Data Center Trends: Automation, AI-ready Infrastructure and ACI

Data Center Trends – Automation, AI-ready Infrastructure and ACI

Digital transformation and generative AI have triggered a revolution in data centers. Below I summarize the most important trends from the last 12‑18 months.

AI‑ready infrastructure and new switches

– In February 2025 Cisco unveiled new 9300 switches with built‑in Data Processing Units (DPUs). These provide 800 Gbps throughput and 128 GB memory and can run security services such as Layer†4 stateful firewalling, NAT, IPSec, telemetry and DDoS protection directly on the switch. This architecture reduces latency and simplifies network design because security functions are moved into the network infrastructure.

– Solutions for intensive AI workloads are becoming more flexible. Drut, a software company, released in 2024 the DX3.0 system, which creates virtual "vPODs" made of CPU, GPU and memory slices from multiple servers. This allows dynamic allocation of expensive GPU resources and increases utilization — even 6 of 8 GPU cards in a single server can be assigned to other tasks. It’s an example of how data centers are becoming more modular and AI‑ready.

State of network automation and orchestration

 

 

 

 

 

 

– The NetBox Labs report (based on EMA research) from April 2024 shows that only 27 % of network teams report full success in managing complex infrastructure. 80 % of successful automation projects were fully funded, whereas only 57 % of partially successful projects enjoyed full funding. At the same time, 76 % of organizations expect their network automation budgets to grow within the next two years. This underscores growing interest in automation. 

 

 

 

 

 

 

 

 

 

– Results from the "State of Network Automation Survey 2024" (Packet Pushers) show that among 106 respondents, 58 have automated up to 50 % of their networks while 48 have automated more than 50 %. The most commonly automated tasks include backups, device deployment, firmware upgrades, service provisioning and firewall rules. However, 81 % of respondents rely on their own scripts rather than commercial tools.

Orchestration with ACI

 

– Cisco’s Application Centric Infrastructure (ACI) combines network automation, policy orchestration and monitoring in a single ecosystem. According to Techniche data from 2023, ACI already has more than 6 000 production customers. Cisco has numerous case studies across industries and continues to expand ACI with multi‑cloud support – for example, Amazon Web Services and Microsoft Azure.

– Growing interest in automation suggests that more enterprises are considering migration to ACI and similar platforms. Although there are no official statistics, the NetBox Labs report indicates that 76 % of organizations want to increase their automation budgets and that fully funded projects dramatically increase the chance of success. These figures suggest that many companies plan to adopt centralized solutions like ACI.

Summary

New technologies — such as switches with DPUs and virtual compute pools — are designed to handle rising AI workloads. At the same time, the challenges of managing networks are pushing companies toward automation and platforms like ACI. More than six thousand organizations have already implemented ACI, and rising automation budgets indicate that this number is likely to increase. In the coming years, success in automation will depend on well‑funded projects and the adoption of proven orchestration platforms.

Weekly Networking News: Cisco, Juniper & Nokia (Aug 3, 2025)

This week’s networking news round‑up explores how the industry’s biggest vendors are pushing the boundaries of AI‑ready networks, data centre fabrics and service provider solutions.

Cisco – AI‑ready networks and data centres

At Cisco Live 2025, Cisco’s leadership highlighted a bold pivot: the company is positioning itself as an AI‑driven firm with networking at its core. The focus is on building AI‑ready networks that can support the massive data flows generated by training and inference workloads. Cisco announced new high‑capacity switches based on its Silicon One chips, an AI Canvas to accelerate AI development, and integrated security and observability tools such as Hypershield. This shift from simply delivering network hardware to providing a unified platform underscores how important data centre networking has become in the age of agentic AI.

