Ethernet network high availability (link aggregation, LACP mode, static manual mode)

2.9.0 Ethernet Network High Availability (Link Aggregation, LACP Mode, Static Manual Mode)

1. Introduction:

Network reliability : the ability to ensure uninterrupted network services when a single point or multiple points of failure occur on the network

1. Board reliability:

• The following are rack-mounted devices and the names of the corresponding panels.

• Main control board MPU (responsible for control plane and management plane)

• Circuit board LPU (provides data forwarding function module)

• Switch fabric unit SFU (responsible for the data plane)

1.1. Realize the reliability improvement of the cabinet type:

2. Equipment reliability

• By adding multiple devices for stacking/clustering or through protocols with redundant pair functions such as STP and VRRP , it can effectively solve single-point and multi-point failures.
  

3. Link reliability

• Bind multiple logical links into one logical interface to increase link bandwidth without loops.
  

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1. Ethernet link aggregation (Eth-Trunk)

Link aggregation is to bundle multiple physical interfaces into one logical interface for the purpose of increasing link bandwidth, improving reliability, and providing load sharing.

1. Introduction to nouns:

• Aggregation group (LAG, Link Aggreation Group) : A logical link formed by bundling multiple links together. Each logical link corresponds to a logical interface. This logical interface is also called link aggregation interface/Eth-Trunk interface .
• Member interface : refers to the physical interfaces that make up the Eth-Trunk interface
• Member link : the link corresponding to the member interface
• Active interface and active link : The active interface is also called "Selected" and refers to the member interface participating in data forwarding. The link corresponding to the active interface is the active link (Active Link)
• Inactive interface and inactive link : An inactive interface is also called "Unselected" and refers to a member interface that does not participate in data forwarding. The link corresponding to the inactive interface is the inactive link (Inactive Link)
• Aggregation mode : there is LACP mode (Link Aggregation Control Protocol), manual mode

2. The difference between LACP mode and manual mode

 The default link aggregation mode is manual mode , and member interfaces are added manually. In manual mode, all active links participate in data forwarding and load sharing traffic. If an active link fails, the link aggregation group will automatically share the traffic evenly among the remaining active links.

 In LACP mode , after manually adding member interfaces, it looks almost the same as manual mode by default. However, LACP can control some links to be active links. If an active link fails, the link aggregation group automatically selects a link among the inactive links as the active link to participate in data forwarding, improving the Eth-Trunk Fault tolerance, providing backup function. LACP supports packet exchange, and exchanges information such as its own LACP priority and interface LACP priority through LACP packets.

3. LACP link aggregation configuration

Perform link aggregation on G0/0/1~G0/0/2 of LSW1 and LSW2, and the mode is LACP.

[LSW1]int Eth-Trunk 1 
[LSW1-Eth-Trunk1]mode lacp
[LSW1-Eth-Trunk1]trunkport g0/0/1
[LSW1-Eth-Trunk1]trunkport g0/0/2
[LSW1-Eth-Trunk1]port link-type trunk
[LSW1-Eth-Trunk1]port trunk allow-pass vlan all

[LSW2]int eth-trunk 1
[LSW2-Eth-Trunk1]trunkport g0/0/1
[LSW2-Eth-Trunk1]trunkport g0/0/2
[LSW2-Eth-Trunk1]mode lacp
[LSW2-Eth-Trunk1]port link-type trunk
[LSW2-Eth-Trunk1]port trunk allow-pass vlan all

#查看配置结果
<LSW1>display eth-trunk 1  
Eth-Trunk1's state information is:
Local:
LAG ID: 1                   WorkingMode: LACP【工作模式】                      
Preempt Delay: Disabled     Hash arithmetic: According to SIP-XOR-DIP         
System Priority: 32768      System ID: 30c5-0fd0-1160                         
Least Active-linknumber: 1  Max Active-linknumber: 32                         
Operate status: up          Number Of Up Port In Trunk: 2                     
--------------------------------------------------------------------------------
ActorPortName          Status   PortType PortPri PortNo PortKey PortState Weight
GigabitEthernet0/0/1   Selected 1GE      32768   1      305     10111100  1     
GigabitEthernet0/0/2   Selected 1GE      32768   2      305     10111100  1     

Partner:
--------------------------------------------------------------------------------
ActorPortName          SysPri   SystemID        PortPri PortNo PortKey PortState
GigabitEthernet0/0/1   32768    30c5-0fd0-1210  32768   1      305     10111100
GigabitEthernet0/0/2   32768    30c5-0fd0-1210  32768   2      305     10111100