Saturday, May 16, 2026

CCDE Enterprise Case Study Part 1: Jacobs MPLS WAN, DCI, QoS, Data Center & Cloud Architecture Analysis

CCDE Enterprise Architecture Case Study Part 1 – Jacobs WAN, MPLS, DCI and Data Center Analysis

CCDE Enterprise Architecture Case Study Part 1 – Jacobs WAN, MPLS, DCI and Data Center Analysis

Enterprise architecture is no longer limited to routing protocols and switch configurations. Modern enterprise architects must understand:

  • Business transformation
  • Mergers and acquisitions
  • Cloud migration
  • WAN scalability
  • Operational simplicity
  • Security segmentation
  • Application behavior
  • Customer experience
  • Supply chain dependencies

This complete CCDE-level case study analyzes the enterprise architecture of Jacobs, a large UK-based building merchant with multiple WAN providers, multiple data centers, separate operational entities, and evolving business requirements.

🎯 What You Will Learn

  • Enterprise WAN design analysis
  • MPLS provider architecture
  • DCI operational challenges
  • Cloud migration problems
  • Office 365 SaaS optimization
  • QoS design methodology
  • EIGRP and OSPF integration
  • VoIP resiliency architecture
  • MPLS VPN design analysis
  • Security policy implications
  • Business-driven architecture decisions
  • Capacity planning methodologies

Table of Contents

1. Business Background Analysis

Jacobs began as a single store in Chelsea, London in 1982.

The founder identified inefficiencies in the building supply chain and optimized material availability for local contractors.

This is important from an architectural perspective because:

  • The business was built around operational efficiency
  • Customer experience remains critical
  • Supply chain responsiveness directly impacts profitability

As the organization expanded nationally, it acquired:

  • 102 independent building merchants
  • Toolmate competitor brand
  • Multiple disconnected IT systems

Enterprise Complexity Formula

$$ Complexity = Stores + Applications + WANs + Vendors + Acquisitions $$

As acquisitions increase:

$$ Operational\\ Complexity \uparrow $$

2. Merger and Acquisition Challenges

One of the largest enterprise networking challenges is integration after acquisition.

Jacobs acquired Toolmate but allowed:

  • Independent operations
  • Separate WAN architecture
  • Separate routing domains
  • Separate DC operations

Only limited integration occurred:

  • VoIP integration
  • HR systems
  • Intranet access

💡 Critical CCDE Observation

This is extremely realistic.

Most enterprise acquisitions do NOT immediately integrate:

  • Routing protocols
  • Applications
  • Security models
  • WAN providers

Architects must account for:

  • Political boundaries
  • Operational boundaries
  • Change management delays
  • Business continuity requirements

3. Current Enterprise Network Architecture

The network currently consists of:

Entity WAN Provider Routing Design
Jacobs Bluesky + Taco OSPF + BGP Dual MPLS
Toolmate Lotnet EIGRP + BGP Dual MPLS
Independent Stores Annet BGP Static Single MPLS

Immediately we can identify:

  • Operational inconsistency
  • Routing complexity
  • Different QoS models
  • Different resiliency models
  • Different security models

Architecture Fragmentation Formula

$$ Fragmentation \propto Providers + Routing\\ Protocols + Security\\ Models $$

4. Jacobs Store WAN Design

Jacobs stores use:

  • Dual MPLS providers
  • VRRP default gateways
  • Static routing
  • BGP redistribution
  • VoIP prioritization

Why This Design Exists

The design prioritizes:

  • Operational simplicity
  • Resiliency
  • Voice quality

But There Are Problems

  • Taco circuits remain underutilized
  • Expensive standby bandwidth
  • Inefficient traffic engineering
  • Poor cloud optimization

Bandwidth Waste Formula

$$ Unused\\ Capacity = Provisioned - Utilized $$

From utilization graphs:

$$ Taco\\ Utilization \approx 0.1Gbps $$

While:

$$ Provisioned = 10Gbps $$

This means:

$$ 99\%\\ of\\ capacity\\ is\\ idle $$

5. Toolmate WAN Design

Toolmate uses:

  • Single MPLS provider
  • Dual CE routers
  • ECMP routing
  • EIGRP internally
  • BGP externally

Advantages

  • Better link utilization
  • Active/active forwarding
  • Simpler failover

Disadvantages

  • Single provider dependency
  • No transport diversity
  • Operational inconsistency with Jacobs

ECMP Utilization Formula

$$ Traffic_{Total} = Link_1 + Link_2 $$

This allows:

$$ 50\% + 50\% = 100\% $$

resource utilization.