 

 

Juniper – AI‑nati vedata centre and routing

Juniper’s AI‑Native Networking Platform, now part of HPE, integrates Mist AI, the Marvis virtual assistant and Apstra automation to simplify operations across campus, data centre and WAN. Juniper says its AI data centre solution provides a quick way to deploy high‑performance AI training and inference networks while remaining flexible and easy to manage. On the WAN side, the company’s AI‑native routing family delivers robust 400 GbE and 800 GbE capabilities for high performance, reliability and sustainability. This combination of automation and high‑speed hardware earned Juniper recognition as a leader in the 2025 Magic Quadrant for enterprise wired and wireless LAN infrastructure.

Nokia – Visionary in data centre switching

Nokia was named a Visionary in the 2025 Gartner Magic Quadrant for data centre switching. The company’s portfolio includes the 7220 and 7250 IXR platforms, SR Linux operating system and Event‑Driven Automation framework, with options to run community SONiC software. These switches support 400 GbE and 800 GbE speeds and emphasise automation and reliability, reflecting Nokia’s vision for AI‑native data centres and service provider networks. The recognition underscores both the completeness of Nokia’s vision and its ability to execute in the data centre market.

Summary

Across the board, networking vendors are rapidly adapting to AI’s demands. Cisco is refocusing its strategy around AI‑ready data centre networks; Juniper, under HPE, is promoting AI‑native platforms that combine high‑speed hardware with automation; and Nokia is expanding its vision with next‑generation switching fabrics. We’ll continue monitoring these developments every Monday, Wednesday and Friday to keep you informed of the latest trends.

OSPF Neighbor States: Step‑by‑Step

Understanding OSPF Neighbor States and Adjacency Formation

Open Shortest Path First (OSPF) is a link-state IGP (Interior Gateway Protocol) designed for efficient, scalable, and fast convergence in enterprise and service provider networks. Before routers can exchange routing information, they must become neighbors and go through a well-defined finite-state machine to synchronize their Link-State Databases (LSDBs). A deep understanding of each OSPF neighbor state and the LSA exchange process is critical for troubleshooting and optimizing OSPF behavior in complex topologies.

 

OSPF Neighbor State

OSPF adjacency formation progresses through a series of states, each representing a specific phase in the neighbor relationship:

1. Down 

• This is the initial state.

• No Hello packets have been received from the neighbor.

• The router may still be sending Hello packets.

2. Attempt (only for NBMA networks)

• The router actively sends unicast Hello packets to a configured neighbor.

• No Hello has been received yet from that neighbor.

3. Init 

• A Hello packet has been received from the neighbor.

• However, the router's own Router ID is not yet seen in the neighbor's Hello packet.

• Communication is unidirectional.

4. 2-Way 

• Bi-directional communication is established.

• The router sees its own Router ID in the neighbor's Hello packet.

• DR and BDR election occurs on broadcast and NBMA networks.

• On point-to-point networks, routers may move directly to the next state.

5. ExStart 

• Routers negotiate master-slave roles.

• They select initial sequence numbers for Database Description (DBD) packets.

• This phase prevents simultaneous DBD packet exchange and ensures order.

6. Exchange 

• Routers exchange DBD packets summarizing their LSAs.

• Each LSA summary includes type, ID, advertising router, and sequence number.

• Routers build a list of LSAs they need from their neighbor.

7. Loading 

• The router sends Link State Request (LSR) packets for missing or outdated LSAs.

• The neighbor responds with Link State Update (LSU) packets containing the full LSA.

• Routers install received LSAs in the LSDB.

8. Full 

• LSDBs are fully synchronized.

• The routers are fully adjacent.

• On broadcast and NBMA networks, only DR and BDR form Full adjacencies with other routers

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AI‑Native Networking: How Juniper’s HPE Acquisition and Cisco Live 2025 Signal a New Era for Data Centers

 The networking industry is at an inflection point, where artificial intelligence workloads and the demands of modern data centers are forcing vendors to rethink their architectures. In July 2025, Hewlett Packard Enterprise completed its US$14 billion acquisition of Juniper Networks, creating a combined HPE Networking business that doubles HPE’s networking revenue and positions it as a direct competitor to Cisco. A month earlier, Cisco used its Cisco Live 2025 conference to unveil an AI‑first vision for networking.

