374 CHAPTER 16: NETWORK MANAGEMENTTerminology andAcronymsMake sure you are familiar with the following terminology and acronyms,which are commonly used when discussing SNMP operations.SNMP Managersand AgentsAn agent using network elements stores network information about itselfin a Management Information Base (MIB). MIBs specify the variables thatnetwork elements maintain. For example, a variable can contain the datathat records when you last booted the system.SNMP managers are network hosts that use SNMP software to poll thenetwork devices and receive the information stored in them.■ Managers use UDP port 161 by default to send requests to the agent■ Agents use UDP port 162 by default to send replies or messages to themanager.Table 67 SNMP Terminology and AcronymsItem DetailAuthentication Process of ensuring data origin authenticity, specifically thatthe identity of the user is genuine. Also incorporates dataintegrity checks, to ensure data has not been altered ordestroyed in an unauthorized manner.CBC Cipher-Block-Chaining (a method of encoding dataencryptions in a message).HMAC Keyed-Hash Message Authentication Code. Provides messageauthentication through the use of cryptographic hashfunctions.Inform Reliable notification of an SNMPv3 event.Key A value that is used to ensure authenticity or privacy, withoutwhich it is almost impossible to masquerade or eavesdrop.MD5 Message Digest type 5 (a type of hashing function).Notification SNMPv3 event.Privacy The hiding of data from eavesdroppers.SHA Secure Hashing Function (a type of hashing function).Trap SNMPv1 message notifying the manager of a system event.USM User-based Security Model.VACM View-based Access Control Model.MIB Management Information Base.
