What is a Network Source of Truth (NSoT)?

A Network Source of Truth (NSoT) refers to a central, authoritative data repository or system that holds the most accurate and up-to-date information about a network’s structure, configuration, devices, and related assets. It serves as the definitive reference point for all network-related data and is used to ensure consistency, accuracy, and reliability across different systems and platforms within an organization’s network infrastructure.

Key Components of a Network Source of Truth:

1. Network Topology: A detailed map or model of the network, showing how network resources and devices like routers, switches, firewalls, servers, and endpoints are connected.
2. Device Inventory: A comprehensive list of all network devices and their configurations, firmware versions, and statuses. This includes network hardware and virtual devices.
3. Configuration Data: The specific data and metadata related to settings or configurations applied to each network device, such as IP addresses, VLAN settings, routing protocols, and security configurations.
4. Network Policies: Definitions of access control lists (ACLs), firewall rules, Quality of Service (QoS) settings, and other policies that govern how data flows through the network.
5. Historical Data and Logs: An archive of past configurations, changes, and event logs that help track and audit the history of network setups and incidents.

Importance of an Effective Network Source of Truth:

1. Visibility : A Network Source of Truth acts as a single pane of glass offering unified visibility across cloud and on-premises environments
2. Consistency: A single source ensures that all teams (network, security, DevOps, etc.) are working from the same structured and reconciled data over time, reducing the risk of misconfigurations or discrepancies across systems.
3. Automation: An NSoT enables automated network management and orchestration by providing a reliable, open baseline from which systems can be dynamically integrated using APIs to query relevant data back and forth. API access from external tools allows events to be forwarded upon change towards tools for automated updates.
4. Troubleshooting: A clear and accurate record of the network’s configuration makes it easier to diagnose problems, track changes, and understand the impact of network incidents.
5. Compliance and Auditing: For organizations that need to adhere to industry regulations (e.g. NIS2, DORA, HIPAA, GDPR, PCI-DSS), having a consistent, accurate network configuration record helps with audits and ensures compliance.
6. Change Management: By using a network source of truth, it’s easier to identify inconsistencies between the intended and actual state of networks and manage and track changes, simplifying network validation and ensuring that any modifications to the network are well-documented and can be reverted if needed.

Example Use Cases for a NSoT:

• Network Provisioning: Network source of truth makes it possible to expose relevant data to push configurations, provision VMs, applications, or devices, , and ensure every object is aligned with the intended setup.
• Network Monitoring: Monitoring systems can use the source of truth to compare actual network states with expected configurations, check the health of network devices, and trigger alerts when discrepancies occur. 
• Network Security: In a security context, the source of truth helps maintain up-to-date firewall rules, access control lists, and device health status, aiding in proactive security posture management.

Challenges:

• Data Integrity: Ensuring that the network source of truth is kept consistent, accurate, and up-to-date across different teams and tools can be difficult.
• Integration: The source of truth often needs to integrate with a variety of network management and monitoring tools, which can be a daunted task and sometimes lead to synchronization issues.
• Scalability: As networks grow in complexity (e.g. with hybrid or multi-cloud environments), maintaining a single source of truth can become increasingly challenging across environments.

How DDI Creates and Uses a NSoT

A DDI solution (DNS, DHCP, and IPAM) can create and maintain a Network Source of Truth (NSoT) by centralizing and managing the core network data and metadata related to IP addressing, name resolution, IP address assignment, and VLANs/VxLANs. An advanced DDI solution can provide an extended NSoT that also adds users, applications, devices, and other objects across on-premises and the clouds in addition to IP-related data. Let’s break down how a DDI solution contributes to building a robust, open, and effective Network Source of Truth:

1. Centralizing Critical Network & Cloud Data and Metadata

A DDI solution consolidates three key components of network management – DNS (Domain Name System), DHCP (Dynamic Host Configuration Protocol), and IPAM (IP Address Management) – into one unified platform. Each of these components contains essential data about how devices communicate on the network and how they are addressed:

• DNS: Resolves human-readable domain names into machine-readable IP addresses (e.g. translating www.example.com into an IP address like 192.168.1.10).
• DHCP: Dynamically assigns IP addresses to devices when they connect to the network, managing IP address leases and associated metadata (e.g. which device is using which IP address).
• IPAM: Tracks and manages the entire IP address space, including static and dynamic allocations, ensuring efficient use and organization of IP address ranges.

By integrating these functions into a single DDI solution, the solution creates a centralized repository of critical network information. This centralization means that the DDI solution, and in particular the IPAM, acts as the authoritative source of truth for network configuration and data, making it easier to manage and update all components in one place. This data can be enriched with VLANs/VxLANs, user identities, applications, network devices, and other objects as well as valuable metadata such as location, usage, business unit, external relationships with other repositories, deployment status, dates… to provide an extended NSoT across on-premises and multicloud environments for a single pane of glass visibility.

2. Ensuring Consistency Across the Network

The NSoT must reflect the most accurate and up-to-date state of the network at all times. DDI ensures consistency leveraging built-in consistency checks and network discovery capabilities across several key areas:

• IP Address Assignment: With DHCP and IPAM, the DDI solution ensures that IP addresses are properly managed and assigned, preventing duplication or conflicts. The NSoT will always have the most current list of which devices are using which IP addresses.
• DNS Records: Changes to the network (e.g. devices being assigned new IP addresses) automatically trigger updates to DNS records. As the DDI solution integrates DHCP and DNS, it ensures that when an IP address changes, the associated DNS record is updated seamlessly in the NSoT, providing a consistent mapping of hostnames to IP addresses.
• Object Tracking: The DDI system provides real-time visibility into which objects are active on the network and what IP addresses they have been assigned through discovery tools. This helps ensure that the NSoT remains accurate and that every network object, including devices, applications, or VMs, can be traced back to a valid IP address, hostname, or DNS entry.

