Introduction to Link Aggregation
Ethernet link aggregation Eth-Trunk is referred to as link aggregation. It bundles multiple Ethernet physical links together to form a logical link.
In this way, the purpose of increasing the link bandwidth is achieved. At the same time, these bundled links can effectively improve link reliability through mutual dynamic backup.
Purpose:
Link aggregation technology can increase link bandwidth by bundling multiple physical interfaces into one logical interface without hardware upgrade.
While achieving the purpose of increasing the bandwidth, link aggregation adopts the mechanism of backup links, which can effectively improve the reliability of links between devices.
Link aggregation has the following three main advantages:
Increase bandwidth The maximum bandwidth of a link aggregation interface can reach the sum of the bandwidths of all member interfaces.
Improved reliability When an active link fails, traffic can be switched to other available member links, thereby improving the reliability of the link aggregation interface.
Load sharing In a link aggregation group, load sharing can be realized on active links of each member.
Link aggregation mode is divided into two types: manual load sharing, LACP
Manual load sharing
All active links participate in data forwarding and share traffic evenly
LACP
Negotiate through LACP packets to determine active and inactive interfaces
1. Purpose of the experiment
Two configuration methods of Eth-Trunk, Eth-Trunk improves bandwidth and load balance.
2. Experimental topology
3. Experimental operation
manual configuration
LSW1:
interface Vlanif1
ip address 192.168.10.1 255.255.255.0
interface Eth-Trunk1
mode manual load-balance #Eth-Trunk The default mode is manual. After typing this command, dis curr is not displayed on the Eth-Trunk 1 interface#
interface GigabitEthernet0/0/1
eth-trunk 1
interface GigabitEthernet0/0/2
eth-trunk 1
interface GigabitEthernet0/0/3
eth-trunk 1
LSW2：
interface Vlanif1
ip address 192.168.10.2 24 255.255.255.0
interface Eth-Trunk1
mode manual load-balance
trunkport GigabitEthernet0/0/1 #This configuration method is different from the configuration of the three ports of LSW1, but the effect is the same#
trunkport GigabitEthernet0/0/2
trunkport GigabitEthernet0/0/3
Check that Eth-Trunk 1 of LSW1 and the associated physical ports are all up. The weight of the three physical ports is 1:1:1, indicating that the load is balanced and the bandwidth is 3G.
Check that Eth-Trunk 1 of LSW2 and the associated physical ports are all up. The weight of the three physical ports is 1:1:1, indicating that the load is balanced and the bandwidth is 3G.
Configuration instructions
Eth-Trunk port number is optional between 0-63, there are 2 modes, lacp-static, manual (manual mode)
In manual mode, no verification is required, and the interface will be UP when Eth-Trunk is enabled at one end;
The figure below shows that there is no associated physical port on LSW1 and the display is down.
LSW2 is already UP, indicating that no negotiation is required.
LACP-Static configuration
For LACP-Static auto-negotiation, both ends must be configured as LACP to get up.
The figure below is a screenshot with only one end configured
LSW1:
interface Vlanif1
ip address 192.168.10.1 255.255.255.0
interface Eth-Trunk2
mode lacp-static #LACP-Static模式#
interface GigabitEthernet0/0/1
eth-trunk 2
interface GigabitEthernet0/0/2
eth-trunk 2
interface GigabitEthernet0/0/3
eth-trunk 2
LSW2：
interface Eth-Trunk2
interface Vlanif1
ip address 192.168.10.2 255.255.255.0
mode lacp-static #LACP-Static模式#
interface GigabitEthernet0/0/1
eth-trunk 2
interface GigabitEthernet0/0/2
eth-trunk 2
interface GigabitEthernet0/0/3
eth-trunk 2
View Eth-Trunk 2 on LSW1
View Eth-Trunk 2 on LSW2
Eth-Trunk 2 at both ends are up.
ping test
Modify the number of link aggregation links
Normally, the physical ports associated with Eth-Trunk 2 on LSW1 and LSW2 are Selected, data forwarding ports. And it supports up to 8 link aggregations.
Change the maximum link aggregation number of Eth-trunk 2 on LSW1 to 2, max active-linknumber 2
It is found that two of the physical interfaces associated with Eth-Trunk 2 on LSW1 and LSW2 are selected and the other is unselected, which become backup links.
We simulate disconnecting a selected link, and observe the change of the previously unselected link. Disconnect G0/0/1 of LSW1, and G0/0/3, which was the backup link before, becomes selected.
Layer 3 Eth-Trunk Link Aggregation
The only difference from Layer 2 link aggregation is that IP configuration is done under the Layer 3 Eth-Trunk logical interface.
4. Experiment summary
Eth-Trunk link aggregation increases bandwidth and improves link reliability, and the configurations at both ends must be consistent.