1. Check whether the quality of a link is poor. Run the shutdown command on the four outbound interfaces in sequence to test the link quality. The problem persists.
2. Check whether a load balancing problem occurs. Run the ip load-balance hash src-ip command to enable load balancing based on the source IP address. The problem persists.
3. Check whether a packet fragmentation problem occurs. Run the tcp adjust-mss command on VLANIF 10 to set the maximum segment size (MSS) of TCP packets to 1200 bytes. The test result shows that network access and file downloading are still slow.
4. Check whether an STP problem occurs. Run the undo stp enable command in the system view to disable STP. The test result shows that the network access rate is higher but does not meet the customer's bandwidth requirement.
5. The interface of link 1 is on an 8FE1GE card. Check whether packet forwarding on the interface is normal. Run the set workmode lan-card l3centralize command to disable the routing and forwarding function on high-end LAN cards (8FE1GE and 24GE cards). The test result shows that network access and file downloading are normal. The problem is fixed.
You are advised to troubleshoot the problem from the following aspects:
1. Link quality
2. Hash algorithm of links
3. TCP MSS value on an interface
5. Routing and forwarding function of high-end LAN cards (8FE1GE and 24GE cards): Disable the routing and forwarding function on high-end LAN cards so that the router diverts packets received on the cards to the sub-core CPU. The sub-core CPU forwards the packets, improving packet forwarding efficiency.