## HPE–Juniper: building an AI‑native competitor to Cisco

HPE’s acquisition brings Juniper’s data‑center and service‑provider expertise — think EVPN‑VXLAN fabrics, high‑performance routing and Mist AI — under the same roof as HPE’s Aruba campus networking and GreenLake cloud platform. Juniper’s former CEO, Rami Rahim, now leads the combined organization. The integration aims to give customers a unified network architecture spanning enterprise, data center and service‑provider segments, with consistent management across on‑premises and cloud deployments. For network architects, this promises simplified hybrid‑cloud implementations and new competition to Cisco’s dominant market position.

## Cisco Live 2025: agentic AI and AI‑ready networks

At Cisco Live 2025, Cisco’s president and chief product officer Jeetu Patel announced a cascade of AI‑driven solutions designed to modernize infrastructure and revolutionize IT operations. Key highlights include:

• AgenticOps and the Deep Network Model – a domain‑specific large language model trained on decades of Cisco expertise that diagnoses network issues and troubleshoots automatically.

• AI Canvas and Intelligent Workspace – a generative AI interface for NetOps, SecOps and DevOps teams, scheduled for general availability in October 2025.

• Secure and scalable AI‑ready networks – a unified management platform for Catalyst, Meraki and industrial devices; ThousandEyes assurance integrated with Splunk monitoring; and a quantum‑resistant security model.

• Hardware refresh – routers offering up to three times the throughput of prior models and Catalyst switches delivering up to 1.6 terabits per second of stacked bandwidth.

Cisco is also partnering with OpenAI to develop compute clusters tailored for large language models. The message is clear: AI will be deeply embedded in network operations, and networks must be designed to support AI workloads.

## Why AI needs data‑center networking innovation

Training large language models requires moving terabytes of data between hundreds of GPUs, creating east–west traffic patterns that overwhelm legacy data‑center networks. Modern fabrics use technologies such as EVPN‑VXLAN, segment routing and RDMA over Converged Ethernet to deliver high bandwidth and low latency. Both HPE‑Juniper and Cisco are investing heavily to ensure their platforms meet these requirements. For network engineers, this convergence of AI and networking marks a new chapter: understanding protocols like EVPN, segment routing and BGP EVPN will be essential for designing AI‑ready data centers.

## Conclusion

The convergence of networking and AI is transforming how data centers are built and operated. HPE’s integration of Juniper brings Mist AI and EVPN fabrics into a larger portfolio, while Cisco’s agentic AI and AI‑ready architecture offer a unified platform and refreshed hardware. Staying ahead means keeping pace with these developments and mastering the underlying technologies. Stay tuned for upcoming posts where we’ll dive deeper into protocols like OSPF, IS‑IS and segment routing — and explore how they support the AI‑native networks of tomorrow.

 Lately I've been spending a lot of time on projects related to migrating traditional MPLS (based on LDP) to a new solution based on MPLS Segment Routing. Migrations can be challenging and very interesting, so I’ll try to illustrate, using the example of several clients – of course, the data will be anonymized – what the migration process looks like and what its main advantages are. I'm returning to running this blog because it gives me the motivation for further activities and learning. I hope there will be readers for what I share here and that it will be useful to someone.

Reflecting on the value of CCIE and how it opened opportunities

 

Just wanted to come back to write this blog. I have been a CCIE for a few years now and wanted to share with you how many doors and opportunities it has opened for me. I am currently trying to motivate myself to study for the CCDE and focus on the world of AI, which is increasingly fascinating to me.

First, I asked AI for its current opinion on CCIE and CCDE. It seems that it's still worth going on this journey and focusing on learning.

That's why I will be posting various summaries from the world of Networking and AI here.

