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 <command> [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 <argument list>
- "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 TLV 120 System Name TLV xx-xx-CE5850-xxxxx #交换机设备名 System Description TLV Huawei Versatile Routing Platform Software VRP (R) software, Version 8.150 (CE5855EI V200R002C50SPC800) Copyright (C) 2012-2017 Huawei 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: 4 OID: +[) Port VLAN ID TLV PVID: Port and Protocol VLAN ID TLV PVID: 0, not supported, not enabled VLAN Name TLV VID 3652: Name VLAN3652 MAC/PHY Configuration Status TLV Auto-negotiation supported and enabled PMD auto-negotiation capabilities: 0xxxxx MAU type: 1000 BaseXFD Link Aggregation TLV Aggregation capable Currently not aggregated Aggregated Port ID: 0 Maximum Frame Size TLV 9216 End 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 for interface 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 adminStatus for all interfaces #让所有网口都不可用LLDP lldptool set-lldp adminStatus=disabled Query the LLDP adminStatus for interface eth3 #查询网口eth3的LLDP状态 lldptool -l -i eth3 adminStatus lldptool get-lldp -i eth3 adminStatus Query the LLDP statistics for interface eth3 #查询网口eth3的统计信息 lldptool -S -i eth3 adminStatus lldptool stats -i eth3 adminStatus Query the local TLVs which are being transmitted for a 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 6 Disable transmit of the IEEE 802.3 MAC/PHY Configuration Status TLV for a 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 TLV for all interfaces: lldptool -T -V portDesc enableTx=yes lldptool set-tlv -V 4 enableTx=yes Query value of the transmit setting for the Port Description TLV for a 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 address 192.168.10.10 lldptool -T -i eth3 -V mngAddr ipv4=192.168.10.10 Set a Management Address TLV on eth3 to carry IPv6 address ::192.168.10.10 lldptool -T -i eth3 -V mngAddr ipv6=::192.168.10.10 Get the configured IPv4 address for the Management Address TLV on eth3 lldptool -t -i eth3 -V mngAddr - c ipv4 Get all configured attributes for the Management Address TLV on eth3 lldptool -t -i eth3 -V mngAddr -c Query the current DCBX mode that will be used if lldpad 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 in IEEE DCBX mode) after the next lldpad restart lldptool -T -i eth3 -V IEEE-DCBX mode=reset Enable transmit of the Edge Virtual Bridging TLV for interface 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 VDP for interface eth4 lldptool -i eth4 -T -V vdp enableTx=yes Configurations per port have higher precedence than global configurations.