Congestion control: consider packet type as well as age
Kea has congestion control, that addresses the issue that FIFO handling, when the queue grows too long, will result in replying only after the client has given up waiting and sent a new request. This feature request asks that we consider not only packet age, but also the request type when dealing with a temporary peak load.
When the DHCP service is under heavy load and internal queues are reaching a critical level, it may be desirable to prioritize DHCP-RENEW and DHCP-REBIND packets to ensure continuity of service to already active subscribers. DHCP-DISCOVERS must be handled differently, either by assigning a lower priority or by dropping those packets. In the latter case, clients will initialize their retry mechanism with backoff delay, however this may cause some unwanted effects on the DHCP service if the total number of clients increases.
For DHCP-DISCOVER packets prioritization is preferred over dropping.
(labelled docsis but this is not specific to cable operators.)