Eth-Trunk

一、Eth-Trunk的技术背景

1. STP/MSTP：调节流量----》STP太多造成难以维护---->不推荐
2. 升级链路带宽 万兆光模块成本高，---->不推荐

二、Eth-Trunk 如何实现

以太网链路聚合Eth-Trunk简称 链路聚合，它通过将多条以太网物理链路捆绑在一起成为一条 逻辑链路，从而实现 增加链路带宽 的目的。
同时，这些捆绑在一起的链路通过相互间的动态备份，可以有效地 提高链路的可靠性。

使用手动 或 lacp协议来实现

Convergence of Eth-Trunk's links by condensing them with the Tainet's physical links into a logical link, thus achieving the purpose of increasing the bandwidth of the links.
At the same time, these bound links can effectively increase the reliability of the links through dynamic backups between them.
by hand or lacp

三、Eth-Trunk 技术原理

根据不同的链路聚合模式，Eth-Trunk接口可以实现增加带宽、负载分担等，帮助提高网络的可靠性。
Eth-Trunk可以用于二层的链路聚合，也可以用于三层的链路聚合。缺省情况下，以太网接口工作在二层模式。如果需要配置二层Eth-Trunk接口，可以通过portswitch命令将该接口切换成二层接口；如果需要配置三层Eth-Trunk接口，可以通过undo portswitch命令将该接口切换成三层接口。

The Eth-Trunk interface can help improve network reliability by increasing bandwidth, load sharing, and so on, depending on the different modes of chain polymerization.
Eth-Trunk can be used for two-storey or three-storey connection. In default, the Eth-Trunk interface works in two-storey mode. If you need to configure the two-storey Eth-Trunk interface, you can switch it to two-storey interfaces by portswitch command; if you need to configure the three-storey Eth-Trunk interface, you can switch it to three-storey interfaces by undo portswitch command.

1. 手工：
   手工模式下，Eth-Trunk的建立、成员接口的加入由手工配置，没有链路聚合控制协议LACP的参与。
   当需要在两个直连设备之间提供一个较大的链路带宽而设备又不支持LACP协议时，可以使用手工模式。
   手工强制指定，Eth-trunk内的所有接口都要进行流量转发，并且每条链路的流量负载均衡
   
2. lacp的形式：
   on:不用协商，双方都设置为lacp的on,Eth-Trunk捆绑
   actice:主动协商，对方是否成为Eth-Trunk捆绑
   passive:被动地等待对方提问
   off:不愿意配置为Eth-Trunk捆绑
   
3. 端口的负载分担：

   • 逐流负载分担
     当报文的源IP地址、目的IP地址都相同或者报文的源MAC地址、目的MAC地址都相同时，这些报文从同一条成员链路上通过。

     When the source IP address, the destination IP address, or the source MAC address and the destination MAC address are the same, the report passes through the same chain of members.

   • 逐包负载分担---》不推荐的配置
     以报文为单位分别从不同的成员链路上发送。

     The package-by-load allocation -- the unrecommended configuration
     is sent separately from the various member links in the form of a message.

四、Eth-Trunk的配置

• 手工配置
  
• lacp配置
  

五、Eth-trunk的实施要点

1. 只能删除 不包含任何成员端口 的Eth-Trunk端口。

   Only remove the Eth-Trunk port that does not contain any member port.

2. 二层的Eth-Trunk端口的成员端口必须是二层的接口；三层的Eth-Trunk端口的成员端口必须是三层的接口。 三层接口就是路由器的接口，能配IP地址的接口，不能加到vlan里，也不能做trunk

   The port of the Eth-Trunk port on the second floor must be the interface of the second floor; the port of the Eth-Trunk port on the third floor must be the interface of the three layers.

3. 一个Eth-Trunk端口最多可以加入 8个成员端口。

   An Eth-Trunk port may be added to a maximum of eight member ports.

4. 加入Eth-Trunk端口的接口类型必须是Hybrid接口（Access与Trunk类型的端口无法加入）。
   要假如eth-trunk的接口不能做成access或者trunk，需要在eth-trunk 接口配置完后，再对eth-trunk 进行access或者trunk的配置

   The interface type for joining the Eth-Trunk port must be the Hybrid interface (access and Trunk-type ports cannot be joined).
   If the Eth-trunk interface is not available for access or trunk, then access or trunk will need to be configured after the Eth-trunk interface is finished.