6. Independent Store Architecture

Independent stores are dramatically different.

Characteristics include:

  • Single WAN circuit
  • No redundancy
  • Traditional telephony
  • Limited shared services
  • No Internet from MPLS

Why?

Because these stores operate semi-independently.

The business accepted:

  • Reduced resiliency
  • Limited integration
  • Lower operational investment

💡 Important Architecture Lesson

Not every branch requires the same architecture.

Architects must design according to:

  • Business criticality
  • Revenue impact
  • Operational dependency
  • Cost sensitivity

7. MPLS Provider Design Analysis

Jacobs MPLS

  • Bluesky = Primary
  • Taco = Backup
  • VRRP failover
  • QoS for VoIP

Toolmate MPLS

  • Lotnet only
  • ECMP forwarding
  • Dual active WAN

Independent Stores MPLS

  • Hub-and-spoke only
  • No Internet routing
  • PBR enforced

MPLS Availability Formula

$$ Availability = 1 - Failure\\ Probability $$

Dual-provider WAN increases:

$$ Availability \uparrow $$

But also increases:

$$ Operational\\ Complexity \uparrow $$

8. BGP Design Analysis

Jacobs uses:

  • BGP AS 64555 in stores
  • AS override
  • iBGP between providers

Code Example

router bgp 64555
 neighbor 10.1.1.1 remote-as 65000

router bgp 64555
 neighbor 10.1.1.1 remote-as 65000
 neighbor 10.1.1.1 next-hop-self
 redistribute static
Why AS Override Is Required

All stores use the same AS:

$$ 64555 $$

Without AS override:

  • BGP loop prevention blocks advertisements
  • Remote stores cannot learn routes

BGP Path Selection Simplification

$$ Best\\ Path = Highest\\ Weight + Highest\\ Local\\ Preference + Shortest\\ AS\\ Path $$

9. QoS and VoIP Analysis

VoIP traffic is business critical.

Current WAN QoS prioritizes voice traffic.

But Several Problems Exist

  • Cloud traffic increases congestion
  • Office 365 is latency sensitive
  • WAN links operate inefficiently
  • Voice and SaaS compete for bandwidth

Voice Quality Formula

$$ MOS \propto \frac{1}{Latency + Jitter + Packet\\ Loss} $$

Code Example

policy-map WAN-QOS
 class VOICE
  priority percent 30

class-map match-any VOICE
 match dscp ef

policy-map WAN-QOS

 class VOICE
  priority percent 30

 class BUSINESS-CRITICAL
  bandwidth percent 40

 class class-default
  fair-queue
QoS Design Explanation

Voice traffic requires:

  • Low latency
  • Low jitter
  • Minimal packet loss

Priority queuing ensures voice traffic is serviced first.

10. DCI Design and Challenges

The DCI is one of the most critical architectural problems.

Current DCI:

  • Dual 1Gbps Layer 3 links
  • OSPF peering
  • Firewall traversal required
  • Mutual redistribution

Major Problems

  • Firewall bottlenecks
  • Manual policy changes
  • Operational delays
  • Aging firewall hardware
  • High CPU utilization

💡 Critical CCDE Insight

The biggest problem is not routing.

The biggest problem is:

  • Operational friction
  • Change management delays
  • Cross-organizational approvals

This is extremely realistic in enterprise environments.

Operational Delay Formula

$$ Delay = Approvals + Implementation + Validation $$

11. Data Center Architecture

Jacobs DC

  • Collapsed core
  • OSPF Area 0
  • Firewall sandwich DMZ
  • Proxy-based Internet access

Toolmate DC

  • Collapsed core
  • EIGRP internally
  • Different firewall design
  • No proxy infrastructure

Architectural Issues

  • Different routing protocols
  • Different operational models
  • Different firewall behavior
  • Different Internet models

DC Scalability Formula

$$ Scalability \propto Bandwidth + Port\\ Density + Automation $$

12. Security Architecture Discussion

Security policy now mandates:

  • Single-function infrastructure devices
  • Physical separation of functions
  • No multifunction infrastructure

Why?

A previous virtualization interoperability issue caused a major outage.

This created organizational distrust toward converged infrastructure.

