Inventory audit

RFC 2697 and RFC 2698 describe three-color policers, meaning that the packets can be colored to three separate values to indicate whether they conform to, exceed, or violate the policing conditions. The single-rate three-color marker and the two-rate three-color marker initially were implemented (in IOS Software Releases 12.2[2]T and 12.2[4]T, respectively) to operate in color-blind mode. This means that the policer assumes that the packet stream previously was uncolored. The RFCs also define a color-aware mode, which means that the policer assumes that some preceding entity already has colored the packet stream. At the time of this writing, the color-aware mode is available only in IOS Software Release 12.0.26S; it is not yet available in any 12.2T release.

Most networks contain a wide array of interfaces with inventory audit. If absolute bandwidth rates are used in policing policies, the policy must be re-entered for each different interface size. This reduces policy modularity and makes policy management more cumbersome across the enterprise. It often is desirable to have an overall network policy in which, for example, FTP traffic is not to exceed 10 percent of the bandwidth on any interfaceregardless of absolute speed. This can be achieved using percentages in the policing statements. Thus, a single policy can be reused across many interfaces in the network