This MIB modules defines objects that describe common aspects of IP address pools. IP Address Pool Manager ======================= The IP address pool manager consists of the software that maintains IP address pools and supports the following capabilities: - Create an IP address pool group. - Destroy an IP address pool group. - Create an IP address pool and add it to an IP address pool group. - Remove an IP address pool from an IP address pool group and destroy it. - Create a range of IP addresses and add it to an IP address pool. - Remove a range of IP addresses from an IP address pool and destroy it. - Allocate an IP address from an IP address pool. - Return a previously allocated IP address to the IP address pool that it was allocated from. - Create a set of IP prefixes and adding it to an IP address pool. - Remove a set of IP prefixes from an IP address pool and destroy it. - Allocate an IP prefix from an IP address pool. - Return a previously allocated IP prefix to the IP address pool that it was allocated from. IP Address Pool =============== An IP address pool consists of a collection of IP addresses from which a client (e.g., PPP or DHCP) can allocate an IP address for the purpose of assigning it to a remote peer. This collection consists of a one or more range of IP addresses. Observe that human interfaces allow a user to specify ranges of IP addresses using a variety of means to simplify the process. For example, a human interface may simply allow a user to specify a subnet. No matter what abstraction a human interface employs, the end result is always one or more range of IP addresses. Thus, this MIB module abstracts an IP address pool as one or more range of IP addresses. This places the burden on any application employing other abstractions to transform to the abstraction defined by this MIB module. Alternatively, an IP address pool can also consist of a collection of IP prefixes from which a client can allocate an IP prefix for the purpose of assigning it to a remote peer. This collection consists of one or more set of IP prefixes. Observe that the term 'IP prefix' here can refer to an IPv4 subnet or an IPv6 prefix. IP Address Pool Group ===================== An IP address pool group contains the IP address pools belonging to the same administrative domain. Examples of administrative domains include a Virtual Route Forwarding (VRF) instance and a Virtual Private Network (VPN). Observe that the IP addresses contained by the IP address pools in two distinct IP address pool groups may overlap. IP Address Pool Threshold Monitoring ==================================== An IP address pool manager maintains a number of gauges for the purpose of monitoring the number of allocated IP addresses. We refer to these gauges as 'in-use gauges'. Each in-use gauge has a corresponding state that can have one of two values: 1) Off The IP address pool manager monitors the number of allocated addresses or prefixes. If this value is greater than or equal to the configured rising threshold and the previous value was less than the same rising threshold, then the IP address manager transitions the state to 'On'. 2) On The IP address pool manager monitors the number of allocated addresses or prefixes. If the value is less than or equal to the configured falling threshold and the previous value was greater than the same falling threshold, then the IP address manager transitions the state to 'Off'. Observe that while the values of the configured rising and falling thresholds may be the same, this may result in undesirable behavior (i.e., the IP address pool manager may generate more threshold crossing notifications than desirable). The IP address pool manager only generates threshold crossing notifications when it transitions the corresponding state of an in-use gauge and the value of ciapSystemNotifyEnable is 'true'. The IP address pool manager may maintain in-use gauges for the following: - A range of IP addresses comprising an IP address pool - A set of IP prefixes comprising an IP address pool - An IP address pool - An IP address pool group Observe that the IP address pool manager must initialize the state of each in-use gauge to 'Off' for threshold monitoring to operate in the prescribed manner.