This MIB module extends the IETF draft NAT MIB available at http://tools.ietf.org/html/draft-ietf-behave-nat-mib-11 The extensions are intended to address the needs of the Carrier Grade NAT (CGN), also known as Large Scale NAT (LSN). GLOSSARY ========== Address mapping - is used to refer to association between a private IP to public IP (in case of NAT44 and DS Lite) or source IPv6 address to IPv4 address in case of NAT64 stateful application. Mapping - A mapping used to refer to a NAT translation record. It is a record held in memory that maps a private IP address and port to a public IP address and port. Subscriber - A subscriber is a record held in memory that provides IP address and other details of an end user device which has one or more mappings. Session - A session is a record maintained in memory that identifies a flow. The flow is uniquely identified by the source IPv4/IPv6 address, source port, translated IP address, translated source port, destination IPv4/IPv6 address and destination port. In to Out packet - A packet originating from a subscriber, with a private source address (or with an IPv6 address in case of NAT64), destined to a host with a public IP address. This packet needs NAT (or NAPT) service. Out to In packet - A packet originating from a host on the public Internet (or any host with a routable/public) source address, whose destination address is a mapped (translated) IP address. This packet needs reverse-NAT. Bulk port allocation - A NAT instance can be configured pre-allocate a range of contiguous ports instead of a single port. A mapping log record is created indicating the range of ports allocated to this subscriber. This is done in anticipation that the subscriber is likely to send packets that require more mappings to be created. For the subsequent mapping requests, one of the pre-allocated port is used and no additional log entries need to be created. This is a technique used to reduce the volume of translation record data.