LACP是什么御板？
基于IEEE802.3ad標(biāo)準(zhǔn)的LACP锥忿，英文全稱 Link Aggregation Control Protocol， 翻譯成中文叫做鏈路匯聚控制協(xié)議怠肋，用于實(shí)現(xiàn)鏈路動(dòng)態(tài)匯聚與解匯聚敬鬓。
LACP通過LACPDU與對(duì)端交互信息。DU指Data Unit笙各，數(shù)據(jù)單元钉答。可以向?qū)Χ送ǜ鍹AC地址杈抢，優(yōu)先級(jí)数尿，端口號(hào)，Key等惶楼。對(duì)端接收到信息后右蹦，通過與其保存的信息進(jìn)行比較和計(jì)算，確定加入或退出某個(gè)匯聚組鲫懒。
主要用來干啥呢嫩实？對(duì)刽辙，匯聚嘛窥岩，當(dāng)然是用來做端口匯聚。還可以做負(fù)載分擔(dān)宰缤，鏈路備份（自動(dòng)倒換）颂翼。
注意，手工配置的負(fù)載分擔(dān)慨灭，配置基本的Eth-Trunk接口模式朦乏，不需配置LACP，成員接口（selected）都參與數(shù)據(jù)轉(zhuǎn)發(fā)氧骤。
配置LACP的話呻疹，可以配置成靜態(tài)或動(dòng)態(tài)。區(qū)別在于筹陵，靜態(tài)模式下刽锤，成員接口都是手工配置加入，但那些接口是selected朦佩，那些是standby的則由LACP協(xié)議決定并思。動(dòng)態(tài)模式下，包括成員接口的加入语稠，活動(dòng)接口的選擇宋彼，都是由LACP協(xié)議決定弄砍，即使說，啟動(dòng)動(dòng)態(tài)LACP的設(shè)備不需創(chuàng)建Eth-Trunk接口输涕，也不需要指定接口音婶。
使用LACP協(xié)議的時(shí)候，Selected和Standby端口都能收發(fā)LACPDU占贫， 但standby接口不轉(zhuǎn)發(fā)用戶報(bào)文桃熄。
另外，在使用LACP的情況下型奥，無論是靜態(tài)匯聚還是動(dòng)態(tài)匯聚瞳收，看到的standby端口狀態(tài)是down的。
下面看一下實(shí)際案例厢汹，
Huawei NE05E G0/2/4及G0/2/5 兩個(gè)10G口做Trunk與OLT(MA5800X7)組網(wǎng)雙上行(0/8/0 1, 0/9/0 1)配置如下：

#NE05E:
#
interface Eth-Trunk15
 portswitch
 port trunk allow-pass vlan 1 to 100
 mode lacp-static
 load-balance l4
#
interface GigabitEthernet0/2/4
 undo shutdown
 eth-trunk 15
 dcn
#
interface GigabitEthernet0/2/5
 undo shutdown
 eth-trunk 15
 dcn
#
#MA5800X7:
[lacp-config]
  <lacp-config>
 link-aggregation lacp-key 0/8/0 1
 link-aggregation add-member 0/8/0 0/9 0
 link-aggregation add-member 0/8/0 0/9 1
 link-aggregation add-member 0/8/0 0/9 2
 link-aggregation add-member 0/8/0 0/9 3
#

在MA5800的配置里螟深，實(shí)際上display current的時(shí)候看不到類似“ link-aggregation add-member 0/8/0 0/9 0” 這些語句，但是可以通過不同命令來查看烫葬。 下面“display lacp link-aggregation summary” 可以看到selected端口有2個(gè)界弧，standby的有6個(gè)，分別對(duì)應(yīng)0/8/0 和0/9/0 和其余6個(gè)未selected的端口（其實(shí)這些端口都沒有物理連接搭综，主要是兩個(gè)10G口上行就足夠了垢箕，光模塊省點(diǎn)用)

(config)#display lacp link-aggregation summary
{ <cr>||<K> }:

  Command:
          display lacp link-aggregation summary
  Actor
   Priority           : 32768     MAC Address: 7858-6000-e7ab
   Short Period       : 1  s      Long Period: 30 s
   Priority Preemption: Disable   Timeout    : Fast
  ----------------------------------------------------------------------------
  Agg  Partner  Partner         Select Standby Load    Backup  Master    Admin
  ID   Pri      MAC             Ports  Ports   Sharing Protect Port      Key
  ----------------------------------------------------------------------------
  1    32768    80b5-75c2-27e5  2      6       YES     NO      0 /8 /0   1
  ----------------------------------------------------------------------------
(config)#display lacp link-aggregation verbose 1
{ <cr>||<K> }:

  Command:
          display lacp link-aggregation verbose 1
  System Priority : 32768
  MAC Address     : 7858-6000-e7ab
  Protect Mode    : Non-BackupProtect
  Admin Key       : 1
  Preempt Delay(s): 0

  Master Port: 0/8/0
  Actor    Port Priority  : 16384     Oper-key   : 1
           Port Role      : SELECTED  Port Status: C&D
  Partner  System Priority: 32768     MAC Address: 80b5-75c2-27e5
           Port Priority  : 32768     Oper-key   : 3905

  Sub Port: 0/9/0
  Actor    Port Priority  : 16384     Oper-key   : 1
           Port Role      : SELECTED  Port Status: C&D
  Partner  System Priority: 32768     MAC Address: 80b5-75c2-27e5
           Port Priority  : 32768     Oper-key   : 3905

