First step would be to narrow down the problem to one or more of the following areas: -
RF Network
IP Network
Backhaul.
RF Spectrum sweep at the CCU and, a close look at the Signal-to-Noise (RNA) and Signal Quality (SQ) values displayed at the “Air Table” will help to identify if there is any RF interference issue. Any system wide degradation of these values indicates possible RF interference issue. (Reference RSSI-Data r1)
If CCU is seeing another CAP site operating on the exact same channel frequency, this could result degradation of system wide performance. This can be identified by the “purple dot” on the spectrum sweep. Also, this can be confirmed by looking at the “rxPktNoMatch” parameter (CLI command <stats mac>). The climbing value confirms that the CCU is seeing another CCU on exactly the same frequency. The solution is to change the channel to a different channel or offset the channel frequency by +/-200KHz. (will help if the interfering signal level is low, typically below –95 dBm).
If RF is eliminated as a possible source of degradation, should look at the network statistics for IP network issues. These include “Stats”, “Syslog Analysis”, “Air Table Analysis” and the “Routing Table”. Key indications to watch are excessive broadcasts; excessive discard of Tx. Packets, high Ethernet interrupts, dominating smaller packets and “Radio Meter” violations. These indicators (with RF eliminated as a factor) point to network related issues, such as Denial Of Service Attack, Broadcast Storms, Viruses, etc. Also, indication of typical heavy virus type activities that are heavy on resources (rather than bandwidth) are higher TxDiscards, Receiving (CCU) Smaller Packets from EUMs at much higher rates compare to the packet flow of the other direction, channel efficiency (syslog analysis) showing very smaller packets dominating the air-link and high percentage of broadcasts (over 8%).
Please refer to the attached flow chart FC003. Also, TB129 and TB134 are relevant Technical
RSSI-Data
Cap Site_Slow_Internet_FC003
TB0134-NachiWorm_BlasterWorm_Mitigation_r2