 

The CCIE (Cisco Certified Internetwork Expert) and CCDE (Cisco Certified Design Expert) certifications are among the most prestigious credentials in the IT industry, offering a wide range of technical and career opportunities. Here’s a deeper look at what they bring to the table:

CCIE (Cisco Certified Internetwork Expert):

1. Advanced Technical Expertise:

   • The CCIE certification validates your ability to design, implement, and troubleshoot complex network infrastructures.

   • It covers advanced topics such as routing and switching (CCIE Enterprise), data center technologies, security, service provider, and wireless networks.

   • You’ll gain hands-on experience with cutting-edge Cisco technologies, including SD-WAN, automation, and network programmability.

2. Career Growth:

   • Opens doors to high-level roles such as Senior Network Engineer, Network Architect, or Technical Consultant.

   • Employers value CCIE-certified professionals for their ability to solve complex network challenges and optimize performance.

3. Global Recognition:

   • CCIE is globally recognized as a gold standard in networking expertise, giving you credibility and respect in the industry.

4. Salary Potential:

   • CCIE-certified professionals often command higher salaries due to their specialized skills and ability to handle mission-critical networks.

5. Personal Satisfaction:

   • Achieving CCIE is a challenging but rewarding journey that brings a deep sense of accomplishment and confidence in your technical abilities.

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CCDE (Cisco Certified Design Expert):

1. Network Design Mastery:

   • The CCDE certification focuses on advanced network design principles, enabling you to create scalable, secure, and efficient network architectures.

   • It emphasizes strategic thinking, including business requirements, technical constraints, and risk management.

   • You’ll learn to design solutions for large-scale networks, integrating technologies like MPLS, QoS, and cloud connectivity.

2. Strategic Roles:

   • Prepares you for roles such as Network Design Architect, Solutions Architect, or Technical Lead.

   • You’ll be responsible for designing networks that align with business goals and future-proof organizations.

3. Global Impact:

   • CCDE is recognized worldwide as a mark of excellence in network design, making you a sought-after expert for global projects.

4. Salary Potential:

   • CCDE-certified professionals often earn top-tier salaries due to their ability to design innovative and cost-effective solutions.

5. Personal Satisfaction:

   • Earning the CCDE certification is a testament to your ability to think strategically and solve complex design challenges, bringing immense professional pride.

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Why Pursue CCIE or CCDE?

• Technical Mastery: Both certifications push you to the forefront of networking technology, giving you the skills to work with the latest tools and methodologies.

• Career Advancement: They open doors to leadership roles, consulting opportunities, and high-impact projects.

• Global Opportunities: With these certifications, you can work anywhere in the world, as they are recognized and respected across industries.

• Personal Growth: The rigorous preparation process is intellectually stimulating and builds resilience, problem-solving skills, and confidence.

• Community and Recognition: Joining the elite group of CCIE and CCDE holders connects you with a global network of experts and thought leaders.

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Conclusion:

Pursuing CCIE or CCDE is not just about earning a certification—it’s about transforming your career and becoming a leader in the networking field. The journey is demanding, but the rewards are immense: technical mastery, career growth, global recognition, and personal satisfaction. If you’re passionate about networking and ready to take your skills to the next level, CCIE and CCDE are the ultimate goals to strive for. They don’t just validate your expertise—they redefine what you’re capable of achieving.

Why Migrate from MPLS to Segment Routing?

 

Why Migrate from MPLS to Segment Routing? A Comprehensive Guide

In today’s rapidly evolving networking landscape, enterprises face the constant challenge of optimizing their network infrastructure to meet growing demands for performance, scalability, and flexibility. One of the key trends in recent years is the migration from traditional MPLS (Multiprotocol Label Switching) to modern technologies like Segment Routing (SR). In this article, we will explore why migrating from MPLS to Segment Routing is a strategic move, the benefits it offers, and a detailed overview of the migration process from LDP (Label Distribution Protocol) to SR.

