s is specified. sysName: The name of the system to identify it in a network. sysLocation: The physical location of the system. sysServices: This is the services offered by the system. A number is used to indicate the functionalities performed (e.g., bridge functions, repeater functions, router functions, etc.). Not all these objects are writable. In the above example sysContact, vsName, and sysLocation are writable while others are read-only. b. Interface Group (2) This group consists of the ifNumber and ifTable, where ifNumber corre- sponds to the number of rows in the ifTable (interface table). Thus ifNumber is a direct indication of the number of entities or interfaces of the system. The if Table has a set of attributes (columns) for each interface associated to the system. Some of these attributes are: ifIndex: This is the index column of the ifTable. ifDescr: This field is used to give a description for the interface. Usually the vendor name and number for the interface is listed in this field. ifType: This is the interface type. It can take values like 15 for FDDI interface, 23 for PPP interface, 32 for Frame Relay interface, and SO on. There are more than 150 different types of interfaces and the type list is maintained by IANA (Internet assigned numbers authority). ifPhysAddress: It corresponds to the interface address and is usually the MAC address. ifAdminStatus: This shows the admin status and is a writable field. ifInErrors/ifOutErrors: This field maintains a count of input (ifInEr- rors)/output (ifOutErrors) errors for the interface. ifInDiscards/ifOutDiscards: This field maintains a count of packets discarded during input (ifInDiscards)/output (ifOutDiscards). ifInOctets/ifOutOctets: This field gives the number of octets received (ifInOctets)/transmitted (ifOutOctets) over the interface. Not all columns in the ifTable are discussed here, but for collecting all possible information about the interface, a complete understanding of ifTable is required. C. AT (Address Translation) Group (3) The address 