1中已实现64位计数器支持。

注意：必须使用SNMPv2c或SNMPv3协议才能检索任何计数器64对象。

SNMP计数器和show命令等效问题

问：Cisco路由器为以下SNMP MIB变量做了什么：ifInOctets，ifInUcastPkts，ifInNUcastPkts，ifInDiscards，ifInErrors，ifInUnknownProtos，ifOutOctets，ifOutUcastPkts，ifOutNUcastPkts，ifOutDiscards，ifOutErrors和ifOutQLen？

A.有关详细信息，请参阅此表。这些来自RFC1213-MIB（仅限注册用户）。

ifInNUcastPkts（.1.3.6.1.2.1.2.2.1.12）这些是入站广播和多播数据包的计数。

ifInDiscards（.1.3.6.1.2.1.2.2.1.13）这些被视为无缓冲区，如show interfaces命令中所反映的那样。

ifInErrors（.1.3.6.1.2.1.2.2.1.14）这些是show interfaces命令中反映的所有输入错误的计数。

ifInUnknownProtos（.1.3.6.1.2.1.2.2.1.15）这些被视为未分类的错误。

ifOutOctets（.1.3.6.1.2.1.2.2.1.16）这些是接口输出的字节数的计数，如show interfaces命令所示。

ifOutUcastPkts（.1.3.6.1.2.1.2.2.1.17）这些是出站广播和多播数据包的计数。

ifOutDiscards（.1.3.6.1.2.1.2.2.1.19）这些被计为输出丢弃，如show interfaces命令所示。

ifOutErrors（.1.3.6.1.2.1.2.2.1.20）这些被计为输出错误，如show interfaces命令中所示。

ifOutQLen（.1.3.6.1.2.1.2.2.1.21）这是允许在输出队列上的数据包数，如show interfaces命令所示。

之前列出的不显示它们出现在show interfaces中的变量在除SNMP之外的任何地方都不可用。

例子

此示例使用与Cisco IOS软件版本12.2（2）T1一起运行的3640。使用的只读（RO）团体字符串是公共的，并且使用的读写（RW）团体字符串是私有的。有关如何在设备上配置SNMP社区字符串的详细信息，请参阅如何配置SNMP社区字符串。

此输出是启用模式下执行的show ip interface brief命令的典型输出：

3600#show ip interface brief 
Interface    IP-Address      OK? Method Status  Prol 
BRI0/0       unassigned      YES NVRAM  administratively down dow 
FastEthernet0/0     172.16.99.20    YES NVRAM  up      up 
Serial0/0    unassigned      YES NVRAM  down    dow 
Serial0/0.1  unassigned      YES unset  down    dow 
BRI0/0:1     unassigned      YES unset  administratively down dow 
BRI0/0:2     unassigned      YES unset  administratively down dow 
Serial0/1    unassigned      YES NVRAM  administratively down dow 
ATM1/0       unassigned      YES NVRAM  down    dow 
ATM1/0.109   10.164.0.46     YES NVRAM  down    dow 
Virtual-Template1   99.99.99.99     YES NVRAM  down    dow 
Loopback0    10.1.10.1       YES NVRAM  up      up 
Loopback1    unassigned      YES NVRAM  up      up 
Loopback101  3.3.3.3  YES NVRAM  administratively down dow 
Loopback200  4.4.4.14 YES NVRAM  administratively down dow

Loopback201 4.4.4.18 YES NVRAM administratively down dow

此输出是前一个路由器的描述（.1.3.6.1.2.1.2.2.1.2）的MIB对象，它是包含接口信息的文本字符串。这给出了获得的接口名称和描述，它使用以前的CLI命令输出。IFNAME（.1.3.6.1.2.1.31.1.1.1.1）也可以使用，但ifDescr给出的名称，其中，沿所述接口描述IFNAME只给出了接口名。