  Sub Port: 0/8/1
  Actor    Port Priority  : 16384     Oper-key   : 0
           Port Role      : STANDBY   Port Status: Non-C&D

  Sub Port: 0/8/2
  Actor    Port Priority  : 16384     Oper-key   : 0
           Port Role      : STANDBY   Port Status: Non-C&D

  Sub Port: 0/8/3
  Actor    Port Priority  : 16384     Oper-key   : 0
           Port Role      : STANDBY   Port Status: Non-C&D
 Sub Port: 0/9/1
  Actor    Port Priority  : 16384     Oper-key   : 0
           Port Role      : STANDBY   Port Status: Non-C&D

  Sub Port: 0/9/2
  Actor    Port Priority  : 16384     Oper-key   : 0
           Port Role      : STANDBY   Port Status: Non-C&D

  Sub Port: 0/9/3
  Actor    Port Priority  : 16384     Oper-key   : 0
           Port Role      : STANDBY   Port Status: Non-C&D

看一下路由器上的統(tǒng)計(jì)：

[~NE05E_01]disp lacp brief
System Priority: 32768
System ID      : 80b5-75c2-27e5

[~NE05E_01]disp lacp statistics eth-trunk 15
 Eth-Trunk15's PDU statistic is:
 -------------------------------------------------------------------------------
 Port                      LacpRevPdu  LacpSentPdu  MarkerRevPdu  MarkerSentPdu
 GigabitEthernet0/2/4      764414      23278073     0             0
 GigabitEthernet0/2/5      764422      23278081     0             0

[~NE05E_01]disp int Eth-Trunk 15
Eth-Trunk15 current state : UP (ifindex: 38)
Line protocol current state : UP
Link quality grade : GOOD
Description:
Switch Port, TPID : 8100(Hex), Hash arithmetic : According to flow,Maximal BW: 20Gbps, Current BW: 20Gbps, The Maximum Transmit Unit(L3) is 1500 bytes
Internet protocol processing : disabled
IP Sending Frames' Format is PKTFMT_ETHNT_2, Hardware address is 80b5-75c2-27e5
Current system time: 2019-05-17 23:11:49
Physical is ETH_TRUNK
    Last 300 seconds input rate 817341 bits/sec, 914 packets/sec
    Last 300 seconds output rate 23899360 bits/sec, 2080 packets/sec
    Input: 2349976240 packets,344045983992 bytes
           2308742671 unicast,39406270 broadcast,1827299 multicast
           0 errors,0 drops
    Output:5942717725 packets,8154570342640 bytes
           5814368771 unicast,77054633 broadcast,51294321 multicast
           0 errors,0 drops
    Last 300 seconds input utility rate:  0.01%
    Last 300 seconds output utility rate: 0.11%
----------------------------------------------------------
PortName                      Status              Weight
----------------------------------------------------------
GigabitEthernet0/2/4          UP                  1
GigabitEthernet0/2/5          UP                  1
----------------------------------------------------------
The Number of Ports in Trunk : 2
The Number of UP Ports in Trunk : 2

[~NE05E_01]disp eth-trunk 15
Eth-Trunk15's state information is:
Local:
LAG ID: 15                      WorkingMode: STATIC
Preempt Delay: Disabled         Hash arithmetic: According to flow
System Priority: 32768          System ID: 80b5-75c2-27e5
Least Active-linknumber: 1      Max Active-linknumber: 8
Operate status: up              Number Of Up Ports In Trunk: 2
Timeout Period: Slow
--------------------------------------------------------------------------------
ActorPortName          Status   PortType PortPri PortNo PortKey PortState Weight
GigabitEthernet0/2/4   Selected 10GE     32768   1      3905    10111100  1
GigabitEthernet0/2/5   Selected 10GE     32768   2      3905    10111100  1

Partner:
--------------------------------------------------------------------------------
ActorPortName          SysPri   SystemID        PortPri PortNo PortKey PortState
GigabitEthernet0/2/4   32768    7858-6000-e7ab  16384   1      1       11111100
GigabitEthernet0/2/5   32768    7858-6000-e7ab  16384   5      1       11111100

我做了鏈路測(cè)試一切正常，細(xì)節(jié)不說了兑巾。
順便說一下条获，我這還有一些Adtran OLT TA5000系列，雙主控板上行鏈路匯聚叫做Cross-slot LAG, 配置如下(配置lag的時(shí)候要看當(dāng)前主用板是那塊蒋歌，1/A就用下面模板帅掘，1/B的話相應(yīng)修改）：

interface ten-gigabit-ethernet 1/A/1
  lacp mode active
  no shutdown
  exit

interface ten-gigabit-ethernet 1/B/1
  lacp mode active
  no shutdown
  exit

lacp response-mode 1/A interactive

interface lag-group 1/A/1
  cross-slot
  alias "LAG1"
  link ten-gigabit-ethernet 1/A/1
  link ten-gigabit-ethernet 1/B/1
  active-links-minimum 1
  no shutdown
  exit

no ethernet default interface

ethernet default interface lag-group LAG1

查看狀態(tài)：

OL02-EAS-LON#sh int lag
lag-group 1/B/1 is IS And up
  Alias                           : LAG1
  Cross-Slot                      : enabled
  Minimum Active Links            : 1
  Active Links                    : 2
  Link                            : ten-gig-eth 1/B/1 (UP)
  Link                            : ten-gig-eth 1/A/1 (UP)