Virtual Routers vs. Logical Routers in Palo Alto Networks Firewalls

Overview

Palo Alto Networks firewalls support two types of routing engines: the legacy engine using Virtual Routers (VRs) and the Advanced Routing Engine using Logical Routers (LRs) . While both serve to manage Layer 3 routing, they differ in functionality and configuration.

Virtual Routers (Legacy Routing Engine)

• Created by default on the firewall.
• Each VR maintains its own separate routing table.
• Routing profiles (e.g., for BGP, OSPF) are unique to each VR and not shared.
• Suitable for simpler network environments with basic routing requirements.

Logical Routers (Advanced Routing Engine)

• Not created by default; must be manually configured.
• Allow for more granular and scalable routing configurations.
• Support shared routing profiles across multiple LRs within the same virtual system, promoting reusability and consistency.
• Enable advanced features like route maps, prefix lists, and policy-based redistribution.
• Facilitate dynamic routing between LRs using loopback interfaces and static routes pointing to other LRs.

Key Differences

Feature	Virtual Router	Logical Router
Creation	Automatic	Manual
Routing Profile Sharing	No	Yes
Advanced Routing Features	Limited	Extensive
Inter-Router Communication	Requires external interfaces	Supported via loopback interfaces and static routes

Considerations

• Transitioning from VRs to LRs requires enabling the Advanced Routing Engine and may necessitate configuration adjustments.
• Not all features are automatically migrated; careful planning is essential to ensure a smooth transition.
• Logical Routers are better suited for complex network topologies requiring advanced routing capabilities.

Additional Resources

• Legacy vs. Advanced Routing Engine
• Logical Router Overview
• Dynamic Routing between Logical Routers