tmnxCpmProtExcdSapIpTable has a row for each <service ID, SAP, source
IP address> triple that has exceeded the per-source rate limit
configured for the <service ID, SAP> pair. IP-layer per-source rate
limiting is enabled for a <service ID, SAP> pair by setting
TIMETRA-SAP-MIB::sapCpmProtMonitorIP to 'true'.