snmpwalk 172.16.99.20 public .1.3.6.1.2.1.2.2.1.2 
interfaces.ifTable.ifEntry.ifDescr.1 = ATM1/0 
interfaces.ifTable.ifEntry.ifDescr.2 = BRI0/0 
interfaces.ifTable.ifEntry.ifDescr.3 = FastEthernet0/0 
interfaces.ifTable.ifEntry.ifDescr.4 = Serial0/0 
interfaces.ifTable.ifEntry.ifDescr.5 = BRI0/0:1 
interfaces.ifTable.ifEntry.ifDescr.6 = BRI0/0:2 
interfaces.ifTable.ifEntry.ifDescr.7 = Serial0/1 
interfaces.ifTable.ifEntry.ifDescr.8 = Null0 
interfaces.ifTable.ifEntry.ifDescr.10 = Foreign Exchange Office 2/0/0 
interfaces.ifTable.ifEntry.ifDescr.11 = Foreign Exchange Office 2/0/1 
interfaces.ifTable.ifEntry.ifDescr.12 = recEive And transMit 3/0/0 
interfaces.ifTable.ifEntry.ifDescr.13 = recEive And transMit 3/0/1 
interfaces.ifTable.ifEntry.ifDescr.14 = Loopback0 
interfaces.ifTable.ifEntry.ifDescr.15 = Loopback1 
interfaces.ifTable.ifEntry.ifDescr.16 = Loopback101 
interfaces.ifTable.ifEntry.ifDescr.17 = Loopback200 
interfaces.ifTable.ifEntry.ifDescr.18 = Loopback201 
interfaces.ifTable.ifEntry.ifDescr.19 = Serial0/0.1 
interfaces.ifTable.ifEntry.ifDescr.20 = ATM1/0.109-atm subif 
interfaces.ifTable.ifEntry.ifDescr.21 = ATM1/0.109-aal5 layer 
interfaces.ifTable.ifEntry.ifDescr.22 = Virtual-Template1 
interfaces.ifTable.ifEntry.ifDescr.23 = Voice Encapsulation (POTS) Peer: 1 
interfaces.ifTable.ifEntry.ifDescr.24 = Voice Over IP Peer: 2 
interfaces.ifTable.ifEntry.ifDescr.25 = Voice Encapsulation (POTS) Peer: 111 
interfaces.ifTable.ifEntry.ifDescr.26 = Voice Over IP Peer: 222 
interfaces.ifTable.ifEntry.ifDescr.27 = Voice Over IP Peer: 1234 
interfaces.ifTable.ifEntry.ifDescr.28 = Voice Over IP Peer: 300000 
interfaces.ifTable.ifEntry.ifDescr.29 = Voice Over FR Peer: 3 
interfaces.ifTable.ifEntry.ifDescr.30 = Voice Over IP Peer: 99 
interfaces.ifTable.ifEntry.ifDescr.31 = Voice Encapsulation (POTS) Peer: 9 
interfaces.ifTable.ifEntry.ifDescr.32 = BRI0/0-Physical 
interfaces.ifTable.ifEntry.ifDescr.33 = BRI0/0-Signaling 
interfaces.ifTable.ifEntry.ifDescr.34 = BRI0/0:1-Bearer Channel 
interfaces.ifTable.ifEntry.ifDescr.35 = BRI0/0:2-Bearer Channel

ifInDiscards (.1.3.6.1.2.1.2.2.1.13):

snmpwalk 172.16.99.20 public .1.3.6.1.2.1.2.2.1.13 

interfaces.ifTable.ifEntry.ifInDiscards.1 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.2 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.3 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.4 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.5 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.6 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.7 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.8 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.10 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.11 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.12 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.13 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.14 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.15 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.16 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.17 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.18 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.19 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.20 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.21 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.22 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.23 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.24 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.25 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.26 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.27 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.28 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.29 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.30 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.31 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.32 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.33 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.34 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInDiscards.35 = Counter32: 0

该ifInDiscards是该路由器的所有接口零。如果将此与show interfaces fastEthernet 0/0命令的CLI结果进行比较，则会确认结果：

3600#show interfaces fastEthernet 0/0 
FastEthernet0/0 is up, line protocol is up 
  Hardware is AmdFE, address is 0001.42b4.fe81 (bia 0001.42b4.fe81) 
  Description: testme 
  Internet address is 172.16.99.20/24 
  MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec, 
     reliability 255/255, txload 1/255, rxload 1/255 
  Encapsulation ARPA, loopback not set 
  Keepalive set (10 sec) 
  Full-duplex, 100Mb/s, 100BaseTX/FX 
  ARP type: ARPA, ARP Timeout 04:00:00 
  Last input 00:00:00, output 00:00:00, output hang never 
  Last clearing of "show interface" counters never 
  Queueing strategy: fifo 
  Output queue 0/40, 0 drops; input queue 0/75, 323 drops 
  5 minute input rate 1000 bits/sec, 2 packets/sec 
  5 minute output rate 0 bits/sec, 0 packets/sec 
     1767411 packets input, 178272010 bytes 
     Received 1161500 broadcasts, 0 runts, 0 giants, 0 throttles 
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored 
     0 watchdog 
     0 input packets with dribble condition detected 
7146925 packets output, 765049281 bytes, 0 underruns(0/0/0) 
     0 output errors, 0 collisions, 1 interface resets 
     0 babbles, 0 late collision, 461 deferred 
     0 lost carrier, 0 no carrier 
     0 output buffer failures, 0 output buffers swapped out

