Does an AR router that accesses the Internet through multiple upstream interfaces support link aggregation or load balancing


If the multiple upstream interfaces are physical interfaces of the same type (such as GE interface or Eth interface), the bandwidth of these interfaces can be aggregated, which can be deemed equivalent to an Eth-Trunk. The bandwidth of the aggregated interface equals to the sum of the bandwidths of the physical links. For example, If two Eth interfaces are aggregated, the total bandwidth of the aggregated interface is 200 Mbit/s (100 Mbit/s + 100 Mbit/s).
However, if the multiple upstream interfaces are service interfaces, the total bandwidth after aggregation cannot reach the sum of the bandwidths of the interfaces. For example, if two broadband interfaces provided by different vendors, whose bandwidths are 4 Mbit/s and 2 Mbit/s respectively, are aggregated, the rate of the aggregated bandwidth cannot reach 6 Mbit/s. In addition, if the two upstream interfaces use the load balancing ECMP, the rate of the aggregated interface further decreases and may even be lower than the rate of a single upstream interface. The reason is that the interfaces provided by two vendors belong to two different networks, whose packet transmission delays and jitters are different. If the two interfaces are aggregated, the response packets corresponding to TCP link packets (which are used by most services) are disordered, which results in packet reassembly, packet retransmission, or even the disconnection and re-establishment of TCP links. As a result, users cannot access Internet with a high rate or open web pages. In this case, you can take the following measures to try to resolve the problem:
- Use specific routes to distinguish services. Do not use ECMP or use only one upstream interface.
- Use the traffic policy to redirect the next hop to distinguish services, and do not configure load balancing for service.

Other related questions:
Can the AR implement link aggregation or load balancing when multiple AR uplinks are used to access the Internet
If physical interfaces of multiple uplinks are of the same type (GE or Ethernet interfaces), these interfaces can constitute an Eth-Trunk. The bandwidth of the Eth-Trunk is the sum of bandwidths of multiple physical links. For example, the bandwidths of two Ethernet interface are 200 Mbit/s (100 Mbit/s + 100 Mbit/s). If two service interfaces are used, for example, bandwidths of two carriers are leased, among which one is 4 Mbit/s and the other is 2 Mbit/s, 6 Mbit/s bandwidth for Internet access cannot be implemented. If ECMP is configured on the two service interfaces, Internet access through one uplink may be faster than Internet access through the two service interfaces. This is because two carriers use different networks on which the delay and jitter are different. Mis-sequencing of TCP packets (most services use TCP) may occur. As a result, TCP packets are reassembled and retransmitted, or even TCP connections are torn down and reestablished. The Internet access speed is slow and web pages cannot be opened. Use the following methods to solve the problem: -Use specific routes to different services, do not use ECMP, or use only one uplink interface. -Use a traffic policy containing redirection to next hop addresses so that services are not load balanced.

Does an AR support two uplink interfaces in load balancing mode
If an AR has two WAN interfaces configured, the two uplink interfaces work in load balancing mode. 1. Configure two equal-cost static routes. 2. Configure policy-based routing to change the forwarding path of packets.

Does the AR router support intelligent load balancing
The AR router does not support intelligent load balancing.

Does the AR router support web NMS access through an external network?
The AR router supports web NMS access through an external network.

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