 

Why Migrate from MPLS to Segment Routing?

1. Simplified Network Architecture

MPLS, while effective, requires complex configuration and management, especially in large-scale networks. Segment Routing simplifies network architecture by eliminating the need for additional protocols like LDP or RSVP-TE (Resource Reservation Protocol - Traffic Engineering). In SR, path information is encoded directly in packet headers, reducing the number of protocols and management mechanisms.

2. Improved Scalability

Segment Routing offers better scalability compared to MPLS. In traditional MPLS networks, each router must maintain the state of every label for every path, which can lead to significant memory and CPU overhead in large networks. SR stores path information more efficiently, enabling easier network scaling without requiring additional hardware resources.

3. Enhanced Traffic Control and Flexibility

SR provides greater flexibility in traffic engineering. By allowing administrators to define application-specific paths (segments), SR enables precise control over how traffic flows through the network. This is particularly useful for applications requiring high availability, such as cloud services or business-critical applications.

4. Seamless Integration with SDN (Software-Defined Networking)

Segment Routing is inherently compatible with SDN architectures, enabling greater automation and optimization. By integrating with SDN controllers, SR allows for dynamic traffic management, automatic fault detection, and fast rerouting, resulting in higher network availability and reliability.

5. Cost Reduction

Migrating to Segment Routing can lead to significant cost savings. The simplified architecture and reduced management requirements mean IT teams can operate more efficiently, and the costs associated with network maintenance can be significantly reduced. Additionally, SR can operate on existing MPLS infrastructure, allowing for a gradual migration without the need for immediate hardware upgrades.

6. Support for Modern Applications

In the era of digital transformation, enterprises are increasingly deploying modern applications such as IoT (Internet of Things), AI (Artificial Intelligence), and cloud-based services. Segment Routing is better suited to meet the demands of these applications, offering lower latency, higher throughput, and improved traffic control.

7. Easier Inter-Domain Traffic Management

For wide-area networks (WANs) or service provider networks, SR simplifies inter-domain traffic management. By enabling end-to-end path definition, SR allows for more efficient traffic management across different network domains, which is particularly important for large enterprises and telecom operators.

8. Future-Proofing with IPv6 Support

Segment Routing is designed with the future in mind, including full support for IPv6. As more organizations transition to IPv6, SR ensures a smooth migration and integration with new networking standards.

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The Migration Process: From LDP to Segment Routing

Migrating from LDP-based MPLS to Segment Routing requires careful planning and execution. Below is a step-by-step guide to ensure a smooth transition:

1. Assess Your Current Network

• Inventory Your Network: Document all devices, links, and configurations in your MPLS network.

• Identify Dependencies: Determine which applications and services rely on LDP and MPLS.

• Evaluate Hardware and Software Compatibility: Ensure your network devices support Segment Routing. Most modern routers and switches support SR, but older hardware may require upgrades.

2. Design the Segment Routing Architecture

• Define Segment Routing Domains: Decide where SR will be implemented (e.g., core, edge, or entire network).

• Plan Segment Identifiers (SIDs): Allocate Node SIDs, Adjacency SIDs, and any other required SIDs.

• Design Traffic Engineering Policies: Define how traffic will be steered using SR policies, especially for critical applications.

3. Configure Segment Routing

• Enable SR on Devices: Configure SR on routers and switches, ensuring compatibility with existing MPLS infrastructure.

• Configure IGP (Interior Gateway Protocol): Use protocols like OSPF or IS-IS to distribute SIDs and SR information.

• Implement SR Policies: Define and deploy SR policies for traffic engineering and path optimization.

4. Test the SR Configuration

• Conduct Lab Testing: Test the SR configuration in a lab environment to validate functionality and performance.

• Simulate Failures: Test fault tolerance and rerouting capabilities to ensure network resilience.