ifInErrors (.1.3.6.1.2.1.2.2.1.14):

snmpwalk 172.16.99.20 public .1.3.6.1.2.1.2.2.1.14 

interfaces.ifTable.ifEntry.ifInErrors.1 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInErrors.2 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInErrors.3 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInErrors.4 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInErrors.5 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInErrors.6 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInErrors.7 = Counter32: 1 
interfaces.ifTable.ifEntry.ifInErrors.8 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInErrors.10 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInErrors.11 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInErrors.12 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInErrors.13 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInErrors.14 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInErrors.15 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInErrors.16 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInErrors.17 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInErrors.18 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInErrors.19 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInErrors.20 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInErrors.21 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInErrors.22 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInErrors.23 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInErrors.24 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInErrors.25 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInErrors.26 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInErrors.27 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInErrors.28 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInErrors.29 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInErrors.30 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInErrors.31 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInErrors.32 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInErrors.33 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInErrors.34 = Counter32: 0 
interfaces.ifTable.ifEntry.ifInErrors.35 = Counter32: 0

此输出显示接口只有一个输入错误

interfaces.ifTable.ifEntry.ifInErrors.7 = Counter32：1。

为了确定它是哪个接口，将其与上面ifDescr的输出进行比较，这表明它来自interfaces.ifTable.ifEntry.ifDescr.7 = Serial0 / 1。现在在启用模式下执行show interfaces serial 0/1命令以验证以前的结果：

3600#show interfaces serial 0/1 
Serial0/1 is administratively down, line protocol is down 
  Hardware is DSCC4 Serial 
  Description: atm-dxi test 
  MTU 1500 bytes, BW 2048 Kbit, DLY 20000 usec, 
     reliability 255/255, txload 1/255, rxload 1/255 
  Encapsulation ATM-DXI, loopback not set 
  Keepalive not set 
  Last input never, output never, output hang never 
  Last clearing of "show interface" counters 1w1d 
  Queueing strategy: fifo 
  Output queue 0/40, 0 drops; input queue 0/75, 0 drops 
  5 minute input rate 0 bits/sec, 0 packets/sec 
  5 minute output rate 0 bits/sec, 0 packets/sec 
     0 packets input, 0 bytes, 0 no buffer 
     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles 
     1 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 1 abort 
     0 packets output, 0 bytes, 0 underruns 
     0 output errors, 0 collisions, 0 interface resets 
     0 output buffer failures, 0 output buffers swapped out 
     0 carrier transitions 
     DCD=down  DSR=down  DTR=down  RTS=down  CTS=down

ifOutOctets (.1.3.6.1.2.1.2.2.1.16):

snmpwalk 172.16.99.20 public .1.3.6.1.2.1.2.2.1.16 

interfaces.ifTable.ifEntry.ifOutOctets.1 = Counter32: 98 
interfaces.ifTable.ifEntry.ifOutOctets.2 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutOctets.3 = Counter32: 765470674 
interfaces.ifTable.ifEntry.ifOutOctets.4 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutOctets.5 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutOctets.6 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutOctets.7 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutOctets.8 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutOctets.10 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutOctets.11 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutOctets.12 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutOctets.13 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutOctets.14 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutOctets.15 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutOctets.16 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutOctets.17 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutOctets.18 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutOctets.19 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutOctets.20 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutOctets.21 = Counter32: 98 
interfaces.ifTable.ifEntry.ifOutOctets.22 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutOctets.23 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutOctets.24 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutOctets.25 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutOctets.26 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutOctets.27 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutOctets.28 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutOctets.29 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutOctets.30 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutOctets.31 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutOctets.32 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutOctets.33 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutOctets.34 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutOctets.35 = Counter32: 0

