Cisco Systems 3.5 Transaction Data Verification, Transaction Order, Automatic Resynchronization

Page 42

Chapter 4 Understanding Replication

How Replication Works

Transaction Data Verification

When the master prepares a transaction for replication to a slave, the master calculates a 2's complement Cyclic Redundancy Check (CRC) for each element (individual configuration change) in the transaction and for the entire transaction and includes these CRC values in the transmitted transaction. When the slave receives the transaction, the slave calculates a CRC for each transaction element and for the entire transaction and compares its own calculated values with those sent with the message. If a discrepancy occurs from these comparisons, the transaction element or the entire transaction is discarded and a re-transmission of that particular transaction element or the entire transaction is requested by the slave from the master. This process is called automatic resynchronization. (described in more detail below)

Transaction Order

When the master prepares a transaction for replication, it assigns the transaction a unique transaction number. This number is used to ensure the transactions are processed by the slave in exactly the same order as they were processed on the master. Transactions are order dependent. Since the functionality of Access Registrar's configuration replication feature is to maintain identical configurations between master and slave, if transaction order were not retained, master and slave would not contain identical configurations. Consider where two transactions modify the same thing (a defined client's IP address for example). If the first transaction was a mistake and the second was the desired result, the client config on the master would contain the second setting; however, if the transactions were processed in the reverse order on the slave, the client config on the slave would contain the mistaken IP Address. This example illustrates the critical need for transaction ordering to ensure data integrity.

Automatic Resynchronization

Automatic Resynchronization is the most significant feature with respect to data integrity. This feature ensures the configurations on both the master and slave are identical. If they are not, this feature automatically corrects the problem.

When the master and slave start-up, they determine the transaction number of the last replication transaction from their respective replication archives. The master immediately begins periodic transmission of a TransactionSync message to the slave. This message informs the slave of the transaction number of the transaction that the master last replicated.

If the transaction number in the TransactionSync message does not match the transaction number of the last received transaction in the slave's archive, then the slave will request resynchronization from the master. The resynchronization request sent by the slave will include the slave's last received transaction number.

The master will respond by retransmitting each transaction since the last transaction number indicated by the slave in the resynchronization request. The master obtains these transactions from its replication archive.

Should the slave's last received transaction number be less than the lowest transaction number in the master's replication archive, then automatic resynchronization cannot occur as the master's replication archive does not contain enough history to synchronize the slave. In this case, the slave must be resynchronized with a full-resynchronization.

Cisco Access Registrar 3.5 Concepts and Reference Guide

4-4

OL-2683-02

 

 