• Verify Interoperability: Ensure SR works seamlessly with existing MPLS and LDP configurations.

5. Gradually Migrate Traffic

• Start with Non-Critical Traffic: Begin by migrating less critical traffic to SR to minimize risk.

• Monitor Performance: Use network monitoring tools to track performance and identify any issues.

• Migrate Critical Traffic: Once the SR network is stable, migrate critical applications and services.

6. Decommission LDP

• Disable LDP on Devices: Once all traffic has been migrated to SR, disable LDP on routers and switches.

• Remove LDP Configurations: Clean up any remaining LDP configurations to simplify the network.

7. Optimize and Maintain

• Fine-Tune SR Policies: Continuously optimize SR policies based on network performance and traffic patterns.

• Monitor and Troubleshoot: Use monitoring tools to proactively identify and resolve issues.

• Train Your Team: Ensure your network team is trained on Segment Routing concepts and management.

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Key Considerations During Migration

• Phased Approach: A gradual migration reduces risk and allows for thorough testing at each stage.

• Backup and Rollback Plans: Always have a rollback plan in case of unexpected issues during migration.

• Vendor Support: Work closely with your hardware and software vendors to ensure compatibility and resolve any issues.

• Documentation: Keep detailed documentation of the migration process, configurations, and changes for future reference.

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Conclusion

Migrating from MPLS to Segment Routing is a strategic decision that can bring significant benefits to your organization, including simplified architecture, improved scalability, enhanced traffic control, and cost savings. The migration process, particularly from LDP to SR, requires careful planning, testing, and execution, but the long-term advantages far outweigh the initial effort.

By adopting Segment Routing, your organization can build a more efficient, flexible, and future-proof network capable of meeting the demands of modern applications and digital transformation. If you’re considering this migration, consult with networking experts to develop a tailored strategy that ensures a smooth and successful transition.

 

Segment Routing vs. Traditional MPLS: A Modern Approach to Traffic Engineering

 

1. Introduction

Modern networks strive for greater efficiency, simpler management, and enhanced flexibility. Segment Routing (SR) has emerged as a powerful alternative to traditional MPLS (Multiprotocol Label Switching), eliminating many of its limitations, such as reliance on Label Distribution Protocol (LDP) and RSVP-TE for signaling. This article compares SR-MPLS with classical MPLS and explores its key advantages, including a step-by-step migration process illustrated with network diagrams.

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2. Traditional MPLS and Its Limitations

MPLS uses labels for efficient packet forwarding, relying on LDP for label distribution or RSVP-TE for traffic engineering. While MPLS has served networks well, it faces challenges in scalability and complexity.

Limitations of MPLS:

• LDP dependency: A separate protocol for label distribution, increasing overhead.

• No native ECMP support: RSVP-TE lacks equal-cost multipath (ECMP) forwarding.

• Complex control plane: Each router must maintain LDP sessions, increasing memory and processing requirements.

• Traffic engineering challenges: Requires additional mechanisms such as RSVP-TE or centralized SDN controllers.

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3. Segment Routing: A Modern Alternative

Segment Routing (SR-MPLS) simplifies network design by encoding the forwarding path within the packet itself using Segment Identifiers (SIDs). Instead of relying on LDP, SR uses existing IGP (OSPF/IS-IS) extensions to distribute labels.

Advantages of SR:

• No need for LDP: Simplifies the control plane.

• Uses IGP for label distribution: Eliminates additional protocols.

• Stateless core: Reduces memory and processing overhead on routers.

• Better traffic engineering: Native support for SR-TE (Segment Routing Traffic Engineering).

• Built-in ECMP: Efficient utilization of available paths.

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4. Migration from MPLS-LDP to Segment Routing

Migration to SR is typically done in phases to minimize service disruption. The following sections illustrate this transition with network diagrams.

4.1 Initial State: MPLS Network with LDP

In this stage, the network is fully MPLS-based, with LDP used for label distribution.