如果将先前的结果与ifDescr的输出进行比较，则表明：

interfaces.ifTable.ifEntry.ifOutOctets.1 = Counter32：98对应interfaces.ifTable.ifEntry.ifDescr.1 = ATM1 / 0
interfaces.ifTable.ifEntry.ifOutOctets.3 = Counter32：765470674对应interfaces.ifTable.ifEntry.ifDescr.3 = FastEthernet0 / 0
interfaces.ifTable.ifEntry.ifOutOctets.21 = Counter32：98对应interfaces.ifTable.ifEntry.ifDescr.21 = ATM1 / 0.109-aal5 layer

这是在启用模式下执行的每个先前接口的CLI show interfaces命令的输出：

3600#show interfaces atM 1/0 
   ATM1/0 is down, line protocol is down 
  Hardware is RS8234 ATMOC3 
  MTU 4470 bytes, sub MTU 4470, BW 155000 Kbit, DLY 80 usec, 
     reliability 5/255, txload 1/255, rxload 1/255 
  Encapsulation ATM, loopback not set 
  Encapsulation(s): AAL5 
  1024 maximum active VCs, 1 current VCCs 
  VC idle disconnect time: 300 seconds 
  Last input never, output 1w1d, output hang never 
  Last clearing of "show interface" counters never 
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 
  Queueing strategy: None 
  5 minute input rate 0 bits/sec, 0 packets/sec 
  5 minute output rate 0 bits/sec, 0 packets/sec 
     0 packets input, 0 bytes, 0 no buffer 
     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles 
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 
     2 packets output, 98 bytes, 0 underruns 
     0 output errors, 0 collisions, 2 interface resets 
     0 output buffer failures, 0 output buffers swapped out 
  
3600#show interfaces fastEthernet 0/0 
FastEthernet0/0 is up, line protocol is up 
  Hardware is AmdFE, address is 0001.42b4.fe81 (bia 0001.42b4.fe81) 
  Description: testme 
  Internet address is 172.16.99.20/24 
  MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec, 
     reliability 255/255, txload 1/255, rxload 1/255 
  Encapsulation ARPA, loopback not set 
  Keepalive set (10 sec) 
  Full-duplex, 100Mb/s, 100BaseTX/FX 
  ARP type: ARPA, ARP Timeout 04:00:00 
  Last input 00:00:00, output 00:00:00, output hang never 
  Last clearing of "show interface" counters never 
  Queueing strategy: fifo 
  Output queue 0/40, 0 drops; input queue 0/75, 323 drops 
  5 minute input rate 2000 bits/sec, 3 packets/sec 
  5 minute output rate 1000 bits/sec, 1 packets/sec 
     1772214 packets input, 178767841 bytes 
     Received 1164210 broadcasts, 0 runts, 0 giants, 0 throttles 
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored 
0 watchdog 
     0 input packets with dribble condition detected 
     7149179 packets output, 765450524 bytes, 0 underruns(0/0/0) 
     0 output errors, 0 collisions, 1 interface resets 
     0 babbles, 0 late collision, 461 deferred 
     0 lost carrier, 0 no carrier

0 output buffer failures, 0 output buffers swapped out

在输出ifOutOctets不匹配的CLI的输出显示接口，快速以太网0/0命令，却是相似的。这是因为轮询接口和执行CLI命令时可能会有延迟。

3600#show interfaces atM 1/0.109 
ATM1/0.109 is down, line protocol is down 
  Hardware is RS8234 ATMOC3 
  Description: pvc 
  Internet address is 10.164.0.46/30 
  MTU 4470 bytes, BW 2250 Kbit, DLY 80 usec, 
     reliability 5/255, txload 1/255, rxload 1/255 
  Encapsulation ATM 
  0 packets input, 0 bytes 
  2 packets output,98 bytes 
  0 OAM cells input, 77093 OAM cells output 
  AAL5 CRC errors : 0 
  AAL5 SAR Timeouts : 0 
  AAL5 Oversized SDUs : 0 
  AAL5 length violation : 0 
  AAL5 CPI Error : 0

ifOutDiscards (.1.3.6.1.2.1.2.2.1.19):

snmpwalk 172.16.99.20 public .1.3.6.1.2.1.2.2.1.19 

interfaces.ifTable.ifEntry.ifOutDiscards.1 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.2 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.3 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.4 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.5 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.6 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.7 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.8 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.10 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.11 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.12 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.13 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.14 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.15 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.16 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.17 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.18 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.19 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.20 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.21 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.22 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.23 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.24 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.25 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.26 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.27 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.28 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.29 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.30 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.31 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.32 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.33 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.34 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutDiscards.35 = Counter32: 0

