ISP路由器Wi-Fi运行数天后出现响应迟缓问题的原因咨询

Hey there, let's dig into this issue you're facing—it's a tricky one but there are a few likely culprits based on your setup details:

• NAT/DHCP资源耗尽或内存泄漏
  Most ISP-provided ONT+Router combo units have pretty underwhelming hardware, especially lower-end models. When it's handling all core networking tasks (NAT session management, DHCP lease assignments, plus Wi-Fi client connections) nonstop for days, it can run into memory leaks or resource exhaustion. Ping tests only check basic connectivity and latency, so they'll still look fine—but loading websites or using apps requires setting up new NAT sessions or processing queued requests, which gets bogged down when the router's resources are stretched thin. When you use your TP-Link as the main router (taking over NAT/DHCP), the ISP device only acts as a simple pass-through, so it never hits that bottleneck.

• Wi-Fi客户端管理过载
  The Wi-Fi chip or firmware on your ISP's router might not handle long-term, multi-client connections well. When your TP-Link is in Access Point mode, all client connections are still managed by the ISP router. Over a few days, accumulated client connection logs, stale sessions, or unoptimized client handling can slow down the Wi-Fi module's ability to process requests. Your TP-Link, on the other hand, likely has better firmware optimization for client management, so it stays snappy when it's in charge.

• Buggy ISP固件后台进程
  Many ISPs load custom firmware onto their routers with hidden features like remote management, network monitoring, or even ad-blocking. These processes can have bugs that cause them to hog CPU or memory over time. Ethernet traffic often gets higher priority in router firmware, so it's less affected—but Wi-Fi traffic takes a hit as the router's resources get tied up by these misbehaving background tasks.

• DHCP地址池耗尽或租期冲突
  If your ISP router's DHCP address pool is small, after a few days all available IP addresses might be assigned. When clients try to renew their leases or new devices connect, they'll have to wait longer for an available address, which makes websites and apps feel sluggish. Your TP-Link router probably has a larger default address pool or better lease management, so this doesn't happen when it's handling DHCP.

Quick troubleshooting steps to confirm: #

• Try restarting your ISP's ONT+Router combo after it gets sluggish—if the Wi-Fi snaps back to normal, that's a strong sign of resource exhaustion or firmware bugs.
• Log into your ISP router's admin interface and check system stats (CPU usage, memory usage, number of active NAT sessions) right after a restart, then check again after a few days. A big spike in any of these points to the root cause.
• If your ISP allows it, switch the combo unit to bridge mode so your TP-Link handles all routing, NAT, and DHCP. This completely bypasses the ISP router's performance limitations.

备注：内容来源于stack exchange，提问作者Zune