(Image: Traditional MPLS Network with LDP)

4.2 Hybrid State: Coexistence of LDP and SR

During migration, both LDP and SR run in parallel, allowing gradual migration of routers to SR.

(Image: Hybrid Network with MPLS-LDP and Segment Routing)

4.3 Fully Migrated State: Pure SR-MPLS Network

Once all routers support SR, LDP is removed, simplifying the network architecture.

(Image: Fully Migrated Segment Routing Network)

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5. Configuration Examples

5.1 MPLS-LDP Configuration (Traditional Approach)

router isis 1
 net 49.0001.0000.0000.0001.00
 is-type level-2
 metric-style wide

mpls ip
mpls label protocol ldp
interface GigabitEthernet0/0/0
 mpls ip
 mpls ldp

router ldp
 mpls ldp router-id Loopback0 force

5.2 Segment Routing Configuration

router isis 1
 net 49.0001.0000.0000.0001.00
 is-type level-2
 metric-style wide
 segment-routing mpls

interface GigabitEthernet0/0/0
 ip router isis 1

segment-routing
 mpls
  set srgb 16000 23999
  node-sid 16001

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6. Conclusion

Segment Routing provides a more scalable, flexible, and efficient alternative to traditional MPLS-LDP. By eliminating LDP and RSVP-TE, SR-MPLS simplifies operations, reduces control plane overhead, and enables advanced traffic engineering. Migrating to SR can be done in phases to ensure smooth adoption without disrupting services.

Segment Routing: Why It Matters and Why It's Worth the Migration

 

Segment Routing (SR) is reshaping the way modern IP/MPLS networks are designed, operated, and optimized. As service providers and enterprises face growing demands for scalability, automation, and fast convergence, traditional MPLS control-plane protocols like LDP and RSVP-TE are showing their limitations. Segment Routing offers a cleaner, more scalable, and SDN-ready alternative. Here's why SR is gaining traction—and why it's worth considering for your network.

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1. The Problem with Traditional MPLS

Traditional MPLS networks rely heavily on LDP or RSVP-TE for label distribution and traffic engineering. While these protocols are proven and widely deployed, they come with significant overhead:

• Complex configuration and maintenance

• Per-flow or per-tunnel state in the network core

• Multiple signaling protocols to manage

• Limited ECMP (Equal-Cost Multi-Path) awareness

• Non-trivial Fast Reroute (FRR) mechanisms

This operational complexity becomes a major bottleneck in large or highly dynamic networks.

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2. The Segment Routing Advantage

Segment Routing radically simplifies the control plane by removing the need for LDP or RSVP. Instead, SR encodes the path into the packet itself, using a list of instructions known as segments.

✅ Key Benefits over LDP/RSVP-TE:

Feature	MPLS + LDP/RSVP-TE	Segment Routing
Protocol overhead	High (multiple protocols)	Low (IGP extensions only)
Core state	Per-flow or per-tunnel	Stateless core
Fast reroute (FRR)	RSVP-TE or IP FRR	Built-in TI-LFA
ECMP support	Limited	Full support
SDN compatibility	Limited or complex	Native
Migration path	Complex	Gradual + interop with LDP

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3. Why Migrate to SR Now?

🔁 Simplified Operations

• No more RSVP or LDP troubleshooting

• Only OSPF or IS-IS with SR extensions needed

⚙️ Works on Existing Infrastructure

• Supports both SR-MPLS and SRv6

• Requires no hardware replacement in most modern routers

🔄 Coexistence and Smooth Migration

• SR can run in parallel with LDP

• Interoperability ensures step-by-step deployment

🧠 SDN Ready

• Seamless integration with centralized controllers (e.g., PCE)

• Enables intent-based networking and automation

💸 Reduced Costs

• Fewer protocols, less state = lower resource usage and OPEX

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4. Powerful Features That Make SR Stand Out