5. Eth-Trunk端口不能作为其他Eth-Trunk端口的成员端口。

   The Eth-Trunk port cannot be a member port for other Eth-Trunk ports.

6. 同一个以太网接口只能属于一个Eth-Trunk端口。

   The same Ethernet interface can only belong to an Eth-Trunk port.

7. 同一个Eth-Trunk端口下的成员 端口的类型必须一致。

   The same Eth-Trunk port member must have the same type of port.

8. 如果本端设备接口加入了Eth-Trunk端口，与该接口直连的对端接口也必须加入Eth-Trunk端口，两端才能正常通信。

   If the current device interface is added to the Eth-Trunk port, the interface directly with the interface must also be added to the Eth-Trunk port before the two ends can communicate properly.

9. 如果成员端口的 速率 不同，速率低的接口可能会发送拥塞，造成报文的丢失。配置eth-trunk的两端的接口速率要一致（速率：Ethernet 0/0/1 10M / fastEthernet 100M / G0/0/1 千兆）

   If the speed of the port of the member differs, the low speed interface may send congestion, causing loss of the message. The two ends of the configuration Eth-trunk should have the same speed of the interface (rate: Ethernet 0/0/1 10M/fastEthernet 100M / G0/0/1 gigabytes)

10. 接口加入Eth-Trunk端口后，成员端口不再学习MAC地址，Eth-Trunk端口进行MAC地址的学习。

    After the interface is added to the Eth-Trunk port, the member port will no longer study the MAC address and the Eth-Trunk port will study the MAC address.

六、Eth-trunk的抢占

1. LACP模式活动链路的选取
   
   首先根据系统优先级进行选举主动端，LACP的系统优先级默认为32768，范围0-65535，值越小越优，如果系统优先级相同则比较系统ID，小的成为主动端。
   比较完主动端后，根据主动端的接口优先级来选取活动端口，接口优先级越小越优，默认为32768，范围0-65535。接口优先级相同则比较接口ID，即接口号，越小越优。而对端根据主动端选取的活动接口对应自己的活动接口，剩下的则成为备份端口。

   The selection of
   >br> starts with the electoral initiative based on system priorities, with a system priority default of 32768, with a range of 0-65535, the smaller the value being, the smaller the system ID if the system priority is the same, and the smaller the active interface is the better if the system priority is the same.
   After a comparison of the active end, the lower the priority of the interface is selected according to the active end priority level, the smaller the priority of the interface being the lower, defaulted to 32768, range 0-6535. The interface priority is the same as the interface ID, the interface number, the smaller the smaller.

2. LACP模式的抢占机制（接口优先级 默认32768， 越小越优先）
   
   当活动端口port1发生故障后转为备份端口，而备份端口port3成为活动端口来接替工作，这时候如果port1恢复正常，设备使能了LACP抢占功能的话则根据抢占时延来进行抢占，时延结束port1重新成为活动端口而port3变为了备份端口，如果没有使能LACP抢占功能，则port1不会进行抢占，一直处于备份端口。抢占时延可进行配置。

   
   when activity port 1 malfunctions and back-port3 becomes the back-up port to replace work. If port 1 returns to function as activity port, the equipment will be seized depending on the duration of the seizure, closing port 1 becomes the back-up port and port 3 becomes the back-up port if it does not enable LACP to take over functions, the back-up port will not take over and will remain at the back-up port.

七、Eth-trunk的优点

• 增加带宽
  链路聚合接口的最大带宽可以达到各成员接口带宽之和。

  The maximum bandwidth of an additional bandwidth
  link polymer interfaces can reach the sum of the bandwidth of the interfaces of each member.

• 提高可靠性
  当某条活动链路出现故障时，流量可以切换到其他可用的成员链路上，从而提高链路聚合接口的可靠性。互为备份。

  Improves reliability
  . When there is a malfunction in an active link, the flow changes to other available member links, thereby increasing the reliability of the connection polymer interface.

• 负载分担
  在一个链路聚合组内，可以实现在各成员活动链路上的负载分担。

  The load-sharing