■With the development of service, when a single link can not meet the needs of the service, how to ensure the reasonable distribution of traffic by adopting different operators' multi-link and multi-link with the same operator?

■P2P and other non-critical traffic affect the normal transmission of traffic, what should be done?

■When the network develops to multi-region and multi-outlet, for example, there are different network exits between campus, office district and family area, how to realize the inter-exit scheduling of different places?

Making traffic "go the right way, get it right" is the key to solving the problem. "Link load balancing solution", which is provided by long-term accumulation in the field of delivery, not only realizes network layer outbound and inbound two-way load balancing, but also realizes intelligent routing based on application layer protocol. And when the user network develops to multi-destination and multi-outlet, it provides wide-area multi-outlet scheduling capability, and realizes the balanced scheduling of off-site traffic.

■At the exit, the link between the same operator and the same operator has the same resources. Load balancing needs to coordinate the traffic between multiple links and make full use of the link resources.

For example, when a user has both 600m telecommunications and 400m telecommunications links, as shown in figure 1, ADX3000, a DPtech application delivery product, can automatically distribute traffic according to network bandwidth ratio, and distribute network traffic according to 6:4 scale. In addition to static scheduling based on the above situation, ADX3000 can actively detect the delay and packet loss rate of the link based on the link quality / state, and calculate the average delay and packet loss rate of the link. When the delay or packet loss rate of a link is found to be too large, the device will judge the failure of the link and schedule the traffic to other normal links to ensure the user's Internet experience.

Figure 1 routing between links of the same operator

■Link selection between different operators at the exit

The resources of different operators have their own strong points. The general users will choose to buy a different operator link to protect the Internet experience, but how to make good use of the links of different operators has become a problem to be solved.

Intelligent route selection to improve bandwidth utilization

For the insiders to select reasonable operators' exits on demand at the network exit, through the techniques of static table item matching and dynamic link detection, the multi-link states can be detected and monitored in real time. Ensure that traffic is distributed to different operators in the most reasonable and fast way to achieve efficient service transmission.

When both telecom and Unicom operators link at the exit of the network, ADX3000 matches the destination IP address according to the built-in operator address table, and dispatches the traffic of the destination address as telecom IP to the telecommunication link. The destination address is to schedule the IP traffic to the Unicom link to avoid cross-operator access and to ensure the traffic flow to the corresponding operator link.

ADX3000 supports dynamic link detection technology. The device will actively detect the delay and packet loss rate of the link. When the detection result exceeds the configured threshold, the device will determine the sub-link failure and schedule the traffic to other links. Traffic will not continue to be scheduled to this link until the link has returned to normal.

When both operator links have related resources, ADX3000 can select less loaded links for intranet users for resource access. For example, devices schedule DNS parsing requests from intranet users to less loaded telecommunication links. Normally, the telecom DNS server returns the IP address of the telecommunication resource, and then the ADX3000 dispatches the resource access request to the telecommunication link, and the access of the intranet user gets better Internet speed. As shown in figure 2, when the intranet accesses the external network, The application delivery device ADX3000 carries on the dynamic scheduling according to the abundant scheduling algorithm, maximizes the utilization network resources.

Figure 2 outbound routing between links between different operators

■Inbound intelligent scheduling, improve access speed when the user has server resources, A domain name will release multiple operators'IP addresses and ADX3000 devices will have the IP address resolution right to issue domain names.

 When external network users access server resources, ADX3000 will return the corresponding server public network IP address according to the external network users' access to the source IP belonging to the operator. In order to avoid cross-operator access, achieve intelligent DNSs, enhance the external network user access effect. And ADX3000 has a fine to municipal level operator address library, On the basis of distinguishing the operators, we can make more detailed traffic scheduling according to the access source IP of different cities. For example, we can schedule the access source IP from one city to the telecommunication link, and the access source IP from other cities to the Unicom link. As shown in figure 3, broadband telecom users return to the external service address of telecom operators through the public network access server resource (ADX3000) to avoid cross-operator access and enhance user access experience.

Figure 3 inbound routing between different operators

■Application layer Traffic scheduling to ensure critical Services

The traditional load balancing methods are based on the network layer to schedule ADX3000, combining the application layer protocol identification technology and routing selection, can achieve the application layer traffic on demand scheduling. Using multiple links provided by operators and allocating resources rationally through intelligent routing in the application layer, P2P HTTP, network games and other applications can be towed to different links to achieve intelligent traffic scheduling in the application layer.

■Wide-area multi-outlet, off-site bandwidth balanced utilization

With the development of user network, when establishing multi-location network exit, sharing network exit among different regions can maximize the utilization of bandwidth. ADX3000's original wide-area virtualization technology can smoothly support multi-location multi-export unified scheduling. As shown in figure 4, when the network exit bandwidth of A is insufficient, the ADX3000 can schedule the access requests of the users of A to the outlet of the B ground network, as shown in figure 4, when the wide area multi-outlet link resources are integrated into one, the ADX3000 can be used to schedule the Internet access requests of the users of the territory A to the outlet of the B ground network. To ensure that users experience the normal Internet access, improve the utilization of bandwidth.

Fig. 4 Wide-area multi-exit flow scheduling

On the operation and maintenance side, ADX3000 supports the function of warning the link abnormal state. By configuring the threshold of packet loss and delay, the operator can be alerted when the link is congested, the flow suddenly drops and the fault occurs. So that the operation and maintenance personnel in the first time to pay attention to the alarm and processing.

In the process of user's exit growth, from single link to multiple ports, Deeptech Link load balancing solution can provide continuous link optimization services. It helps users to schedule network traffic on demand, realizes intelligent traction and optimization management of traffic flow, and further improves network resource utilization and service application efficiency.