🎯 Traffic Engineering (SR-TE)

• Define explicit paths using segment lists

• Combine prefix-SIDs (for IGP-based routing) and adjacency-SIDs (for specific links)

• Use either distributed (IGP) or centralized (PCE) path control

⚡ Fast Reroute with TI-LFA

• Topology-Independent Loop-Free Alternate (TI-LFA)

• <50ms recovery from link/node/SRLG failures

• No RSVP state, no pre-signaled tunnels

🧩 Flex-Algo

• Define custom routing topologies inside a single IGP domain

• Example: low-latency routing using Flex-Algo 128

• Enables SLA-driven path selection

🔁 Loop-Free, Deterministic Paths

• Ingress-defined segment lists ensure predictable forwarding

• Avoids routing loops and black holes

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5. Final Thoughts: SR as the Foundation for Modern Networks

Segment Routing is not just another routing tweak. It is a fundamental evolution of how we think about transport in IP/MPLS networks. By removing legacy complexity and enabling granular, programmable control over traffic paths, SR sets the stage for highly automated, resilient, and scalable infrastructures.

Whether you’re preparing for 5G transport, large-scale metro deployments, or just simplifying your core, SR offers the tools to future-proof your network.

👉 Now is the time to consider Segment Routing—not just for what it replaces, but for what it unlocks.

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OSPF Packet Types

 

OSPF Packet Types Explained: The 5 Key Messages in OSPF

Open Shortest Path First (OSPF) uses five distinct packet types to perform its functions as a link-state routing protocol. These packet types allow OSPF routers to discover neighbors, exchange routing information, ensure synchronization of link-state databases (LSDBs), and maintain reliability in the network. Each packet type plays a crucial role during different stages of neighbor formation and database synchronization.

In this article, we'll break down each of these OSPF packet types, explaining their purpose and behavior within the OSPF finite state machine.

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1. Hello Packet

Purpose: Discover and maintain neighbor relationships.

• Sent periodically on all OSPF-enabled interfaces.

• Used to discover new neighbors and ensure existing neighbors are still active.

• Contains key parameters such as Router ID, Hello/Dead intervals, network mask, options, and designated router info.

• Neighbor relationships only form between routers with matching parameters.

Used in states: Down, Init, 2-Way

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2. Database Description (DBD or DDP) Packet

Purpose: Summarize LSDB contents to neighbor routers.

• Exchanged during the Exchange state.

• Routers describe their link-state database content using LSA headers.

• Helps routers identify which LSAs are missing or outdated.

• Includes sequence numbers and master/slave negotiation in ExStart.

Used in states: ExStart, Exchange

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3. Link-State Request (LSR) Packet

Purpose: Request missing or outdated LSAs from a neighbor.

• Sent by a router when it detects a missing or stale LSA.

• Generated after comparing LSA summaries received in DBD packets.

• Requests are specific and precise (type, ID, advertising router).

Used in state: Loading

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4. Link-State Update (LSU) Packet

Purpose: Transmit full LSA contents in response to LSRs.

• Contains one or more complete LSAs.

• Used to update a neighbor’s database with detailed link-state information.

• Sent in direct response to LSRs, but can also be used to flood LSAs.

Used in state: Loading

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5. Link-State Acknowledgment (LSAck) Packet

Purpose: Ensure reliable LSA flooding and delivery.

• Acknowledges receipt of LSUs.

• Prevents retransmission and confirms LSA reception.

• Can be sent as direct, delayed, or summary acknowledgments.

Used in state: Loading

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Summary Table

Type	Packet Name	Functional Overview
1	Hello	Discover & maintain neighbor relationships
2	Database Description (DBD)	Summarize LSDB contents
3	Link-State Request (LSR)	Request missing LSAs from neighbor
4	Link-State Update (LSU)	Send full LSAs to update neighbor's database
5	Link-State Acknowledgment	Confirm reliable LSA delivery and flooding