Enterprise and Technical Architecture

In layered architecture, each layer communicates with its peer layer on another device. The data unit exchanged between peer layers is called a Protocol Data Unit (PDU). Different layers have different PDU names - segments at transport layer, packets at network layer, frames at data link layer - but collectively they're all PDUs.

IP spoofing involves forging source IP addresses in packets to appear as if they originate from trusted sources. Options A and C describe different attacks (password theft, social engineering), and D describes phishing.

DNS servers map hostnames to IP addresses, so hackers can use DNS data to discover a host's network location. TCP/IP, Telnet, and SSL servers don't provide this network mapping information.

A hot spare is a standby drive that automatically replaces a failed drive in a RAID array. Hot swap is manual replacement, cold swap requires system shutdown, and none is incorrect.

Clustering allows multiple servers to work together as a single system, providing failover capability so that if one server fails, others continue handling requests. RAID only protects data at the storage level, while backups are for recovery after failure, not continuous availability.

Directory services (like LDAP or Active Directory) serve as the centralized repository storing user IDs, credentials, and profile information. Authentication services validate credentials against this directory, but the directory itself holds the identity data. Authorization services determine permissions, and personalization services customize user experience - neither act as the primary repository.

In technology lifecycle management, 'Contained' represents technologies that are currently deployed and require ongoing maintenance support, but are not strategic or recommended for new implementations. This category helps organizations manage their existing technology footprint while limiting further investment in non-strategic components.

WSDL (Web Services Description Language) is an XML-based specification that describes how to access a web service. It defines the service endpoint, operations, message formats, and protocols. UDDI is for discovery/registry, SOAP is for messaging, and ESB is an integration architecture pattern - none of these describe the access interface itself.

UDDI (Universal Description, Discovery, and Integration) provides a registry-based mechanism for publishing and discovering web services. It allows organizations to list their services and enables clients to search for available services by type, category, or other criteria. WSDL describes interfaces, SOAP handles messaging, and ESB is an integration pattern.

RMI (Remote Method Invocation) is a Java-specific remote communication technology that uses binary serialization, not XML. It's tightly coupled to the Java platform. In contrast, UDDI, WSDL, and SOAP are all XML-based specifications that form the core of web services, providing platform-neutral interoperability through XML messaging.

In technology lifecycle management, 'Declining' identifies technologies approaching end-of-life that require migration planning. These systems remain operational but represent increasing technical and business risk. Organizations should plan to transition away from declining components to more modern, supported alternatives.

Selecting components from the reference architecture provides strategic advantages beyond meeting immediate requirements: consistency, maintainability, supportability, and alignment with organizational standards. While functional requirements are necessary, they're insufficient alone - the reference architecture embodies enterprise best practices and supports long-term architectural evolution.

Provisioning services automate the entire user account lifecycle across multiple backend systems - creating accounts when users join, modifying permissions as roles change, disabling accounts when access should be revoked, and deleting them after departure. Access Management (A) controls what users CAN access, not account creation. Identity Management (C) is the broader governance framework. User Management (D) typically refers to manual administration tasks.

Infrastructure applications provide foundational services that support organizational operations. VPNs enable secure remote connectivity, System/Network Management tools monitor and maintain IT health, email services handle communication, and office software suites support productivity. All represent infrastructure-layer applications that multiple users or systems depend on.

The TOGAF Technical Reference Model defines a structured architecture with four main categories: applications (software), application platform (middleware/runtime), communication infrastructure (networking), and the application platform interface between them. The human-machine interface (HCI/UI) is a separate cross-cutting concern, not a formal layer within the TRM structure.

Gap analysis is the formal technique used to compare baseline (current state) and target (future state) architectures. It identifies what technology capabilities exist today, what's needed tomorrow, and the deltas that must be addressed. Requirements analysis happens earlier. Impact analysis assesses change consequences. Architecture audits review compliance.

TOGAF's four core architecture domains are Business Architecture (process/organization), Data Architecture (information structures), Application Architecture (software portfolio), and Technology Architecture (hardware/infrastructure). Systems Architecture is NOT a separate TOGAF domain - it's a subset or alternative term that falls within Technology Architecture, not a pillar alongside the others.

TOGAF is specifically designed for Enterprise IT Architecture - organization-wide technology strategy and planning across business, data, applications, and technology. It's too high-level for software architecture (individual systems). It doesn't address human/organizational design directly. BPM for SOA is a methodology, not an architecture planning level.

Technical architecture encompasses hardware components (A), software applications running on them (C), infrastructure services provided to applications (D), and protocols for connectivity (E). Option B is the exception - while technical architecture considers these interactions, 'interaction between application packages' in terms of functional coverage is more properly an Application Architecture concern (functional fit/gaps), not Technical Architecture.