🎯 Real Enterprise Lesson

Technical decisions are often influenced by:

  • Historical outages
  • Organizational trauma
  • Executive perception
  • Risk tolerance

13. Office 365 and Cloud Challenges

Office 365 traffic currently traverses the DC Internet connection.

User experience is poor.

Why?

  • Hairpinning through DC
  • Increased latency
  • WAN congestion
  • Suboptimal SaaS routing

SaaS Optimization Formula

$$ User\\ Experience \propto \frac{1}{Latency} $$

As latency increases:

$$ Office365\\ Experience \downarrow $$

Potential Future Solutions

  • Local Internet breakout
  • SD-WAN
  • SaaS-aware routing
  • Cloud security edge

14. Capacity Planning Analysis

Jacobs Bluesky Utilization

  • 6–8Gbps peak utilization
  • Primary production WAN

Taco Utilization

  • 0.1–0.2Gbps only
  • Massively underutilized

Annet Utilization

  • 3–4Gbps peak
  • Moderate activity

ISP Utilization

  • Growing SaaS consumption
  • Increasing inbound cloud traffic

Capacity Utilization Formula

$$ Utilization = \frac{Traffic}{Provisioned\\ Bandwidth} \times 100 $$

For Taco:

$$ \frac{0.2}{10} \times 100 = 2\% $$

Meaning:

$$ 98\%\\ idle\\ capacity $$

15. Enterprise Networking Mathematics

Redundancy Formula

$$ Availability = 1 - (Failure_1 \times Failure_2) $$

QoS Delay Formula

$$ Delay = Serialization + Queuing + Propagation $$

Routing Scale Formula

$$ Control\\ Plane\\ Complexity \propto Routes + Peers $$

Firewall Throughput Formula

$$ CPU\\ Load \propto Sessions + Inspection + Throughput $$

Cloud Traffic Growth

$$ Cloud\\ Traffic_{2026} > Cloud\\ Traffic_{2025} $$

Enterprise cloud traffic growth is almost always exponential.

16. CLI and Routing Examples

VRRP Example

interface vlan10
 vrrp 10 ip 10.1.1.254

interface vlan10
 ip address 10.1.1.1 255.255.255.0

 vrrp 10 ip 10.1.1.254
 vrrp 10 priority 120
 vrrp 10 preempt
 vrrp 10 track GigabitEthernet0/0 decrement 50
VRRP Tracking Explanation

If the WAN uplink fails:

  • VRRP priority decreases
  • Backup router becomes active
  • Traffic fails over automatically

OSPF Example

router ospf 1
 network 10.0.0.0 0.255.255.255 area 0

router ospf 1
 router-id 1.1.1.1

 network 10.0.0.0 0.255.255.255 area 0

 passive-interface default
 no passive-interface GigabitEthernet0/0

17. CCDE-Level Architecture Thinking

This case study demonstrates that enterprise architecture is multidimensional.

The architect must evaluate:

  • Business priorities
  • Operational models
  • Existing technical debt
  • Political boundaries
  • Change management processes
  • Application behavior
  • Cloud adoption
  • Security constraints

💡 Most Important CCDE Lesson

The technically best solution is not always the correct enterprise solution.

The correct solution balances:

  • Business risk
  • Operational readiness
  • Migration complexity
  • Technical optimization

18. Key Takeaways

🎯 Key Learning Points

  • Acquisitions create operational fragmentation
  • MPLS backup links are underutilized
  • Cloud migration changes WAN requirements
  • Office 365 requires local Internet optimization
  • Firewall bottlenecks affect DCI scalability
  • Routing protocol diversity increases complexity
  • QoS remains critical for VoIP
  • Operational simplicity matters as much as technology
  • Security policies heavily influence architecture

Final Conclusion

Jacobs represents a realistic enterprise undergoing:

  • Business expansion
  • Cloud transformation
  • Network modernization
  • Operational rationalization

The environment demonstrates many real-world enterprise problems:

  • Multiple WAN providers
  • Acquisition-driven fragmentation
  • Aging infrastructure
  • Cloud transition pain
  • Operational bottlenecks
  • Security policy constraints

In future parts, we will analyze:

  • WAN redesign recommendations
  • Cloud optimization strategies
  • SD-WAN migration paths
  • Routing protocol modernization
  • Security segmentation redesign
  • DCI evolution
  • Internet breakout strategies
  • MPLS replacement options

This foundation is critical for understanding future CCDE-level design decisions.

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