Page 41 Page 43
Image 42
Page 41 Page 43
Contents Cisco Access Registrar 3.5 Concepts and Reference Guide Corporate HeadquartersCisco Access Registrar 3.5 Concepts and Reference Guide N T E N T S IiiSession-Service Service Step and Radius-Session Service Replication’s Impact on Request Processing IPAddress Port Understanding Snmp Accounting Start Data Flow ViiViii Obtaining Documentation World Wide WebDocumentation Feedback Obtaining Technical AssistanceOrdering Documentation Cisco.comContacting TAC by Using the Cisco TAC Website Technical Assistance CenterContacting TAC by Telephone Xii Overview Radius ProtocolSteps to Connection Packet Exchange Between User, NAS, and RadiusPacket Contents Types of Radius MessagesProxy Servers Attribute DictionaryBasic Authentication and Authorization Proxying to an Ldap Server for AuthenticationOverview Basic Authentication and Authorization Understanding Cisco Access Registrar Cisco Access Registrar HierarchyProfiles ServicesUserLists and Groups ScriptsSession Management Using Resource Managers Cisco AR Directory Structure Program FlowSubdirectory Description Cisco AR Server Action Explanation Scripting PointsClient or NAS Scripting Points Action ExplanationAuthentication and/or Authorization Scripting Points Radius/Advanced/RequireNASsBehindProxyBeInClieSession Management Failover by the NAS and Session ManagementAuthentication/Authorization Scripts Script Processing HierarchyIncoming Scripts Cross Server Session and Resource Management OverviewOutgoing Scripts Session-Service Service Step and Radius-Session Service Configuring a Front Line Cisco Access RegistrarConfigure Central AR OL-2683-02 Using Cisco AR Scripts ACMEOutgoingScriptAltigaIncomingScript ANAAAOutgoing AuthorizeServiceAltigaOutgoingScript AscendIncomingScriptCabletronOutgoing AuthorizeTelnetCabletronIncoming CiscoIncomingExecFilterRule ExecTimeRuleExecDNISRule ExecNASIPRuleParseAAARealm LDAPOutageMapSourceIPAddress ParseAAASRealmParseServiceAndAARealmHints ParseServiceAndAAARealmHintsParseServiceAndAAASRealmHints ParseServiceAndAASRealmHintsParseTranslationGroupsByDNIS ParseServiceHintsParseTranslationGroupsByCLID ParseTranslationGroupsByRealmUSROutgoingScript Understanding Replication Replication OverviewHow Replication Works Replication Data FlowMaster Server Ensuring Data Integrity SecurityReplication Archive Slave ServerTransaction Data Verification Transaction OrderAutomatic Resynchronization Full Resynchronization Replication Configuration SettingsUnderstanding Hot-Configuration Replication’s Impact on Request ProcessingRepTransactionArchiveLimit RepTypeRepTransactionSyncInterval MasterRepSecret RepIPAddressRepPort RepIPMasterName Rep Members SubdirectoryRep Members/Slave1 IPAddressOverview Supported MIBsSnmp Traps RADIUS-AUTH-SERVER-MIBCarServerStop Supported TrapsCarServerStart CarInputQueueFullCarOtherAuthServerNotResponding CarOtherAuthServerRespondingCarOtherAccServerNotResponding CarAccountingLoggingFailure Configuring TrapsCarOtherAccServerResponding Directories SearchedConfiguration File Types Switching Configuration Files in Mid-FileCommunity String OL-2683-02 Prepaid Billing Solution Measurements and Component Actions Configuring Prepaid Billing Generic Call Flow Call Flow DetailsAccess-Request Authentication Attribute Number Attribute Name DescriptionAccess-Accept Authentication Access-Request AuthorizationAccess-Accept Authorization Accounting Start Data FlowAttribute Number Attribute Name Access-Request Quota Depleted Accept-Accept Quota DepletedAccounting Stop Session End Accounting Response Final StatusVendor-Specific Attributes Source VSA Name Type Call Flow DescriptionTotal Volume quota received by Crbprivate O S S a R Y GL-1Scalable wholesale access/open access solution GL-2GL-3 GL-4 GL-5 GL-6 GL-7 GL-8 GL-9 GL-10 Radius IN-1RFC IN-2IN-3 IN-4
Related manuals
Manual 180 pages 47.88 Kb

3.5 specifications

Cisco Systems 3.5 is an advanced version of Cisco's renowned networking and security solutions. This iteration showcases significant enhancements in performance, scalability, and security, making it a preferred choice for enterprises aiming to optimize their network operations and bolster their cybersecurity posture.

One of the main features of Cisco Systems 3.5 is its enhanced network automation capabilities. Automation streamlines network management, allowing organizations to apply consistent policies across their infrastructure while minimizing human error. This version employs advanced algorithms and machine learning to predict and rectify network issues proactively. With automation tools, network administrators can configure, monitor, and troubleshoot their networks with unprecedented efficiency.

Another notable characteristic of Cisco Systems 3.5 is its integration of artificial intelligence and machine learning into networking processes. The incorporation of AI enhances decision-making by analyzing vast amounts of network data, identifying patterns, and offering insights that help ensure optimal performance. This predictive analytics capability allows organizations to predict potential disruptions before they impact operations.

Security is a major focus in Cisco Systems 3.5. The platform introduces advanced threat detection and response systems that utilize deep learning to identify and mitigate emerging threats in real-time. Enhanced encryption protocols ensure that data transmitted over the network remains secure, protecting sensitive information from cyber threats. The integrated security features ensure compliance with various regulatory standards, a crucial requirement for businesses across multiple sectors.

The platforms' support for Software-Defined Networking (SDN) allows for dynamic resource allocation and traffic management. This flexibility enables organizations to adjust their network resources quickly in response to changing demands, leading to improved efficiency and reduced operational costs. Cisco Systems 3.5 also supports multicloud environments, facilitating seamless integration with cloud services such as AWS, Google Cloud, and Microsoft Azure.

Moreover, Cisco Systems 3.5 offers robust telemetry features, providing detailed real-time insights into network performance and health. This data-driven approach allows organizations to make informed decisions regarding capacity planning and resource optimization.

In summary, Cisco Systems 3.5 combines cutting-edge technologies such as AI, machine learning, and SDN to deliver a comprehensive networking solution. With its focus on automation, enhanced security, and multicloud support, this version is well-suited for modern enterprises looking to enhance their network infrastructure and security measures. As organizations continue to evolve in a digital-centric world, Cisco Systems 3.5 stands out as a critical tool to achieve connectivity and security goals effectively.
Top Page Image Contents