All about wireless networking and NMS/EMS

Event: An  event  is an occurrence or detection of some condition in or around the network. An event is a distinct incident that occurs at a specific point in time. Examples of events include: ·         Port status change ·         Device reset ·         Device becomes unreachable by the management station An event can also result from: ·         A fault that is an error, failure, or exceptional condition in the network. For example, when a device becomes unreachable, an unreachable event is triggered. ·         A fault clearing. For example, when a device state changes from unreachable to reachable, a reachable event is triggered. Alarm generated by NE and NMS: ·         By receiving no...

MySQL replication is a process that enables data from one MySQL database server (the master) to be copied automatically to one or more MySQL database servers (the slaves). It is usually used to spread read access on multiple servers for scalability, although it can also be used for other purposes such as for failover, or analyzing data on the slave in order not to overload the master. At first, replication was based on propagation of SQL statements from the master server to the slave server. This replication format is called statement-based replication (SBR) and is default in older versions of MySQL (<= 5.1.4). Just as a note that in later versions of MySQL, especially with the  Innodb Plugin , you NEED to run your  transaction_isolation  with REPEATABLE-READ. The newer replication type is row-based replication (RBR), which logs changes in individual table rows to the binary log. Basically, logging the actual change and not the ...

MySQL is an open source relational database management system ( RDBMS ) based on Structured Query Language ( SQL ).  A database is a separate application that stores a collection of data. Each database has one or more distinct APIs for creating, accessing, managing, searching and replicating the data it holds. Other kinds of data stores can also be used, such as files on the file system or large hash tables in memory but data fetching and writing would not be so fast and easy with those type of systems. Nowadays, we use relational database management systems (RDBMS) to store and manage huge volume of data. This is called relational database because all the data is stored into different tables and relations are established using primary keys or other keys known as  Foreign Keys . MySQL is released under an open-source license. So you have nothing to pay to use it. MySQL is customizable. The open-source GPL license allows programmers to modify the MySQL...

SMI Stands for Structure of Management Information, which defines the rules for describing management information, using Abstract Syntax Notation One (ASN.1). Structure of Management Information (SMI) , an adapted subset of  ASN.1 , operates in  Simple Network Management Protocol  (SNMP) to define sets ("modules") of related managed objects in a  Management Information Base  (MIB). SMI subdivides into three parts: module definitions, object definitions, and notification definitions. Different b/w SMIv1 & V2 is, V2 support counter64, Similar to Counter32, except that the range is now (0 to 2e64 -1). This type may only be used when a 32-bit counter rollover could occur in less than an hour. Otherwise, the Counter32 type must be used. It may only be used when backwards compatibility is not a requirement because this type is not available in SNMPv1. Abstract Syntax Notation One  ( ASN.1 ) is an  interface description language  for d...

SNMPv1 Message Formats SNMPv1 messages contain two parts: a message header and a protocol data unit (PDU). Figure: An SNVPv1 Message Consists of a Header and a PDU  illustrates the basic format of an SNMPv1 message. Figure: An SNVPv1 Message Consists of a Header and a PDU SNMPv1 Message Header SNMPv1 message headers contain two fields: Version Number and Community Name. The following descriptions summarize these fields: §   Version number  - Specifies the version of SNMP used. §   Community name  - Defines an access environment for a group of NMSs. NMSs within the community are said to exist within the same administrative domain. Community names serve as a weak form of authentication because devices that do not know the proper community name are precluded from SNMP operations. SNMPv1 Protocol Data Unit SNMPv1 PDUs contain a specific command (Get, Set, and so on) and operands that indicate the object instances involved in the transactio...

SNMPv1 Only form of security used in  SNMPv1  is community names. Community names are similar to passwords. The concept behind using community name is that all the managed devices in an SNMP network which are being managed by a network manager are considered to be in a community and a specific name i.e. community name  can be assigned to it. While creating the SNMP PDU, this community name is set in the message header and any message received with the wrong value of the community name would be rejected by the receiver. The community name set in the message header is in the form of plain text. the NMS issues a request, and managed devices return responses. Agents use the Trap operation to asynchronously inform the NMS of a significant event. Disadvantage: The biggest downsides are that it does not support 64 bit counters, only 32 bit counters, and that it has little security. A community string sent in plaintext SNMP PDU’s:   Get Request, GetNext Request, ...