Advanced Hardware Features
Call rate limiting feature
The goal of this feature is to continue processing ongoing calls normally in the event of call bursts from the network. Overloaded calls will be dropped with congestion. This will prevent overloading the system, continue normal call processing and keep the system stable. These call bursts are more likely from a SIP network, where calls can come from many different devices. Calls per second in the system are calculated every second. If the call rate specified in the configuration is lower than this value, the temporary call buffer will be used. To allow for temporary call bursts, temporary call buffers are created ("call buckets"). If this temporary call buffer is emptied, the calls will be instantly dropped with error code congestion (SS7/ISDN: 42, SIP: 503, CAS: back to Idle state). There are temporary call buffers for each signaling interface (SS7, ISDN, CAS and SIP), for overall calls in the system, and per Network Access Point (NAP). Once incoming calls are accepted (not rate limited), the system will always allow the outgoing call to be executed. Dropped calls due to congestion are showed in the CDRs, as well as traces in the logs (specify which).
Configuration:
1) Overall call rate limitations on SS7/ISDN/CAS/SIP stacks
Hardware -> TB00xxxx [Edit] -> Call Rate Limiting
- Maximum calls per second: If the call rate is higher than this value on this signaling interface (or overall), the call burst buffer will be used.
- Maximum call bursts: If this temporary call buffer is emptied, the calls will be instantly dropped with error code congestion (SS7/ISDN: 42, SIP: 503, CAS: back to Idle state).
2) Call rate limitation per NAP, SS7/ISDN/CAS/SIP
NAP -> NAP_xxxx [Edit] -> Calls Rate Limiting
- Maximum calls per second
- Maximum Call bursts
- Maximum simultaneous incoming calls: Limits the total number of incoming calls on this NAP to this value
- Maximum simultaneous outgoing calls: Limits the total number of outgoing calls from this NAP to this value
- Maximum simultaneous total calls: Limits the total number of calls on this NAP (should be set only for SIP NAPs)
