1. 描述

当我们想在操作系统里面查看网口和交换机连接的状态信息，我们可以使用lldptool这个工具。

2.LLDP协议

LLDP是一个数据链路层发现协议，LLDP协议使得接入网络的一台设备可以将其主要的能力，管理地址，设备标识，接口标识等信息发送给接入同一个局域网络的其它设备。lldptool工具采用的是LLDP协议，一般我们使用lldptool是为了得到设备的物理拓扑结构以及管理配置信息，比如说，和eth1网口相连的网络交换机的Vlan ID是多少？网络交换机的名称是什么？网线插在网络交换机的什么地方？

在这里我们不去讨论LLDP协议的架构和具体时序状态码等，这里仅仅介绍怎么用它。

LLDP协议有四种工作模式：

TxRx：既发送也接收LLDP 帧

Tx    ：只发送不接收LLDP 帧

Rx：只接收不发送LLDP 帧

Disable：既不发送也不接收

一般设置LLDP工作在TxRx模式。

3.lldptool的命令格式

lldptool [options] [参数]

Options

-i [ifname]

specifies the network interface to which the command applies

-V [tlvid]

specifies the TLV identifier

The tlvid is an integer value used to identify specific LLDP TLVs. The tlvid value is the Type value for types not equal to 127 (the organizationally specific type). For organizationally specific TLVs, the tlvid is the value represented by the 3 byte OUI and 1 byte subtype - where the subtype is the lowest order byte of the tlvid.

The tlvid can be entered as a numerical value (e.g. 10 or 0xa), or for supported TLVs, as a keyword. Review the

lldptool help output to see the list of supported TLV keywords.

-n

"neighbor" option for commands which can use it (e.g. get-tlv)

-g [bridge scope]

specify the bridge scope this command operates on. Allows to set and query all LLDP TLV modules for "nearest_bridge" (short: "nb"), "nearest_customer_bridge" ("ncb") and "nearest_nontpmr_bridge" ("nntpmrb") group mac addresses. Configurations are saved into independent sections in lldpad.conf. If no bridge scope is supplied this default to "nearest bridge" to preserve the previous behaviour.

-c

"config" option for TLV queries. Indicates that the query is for the configuration elements for the specified TLV. The argument list specifies the specific elements to query. If no arguments are listed, then all configuration elements for the TLV are returned.

-r

show raw client interface messages

-R

show only raw Client interface messages

Commands

license

show license information

-h, help

show usage information

-v, version

show version information

-S, stats

get LLDP statistics

-t, get-tlv

get TLV information

-T, set-tlv

set TLV information

-l, get-lldp

get LLDP parameters

-L, set-lldp

set LLDP parameters

-q, quit

exit from interactive mode

4.lldptool使用举例

ip a查看启用网口：

先看一些有没有lldptool工具，如果没有的话yum装一下：

[root@wow ~]# service lldpad status

lldpad is stopped

[root@wow~]# service lldpad start

Starting lldpad: [ OK ]

[root@wow~]#

先设置lldptool的工作模式：

[root@wow ~]# lldptool set-lldp -i eth0 adminStatus=rxtx

adminStatus= rxtx　　#这样就和网络交换机建立了邻居关系，接下来就可以查询连接的交换机信息了

使用lldptool查看网口与交换机连接状态：

[root@wow ~]# lldptool -t -n -i eth0

Chassis ID TLV

MAC:48:xx:xx:xx:xx:51　　#mac地址Port ID TLV

Ifname: GE1/0/1#网线插在交换机上的端口位置Time to Live TLV120System Name TLV

xx-xx-CE5850-xxxxx#交换机设备名System Description TLV

Huawei Versatile Routing Platform Software

VRP (R) software, Version8.150(CE5855EI V200R002C50SPC800)

Copyright (C)2012-2017Huawei Technologies Co., Ltd.