所有接口的ifOutDiscards为零。以show interfaces fastEthernet 0/0命令为例，该命令产生以下结果：

3600#show interfaces fastEthernet 0/0 
FastEthernet0/0 is up, line protocol is up 
  Hardware is AmdFE, address is 0001.42b4.fe81 (bia 0001.42b4.fe81) 
  Description: testme 
  Internet address is 172.16.99.20/24 
  MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec, 
     reliability 255/255, txload 1/255, rxload 1/255 
  Encapsulation ARPA, loopback not set 
  Keepalive set (10 sec) 
  Full-duplex, 100Mb/s, 100BaseTX/FX 
  ARP type: ARPA, ARP Timeout 04:00:00 
  Last input 00:00:00, output 00:00:00, output hang never 
  Last clearing of "show interface" counters never 
  Queueing strategy: fifo 
  Output queue 0/40, 0 drops; input queue 0/75, 323 drops 
  5 minute input rate 1000 bits/sec, 2 packets/sec 
  5 minute output rate 1000 bits/sec, 1 packets/sec 
     1774581 packets input, 179005552 bytes 
     Received 1165620 broadcasts, 0 runts, 0 giants, 0 throttles 
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored 
     0 watchdog 
     0 input packets with dribble condition detected 
     7150259 packets output, 765645035 bytes, 0 underruns(0/0/0) 
     0 output errors, 0 collisions, 1 interface resets 
     0 babbles, 0 late collision, 461 deferred 
     0 lost carrier, 0 no carrier 
     0 output buffer failures, 0 output buffers swapped out

ifOutErrors (.1.3.6.1.2.1.2.2.1.20):

snmpwalk 172.16.99.20 public .1.3.6.1.2.1.2.2.1.20

interfaces.ifTable.ifEntry.ifOutErrors.1 = Counter32: 0 interfaces.ifTable.ifEntry.ifOutErrors.2 = Counter32: 0

interfaces.ifTable.ifEntry.ifOutErrors.3 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutErrors.4 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutErrors.5 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutErrors.6 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutErrors.7 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutErrors.8 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutErrors.10 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutErrors.11 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutErrors.12 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutErrors.13 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutErrors.14 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutErrors.15 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutErrors.16 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutErrors.17 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutErrors.18 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutErrors.19 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutErrors.20 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutErrors.21 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutErrors.22 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutErrors.23 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutErrors.24 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutErrors.25 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutErrors.26 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutErrors.27 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutErrors.28 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutErrors.29 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutErrors.30 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutErrors.31 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutErrors.32 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutErrors.33 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutErrors.34 = Counter32: 0 
interfaces.ifTable.ifEntry.ifOutErrors.35 = Counter32: 0

所有接口的ifOutErrors均为零。以show interfaces fastEthernet 0/0命令为例，该命令产生以下结果：

3600#show interfaces fastEthernet 0/0 
FastEthernet0/0 is up, line protocol is up 
  Hardware is AmdFE, address is 0001.42b4.fe81 (bia 0001.42b4.fe81) 
  Description: testme 
  Internet address is 172.16.99.20/24 
  MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec, 
     reliability 255/255, txload 1/255, rxload 1/255 
  Encapsulation ARPA, loopback not set 
  Keepalive set (10 sec) 
  Full-duplex, 100Mb/s, 100BaseTX/FX 
  ARP type: ARPA, ARP Timeout 04:00:00 
  Last input 00:00:00, output 00:00:00, output hang never 
  Last clearing of "show interface" counters never 
  Queueing strategy: fifo 
  Output queue 0/40, 0 drops; input queue 0/75, 323 drops 
  5 minute input rate 0 bits/sec, 1 packets/sec 
  5 minute output rate 0 bits/sec, 0 packets/sec 
     1776187 packets input, 179154616 bytes 
     Received 1166778 broadcasts, 0 runts, 0 giants, 0 throttles 
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored 
     0 watchdog 
     0 input packets with dribble condition detected 
     7150781 packets output, 765744231 bytes, 0 underruns(0/0/0) 
     0 output errors, 0 collisions, 1 interface resets 
     0 babbles, 0 late collision, 461 deferred 
     0 lost carrier, 0 no carrier 
     0 output buffer failures, 0 output buffers swapped out

ifOutQLen (.1.3.6.1.2.1.2.2.1.21):

snmpwalk 172.16.99.20 public .1.3.6.1.2.1.2.2.1.21 

interfaces.ifTable.ifEntry.ifOutQLen.1 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.2 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.3 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.4 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.5 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.6 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.7 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.8 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.10 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.11 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.12 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.13 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.14 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.15 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.16 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.17 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.18 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.19 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.20 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.21 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.22 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.23 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.24 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.25 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.26 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.27 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.28 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.29 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.30 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.31 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.32 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.33 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.34 = Gauge32: 0 
interfaces.ifTable.ifEntry.ifOutQLen.35 = Gauge32: 0