3. Real-Time Updates and Automation

A DDI solution automates many aspects of network management, ensuring that the NSoT is always up-to-date. This includes:

• Automated IP Allocation: As devices join the network and request IP addresses via DHCP, the DDI solution dynamically allocates and tracks IPs. The IPAM system immediately updates the NSoT with the allocation and ensures that IP addresses are efficiently utilized without conflicts or human errors.
• Dynamic DNS Updates: When a DHCP lease is assigned to a device, the DNS system can be automatically updated to reflect the device’s hostname and its newly assigned IP address. This helps keep the NSoT synchronized, ensuring the proper association between IPs, hostnames, and devices.
• IP Address Management: IPAM systems track the entire address space (e.g. subnets, VLANs, IP ranges) and ensure that available IPs are efficiently distributed. The real-time management and assignment of IP addresses are reflected in the NSoT, which helps network administrators avoid over-allocating IP ranges and ensures that all addresses are accounted for.
• Automated IPAM Data Reconciliation:  An advanced DDI solution provides automated data comparison across discovery tools and IPAM to easily spot any inconsistencies such as missing IP addresses or different MAC addresses. It will also enable single or multiple remediation actions to reconcile data, improving NSoT data quality.

Enriching DDI with built-in asset discovery tools and APIs ensures consistency and accuracy across hybrid multicloud networks, creating a Network Automation Hub that enables effective end-to-end automation and management of the infrastructure. 

4. Tracking Changes and History

A DDI solution helps maintain an accurate and comprehensive history of network configurations, including:

• DNS Changes: Each user action (e.g. creating, updating, or deleting entries) can be logged and stored, allowing administrators to track modifications over time.
• DHCP Leases: DHCP leases are logged with details about which device was assigned which IP address and when. If an IP address is released, the system logs that event and frees up the address.
• IP Address Usage: The IPAM component tracks historical IP address allocations, including which devices have used which IP address over time. This provides administrators with visibility into IP address usage patterns and allows for more efficient planning of IP space.

This historical tracking ensures that the NSoT reflects not just the current network state but also the intended network state, including a historical record of configurations, which is critical for troubleshooting, auditing, and compliance purposes.

5. Visibility and Reporting

The DDI solution provides visibility into the entire network infrastructure, which feeds directly into the Network Source of Truth:

• IP Address Space Usage: Administrators can see at a glance how IP addresses are allocated and whether any address ranges are running out of space. IPAM reporting tools provide this insight into the NSoT.
• DNS Lookup: The system provides full visibility of all DNS records, including how they are resolving, and how devices are interacting with each other via DNS. This can be critical for diagnosing network issues or identifying potential misconfigurations.
• Network Changes: The DDI solution gives an overview of network changes, such as devices joining or leaving the network, IP addresses being allocated, MAC addresses associated with IP addresses, or DNS entries being updated. This visibility ensures that the NSoT is always aligned with actual network activity.

6. Conflict Prevention and Issue Resolution

One of the critical roles of a DDI solution is to prevent network conflicts (such as IP address conflicts) and provide tools for quickly resolving issues:

• IP Address Conflicts: If two devices are assigned the same IP address (either statically or through DHCP), the DDI system detects and resolves the conflict by either re-assigning IPs or alerting network administrators and proposing possible remediations. This ensures that the NSoT remains accurate and does not contain conflicting data.
• DNS Resolution Issues: If a device is not responding to its DNS queries or if there is a DNS misconfiguration (e.g. an invalid or missing DNS record), the DDI solution provides insights into DNS resolution issues, allowing administrators to quickly troubleshoot and update the NSoT.
• MAC Address Inconcistencies: If built-in asset discovery tools report a device’s MAC address that differs from the one stored in IPAM, the DDI solution lists the inconsistency and, if approved by the administrator, suggests ways to remediate and change the MAC address in IPAM.

7. Scalability and Flexibility

A DDI solution can scale to accommodate distributed, complex networks by managing large address spaces and providing flexibility in terms of subnets, VLANs, and IP ranges. As the network grows, the NSoT adapts to reflect the new network architecture, ensuring that all changes – whether they’re related to IP addressing, DNS records, or DHCP configurations – are seamlessly integrated into the source of truth.

Example Workflow of DDI in NSoT:

1. Device joins the network: A device requests an IP address from the DHCP server.
2. IP address assignment: DHCP assigns an IP address and updates the IPAM system, which logs the new allocation in the NSoT.
3. DNS update: The DNS system automatically creates or updates a DNS record for the device to associate its hostname with the newly assigned IP address, ensuring the device can be found by name.
4. Track and log: IPAM tracks the usage of the IP address, logging the lease information and making it available for reporting and troubleshooting.
5. Network audit: Administrators can run reports from the DDI system, checking for conflicts, historical changes, or trends in IP address usage, all of which are part of the NSoT.

To summarize, a DDI solution creates a Network Source of Truth by acting as the central repository for the core network data – DNS records, IP addresses, and DHCP leases. It ensures accuracy, consistency, and real-time updates across the network by tightly integrating these components, tracking and reconciling changes, and providing visibility. This results in an open, reliable, up-to-date view of the network that is essential for scaling robust end-to-end automation of network management tasks, efficient network operations, and troubleshooting. By doing this, it helps networking teams simplify and maintain compliance.

Conclusion

A Network Source of Truth is essential for ensuring reliable network operations, improving network visibility, supporting automation, and maintaining consistency and compliance across all network management activities.