HUAWEI CE5855-xxxx-xxx　　#华为的交换机

System Capabilities TLV

System capabilities: Bridge, Router

Enabled capabilities: Bridge, Router

Management Address TLV

IPv4: xx.xxx.xxx.xx　　#ip地址

Ifindex:4OID:+[)

Port VLAN ID TLV

PVID:Port and Protocol VLAN ID TLV

PVID:0, not supported, not enabled

VLAN Name TLV

VID3652: Name VLAN3652

MAC/PHY Configuration Status TLV

Auto-negotiation supported and enabled

PMD auto-negotiation capabilities: 0xxxxxMAU type:1000BaseXFD

Link Aggregation TLV

Aggregation capable

Currently not aggregated

Aggregated Port ID:0Maximum Frame Size TLV9216End of LLDPDU TLV

[root@wow~]#

如果想利用lldptool对网口进行一些设置，可以参考手册，下面是在Linux上找男人看到的一些例子：

Configure LLDP adminStatus to Receive and Transmit forinterface eth2　　#为网口eth2配置LLDP的收发工作模式

lldptool-L -i eth2 adminStatus=rxtx

lldptool set-lldp -i eth2 adminStatus=rxtx

Disable the LLDP adminStatusforall interfaces　　#让所有网口都不可用LLDP

lldptool set-lldp adminStatus=disabled

Query the LLDP adminStatusforinterface eth3　　#查询网口eth3的LLDP状态

lldptool-l -i eth3 adminStatus

lldptool get-lldp -i eth3 adminStatus

Query the LLDP statisticsforinterface eth3 　　#查询网口eth3的统计信息

lldptool-S -i eth3 adminStatus

lldptool stats-i eth3 adminStatus

Query the local TLVswhich are being transmitted fora given interface: 　　#查询为给定接口传输的本地

lldptool-t -i eth3

lldptool get-tlv -i eth3

Query the received neighbor TLVs received on a given interface:　　#查询给定接口上收到的接收邻居TLV

lldptool-t -n -i eth3

lldptool get-tlv -n -i eth3

Query the value of the System Description TLV as received from the neighbor on a given interface:

lldptool-t -n -i eth3 -V sysDesc

lldptool get-tlv -n -i eth3 -V 6Disable transmit of the IEEE802.3 MAC/PHY Configuration Status TLV fora given interface:

lldptool-T -i eth3 -V macPhyCfg enableTx=no

lldptool set-tlv -i eth3 -V 0x120f01 enableTx=no

Enable transmit of the Port Description TLVforall interfaces:

lldptool-T -V portDesc enableTx=yes

lldptool set-tlv -V 4 enableTx=yes

Query value of the transmit settingfor the Port Description TLV fora given interface:

lldptool-t -V portDesc -c enableTx

lldptool get-tlv -V 4 -c enableTx

Set a Management Address TLV on eth3 to carry IPv4 address192.168.10.10lldptool-T -i eth3 -V mngAddr ipv4=192.168.10.10Set a Management Address TLV on eth3 to carry IPv6 address ::192.168.10.10lldptool-T -i eth3 -V mngAddr ipv6=::192.168.10.10Get the configured IPv4 addressforthe Management Address TLV on eth3

lldptool-t -i eth3 -V mngAddr-c ipv4

Get all configured attributesforthe Management Address TLV on eth3

lldptool-t -i eth3 -V mngAddr -c

Query the current DCBX mode that will be usediflldpad is restarted. (this is not a persistent setting)

lldptool-t-i eth3 -V IEEE-DCBX -c mode

Reset the DCBX mode to be'auto' (start inIEEE DCBX mode) after the next lldpad restart

lldptool-T -i eth3 -V IEEE-DCBX mode=reset

Enable transmit of the Edge Virtual Bridging TLVforinterface eth4

lldptool-i eth4-T -V evbCfg enableTx=yes

Configure EVB TLV to set reflective relay and RTE,ECP and VDP capabilities

lldptool-T -i eth4 -V evbCfg fmode=reflectiverelay

lldptool-T -i eth4 -V evbCfg capabilities=rte,ecp,vdp

Enable transmit of the VDPforinterface eth4

lldptool-i eth4 -T -V vdp enableTx=yes

Configurations per port have higher precedence than global configurations.