所有接口的ifOutQLen都为零。以show interfaces fastEthernet 0/0命令为例：

3600#show interfaces fastEthernet 0/0 
   FastEthernet0/0 is up, line protocol is up 
     Hardware is AmdFE, address is 0001.42b4.fe81 (bia 0001.42b4.fe81) 
     Description: testme 
     Internet address is 172.16.99.20/24 
     MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec, 
        reliability 255/255, txload 1/255, rxload 1/255 
     Encapsulation ARPA, loopback not set 
     Keepalive set (10 sec) 
     Full-duplex, 100Mb/s, 100BaseTX/FX 
     ARP type: ARPA, ARP Timeout 04:00:00 
     Last input 00:00:00, output 00:00:00, output hang never 
     Last clearing of "show interface" counters never 
     Queueing strategy: fifo 
     Output queue 0/40, 0 drops; input queue 0/75, 323 drops    
     5 minute input rate 0 bits/sec, 1 packets/sec 
     5 minute output rate 0 bits/sec, 0 packets/sec 
        1776912 packets input, 179225431 bytes 
        Received 1167240 broadcasts, 0 runts, 0 giants, 0 throttles    
        0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored    
        0 watchdog 
        0 input packets with dribble condition detected 
        7151102 packets output, 765796341 bytes, 0 underruns(0/0/0)    
        0 output errors, 0 collisions, 1 interface resets 
        0 babbles, 0 late collision, 461 deferred 
        0 lost carrier, 0 no carrier 
        0 output buffer failures, 0 output buffers swapped out


问：show interfaces语句没有缓冲区和输入队列丢弃之间的关系是什么？为什么SNMP的inDiscards 没有缓冲计数而没有输入队列丢弃，而SNMP的outDiscards确实给输出队列丢弃了？




A.该locIfInputQueueDrops / ifInDiscards比locIfOutputQueueDrops / ifOutDiscards工作方式不同。ifInDiscards计算因缺少系统资源（如缓冲区）而丢弃的数据包数。这通常是locIfInputQueueDrops的一个子集。您经常会看到locIfInputQueueDrops = ifInDiscards。但是，locIfInputQueueDrops还会计算因为达到输入队列限制而丢弃的数据包数。通常，您会看到locIfInputQueueDrops> ifInDiscards。

摘要

locIfInputQueueDrops =队列限制丢弃+无缓冲区丢弃ifInDiscards =无缓冲区丢弃（并且是locIfInputQueueDrops的子集）

locIfOutputQueueDrops和ifOutDiscards在计算相同事件时始终相等。这些事件达到输出队列限制，并且当数据包从一个接口快速切换到另一个接口时没有硬件tx缓冲区。以前的MIB对象的OID是：

来自OLD-CISCO-INTERFACES-MIB（仅限注册用户） 来自RFC1213-MIB（仅限注册用户）
locIfInputQueueDrops = .1.3.6.1.4.1.9.2.2.1.1.26 ifInDiscards = .1.3.6.1.2.1.2.2.1.13
locIfOutputQueueDrops = .1.3.6.1.4.1.9.2.2.1.1.27 ifOutDiscards = .1.3.6.1.2.1.2.2.1.19







问：我可以在路由器上轮询没有缓冲区吗？




答：是的。您可以轮询ifInDiscards以便轮询没有缓冲区。




问：如何在路由器上轮询队列限制丢弃？




答：使用SNMP，show interfaces命令无法打破输入丢弃的各个元素。

考虑有关输出丢弃计数器内容的新信息：

输入丢弃=队列限制丢弃+限制丢弃+ SMT队列完全丢弃+ RSRB丢弃+无缓冲丢弃

此外，即使清除了接口，也不会清除SNMP计数器。

https://www.cisco.com/c/en/us/support/docs/ip/simple-network-management-protocol-snmp/26007-faq-snmpcounter.html

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