link aggregation
Link aggregation technology can bundle multiple physical interfaces into one logical interface without relying on hardware upgrades, which not only increases link bandwidth, but also effectively improves the reliability of links between devices.
Link Aggregation Meaning
Regardless of the access layer, aggregation layer or core layer, link aggregation is a bundling technology that can bundle multiple Ethernet links into one logical Ethernet link.
When multiple Ethernet links are used to connect two devices in a link aggregation design, the bandwidth of all links can be fully used to forward the traffic between the two devices.
Using a Layer 3 link to connect two devices can save IP addresses.
basic concept
1. Aggregation group: a collection of Ethernet ports
Classification: Layer 2 Aggregation Group, Layer 3 Aggregation Group
2. Aggregation member port status:
selected: Can participate in forwarding user traffic.
unselect: Do not participate in the forwarding of user traffic.
3. Implementation of Link Aggregation
link-aggregation group: used for Ethernet link aggregation on the switch.
IP-trunk group: used for link aggregation of routers, switches, and BASs with POS interfaces.
Eth-Trunk group: used for aggregation of Ethernet interfaces of switches, routers, and BASs.
link aggregation mode
1. Manual Mode
Using the manual mode of Eth-Trunk is like configuring static routing or setting the port rate locally. It is a localized and static operation mode for function settings.
The Eth-Trunk established in manual mode is more stable than dynamically learned routes, but lacks flexibility.
If a link fails, the devices on both sides can detect it, and no longer use the failed link, but continue to use the normal link to send data.
2. LACP mode
Provides the standard for negotiating and maintaining Eth-Trunk for link aggregation devices. When configuring an Eth-Trunk in LACP mode, you need to create Eth-Trunk logical ports on both devices first, then configure the ports in LACP mode, and finally add the physical ports to be bundled to the Eth-Trunk.
First, two switches exchange LACPDUs (LACP data units), and use the system priority to determine who is the active end. If the priorities are the same, the switch with the smaller MAC address will become the LACP active end.
After the active end is determined, the LACP priority of each port on the LACP active end will be compared in turn. The N ports with the highest port priority will establish Eth-Trunk active links with the peer end, and the rest will establish Eth-Trunk with the peer end. Backup link.
Link Aggregation Configuration
1. Manual configuration
int eth-trunk 1 //取值范围0～63
trunkport g0/0/1 t0 0/0/2
port link-type trunk
port trunk allow-pass vlan all2. lacp configuration
int eth-trunk 1
mode lacp-static
trunkport g0/0/1 to 0/0/2the case
1. Configure SW1
2. Configure SW2
result graph
