With the rapid development of society, the scale of network services and campuses is also expanding, and users are getting higher and higher in terms of bandwidth, security, and reliability of the network protocol, spanning tree protocol) to ensure the reliability of transmission, but this solution has the shortcomings of low flexibility, complex configuration, and long time to repair faults, which is not suitable for the development of today's society, so it derives the content we are talking about today - link aggregation technology.
1. Background of link aggregation
As the scale of the network continues to expand, the demand for bandwidth and reliability of the backbone link is also increasing. In general, higher speed interfaces are required on the backbone link to increase bandwidth, but this method is expensive and cumbersome and inflexible. Link aggregation technology can turn multiple physically existing interfaces into one logically existing interface to increase bandwidthWhile increasing the bandwidth, it can also implement backup links, which can improve the robustness and reliability of the network.
2. Application scenarios of link aggregation
Link aggregation can be used in a wide range of applications, such as in enterprise networks, on network trunks in various regions, or in local area networks. In a general enterprise network, all traffic must be aggregated to the core layer, and then from the devices in the core area to other networks, in which the data traffic is extremely large. Therefore, congestion is very likely to occur during high-speed data exchange at the core layer, so link aggregation technology is indispensable.
Link aggregation can improve link bandwidth. Theoretically, by aggregating several links, the bandwidth of an aggregation interface can be expanded to the sum of the bandwidths of all member ports, thus effectively increasing the bandwidth of the logical link. Link aggregation provides that reliability to the network. If a member interface fails, the physical link of the member interface switches traffic to another member link if link aggregation is configured.
3. Advantages of link aggregation
1. Improve the bandwidth of the link: Theoretically, through link aggregation, the maximum bandwidth of an aggregation port can be the sum of the bandwidth of all member ports.
2. Improve network reliability: If one of the ports is faulty, the traffic of the member port will be switched to the other member links. The reliability of network transmission is guaranteed.
3. Load balancing of traffic: distribute traffic evenly among all member links. Minimize the risk of traffic blocking the link by each member of the link.
1. The working mode of link aggregation
There are two modes of link aggregation: manual load balancing mode and LACP (Link Aggregation Control Protocol) mode.
Manual load balancing mode:
In manual mode, the establishment of eth-trunks and the addition of member interfaces are manually configured, and LACP is not used for negotiation between systems. Under normal circumstances, all links are active links, all active links participate in the data, evenly share the traffic, if an active link fails, the link aggregation group automatically shares the traffic evenly among the remaining active links. In manual mode, in order for the link aggregation interface to work properly, you must ensure that the peer interfaces of all member interfaces of the local link aggregation interface are joined by the same deviceThere is no packet interaction between devices, so the administrator can only confirm the packetsThe device can only determine whether the peer interface is working properly based on the physical layer status.
LACP (Link Aggregation Control Protocol) mode:
LACP mode is a link aggregation mode that uses the LACP protocol to interact with each other through the Link Aggregation Control Protocol (LACPDU) and ensures that the peer is a member of the same device and the same aggregation interface through protocol negotiation. LACPDU packets contain system priorities, such as device priority, MAC address, interface priority, and interface number. In LACP mode, the number of active interfaces selected by the devices at both ends must be consistent, otherwise the link aggregation group cannot be established, so that one end can be the active end, and the other end (passive end) can select the active interface based on the active end.
The main differences between the two link aggregation modes are:In static LACP mode, some links act as backup links;In manual load balancing mode, all members are in the ** state.
2. Data flow control
1. In an aggregation port, all parameters of the member ports must be consistent, including the number of physical ports, transmission rate, duplex mode, and flow control mode. Member ports can be Layer 2 or Layer 3.
2. In order to avoid the situation that the packets are out of order due to the transmission of multiple member ports, the arrival order of the data frame before and after is inconsistent. The eth-trunk uses a flow-by-flow load balancing mechanism to distribute data frames according to different conditions, such as the source MAC address, destination MAC address, source IP address, destination IP address, VLAN, and physical port. The data frames of different results are sent through different member ports, and the data frames of the same results are sent from the same member ports, so as to ensure the accuracy of the packet order. However, this does not guarantee bandwidth utilization.
1. Layer 2 configuration
Run the interface eth-trunk command to configure link aggregation. This command creates an eth-trunk port and enters the eth-trunk port view. trunk 1 is used to uniquely identify an eth-trunk, and the value of this parameter can be any integer between 0 and 63. If the specified eth-trunk port already exists, run the interface eth-trunk command to directly enter the eth-trunk port view.
, configure the eth-trunk port, and pay attention to the following:
1. Only eth-trunk ports that do not contain any member ports can be deleted.
2. When adding an interface to an eth-trunk port, the member port of the Layer 2 eth-trunk port must be a Layer 2 interface, and the member port of the Layer 3 eth-trunk port must be a Layer 3 interface.
3. An eth-trunk port can add up to 8 member ports.
4. The interface added to the eth-trunk port must be a hybrid interface.
5. An eth-trunk port cannot act as a member port of other eth-trunk ports.
6. Only one eth-trunk port can be added to an Ethernet interface. If you add an Ethernet interface to another eth-trunk port, you must delete the Ethernet interface from the current eth-trunk port.
7. The port types of each eth-trunko member must be the same. For example, a fast Ethernet port and a Gigabit Ethernet port cannot be added to the same eth-trunk.
8. Ethernet ports on different interface boards can be added to the same eth-trunk port. If a peer interface is directly connected to a member port of the local eth-trunk port, the peer interface must also add an eth-trunk port. Otherwise, the two ends cannot communicate.
9. If the speed of member ports is different, the interface with the lower rate may be congested and packets may be discarded.
10. After the interface is added to the eth-trunk port, the eth-trunk port learns to Xi the mac address, and the member port no longer learns Xi.
3. LACP is applicable to scenarios
LACP (Link Aggregation Control Protocol) is a protocol used to establish and maintain link aggregation between network devices. It allows devices to merge multiple physical links, providing higher bandwidth and redundancy.
1. In the case of tight bandwidth, logical aggregation can be used to expand the bandwidth to n times of the original link.
2. In the case that a link needs to be dynamically backed up, the link aggregation can be configured to dynamically back up each other between the member ports of the same aggregation group.
LACP Negotiation Mode:
1. After the LACP protocol is started on a dynamic aggregation port, the default management key is zero.
2. After LACP is enabled for a static aggregation port, the management key of the port is the same as the aggregation group ID.
This is the IT information shared this time, and I hope it will be helpful to you after reading this article. Pay attention to Netbox Education***Learn more about IT information!