National standard GB/T 28181 cascade: key points for docking between upper and lower platforms
What scenarios require cascading
When higher-level units (public security, urban management, group headquarters) require the lower-level systems to be connected to the unified platform, Usually GB/T 28181 is adopted. Its value lies in: as long as equipment from different manufacturers comply with national standards, They can be interconnected through unified signaling without having to adapt private protocols for each manufacturer.
Key concepts
| Concept | Explanation |
|---|---|
| SIP domain | The upper and lower levels each have a domain number, which is used for routing during registration |
| Equipment code | 20-digit code, including center code, industry code, type, serial number |
| Registration | Subordinates register to superiors, carrying authentication information |
| Heartbeat | Periodic keep-alive, timeout superior decision offline |
| Directory push | The subordinate pushes the device list to the superior |
Coding planning should be determined before construction
Do not change the 20-bit device code once assigned - if the code already recorded by the upper-level platform is changed, "Two records appear in the same video" or "Old records cannot be retrieved" will appear. It is recommended to generate it according to the rule of "area + building + floor + serial number" and write the completion data.
Common reasons for docking failure
- Registration failure: The domain number or authentication password is inconsistent, which accounts for the vast majority.
- Can register but cannot get the flow: The UDP port range is not open, or the lower level does not enable "passive flow collection".
- Screen lag: The number of simultaneous channels accessed by the upper level exceeds the uplink bandwidth of the lower level.
- The directory is empty: The subordinate has not pushed the directory, or the pushed encoding does not meet the requirements of the superior.
- Frequent online and offline: The heartbeat cycle setting does not match the superior timeout time.
Joint debugging suggestions
First connect one channel and then batch: select one camera and confirm that registration, directory, streaming, and PTZ control are all normal. Then access in batches. Problems that arise when batching tend to be bandwidth or encoding planning issues, not the protocol itself.