About Me
Cisco Certified Network Professional (CCNP) - Enterprise
1 Introduction to Enterprise Networks
1-1 Enterprise Network Architecture
1-2 Network Design Principles
1-3 Network Security in Enterprise Environments
1-4 Network Management and Monitoring
2 Network Infrastructure
2-1 Cabling and Connectivity
2-2 Network Topologies
2-3 Network Devices (Switches, Routers, Firewalls)
2-4 Network Addressing (IP, Subnetting)
3 Switching Technologies
3-1 Layer 2 Switching
3-2 VLANs and Trunking
3-3 Spanning Tree Protocol (STP)
3-4 EtherChannel and Link Aggregation
3-5 Virtual Switching Systems (VSS)
4 Routing Technologies
4-1 Static Routing
4-2 Dynamic Routing Protocols (RIP, EIGRP, OSPF, BGP)
4-3 Route Redistribution and Filtering
4-4 IPv6 Routing
4-5 Policy-Based Routing (PBR)
5 Network Automation and Programmability
5-1 Introduction to Network Automation
5-2 Python for Network Automation
5-3 RESTful APIs and NETCONFYANG
5-4 Ansible for Network Automation
5-5 Network Programmability with Cisco DNA Center
6 Network Security
6-1 Network Security Fundamentals
6-2 Access Control Lists (ACLs)
6-3 Intrusion Detection and Prevention Systems (IDSIPS)
6-4 Virtual Private Networks (VPNs)
6-5 Firewalls and Security Zones
7 Wireless Networking
7-1 Wireless LAN Fundamentals
7-2 Wireless Security Protocols (WPA, WPA2, WPA3)
7-3 Wireless Site Surveys
7-4 Wireless Network Design
7-5 Wireless Network Management
8 Network Services
8-1 DHCP and DNS
8-2 Network Time Protocol (NTP)
8-3 Quality of Service (QoS)
8-4 Network Address Translation (NAT)
8-5 Network Management Protocols (SNMP, Syslog)
9 Network Troubleshooting
9-1 Troubleshooting Methodologies
9-2 Common Network Issues
9-3 Troubleshooting Tools (Ping, Traceroute, Wireshark)
9-4 Troubleshooting Wireless Networks
9-5 Troubleshooting Security Issues
10 Enterprise Network Design
10-1 Network Design Models (Hub-and-Spoke, Mesh)
10-2 Network Redundancy and High Availability
10-3 Network Scalability and Performance
10-4 Network Documentation and Diagrams
10-5 Case Studies and Real-World Scenarios
4.5 Policy-Based Routing (PBR)

4.5 Policy-Based Routing (PBR)

Key Concepts

Policy-Based Routing (PBR)

Policy-Based Routing (PBR) is a method of controlling the path that data packets take through a network based on specific policies rather than traditional routing protocols. PBR allows administrators to define rules that determine how packets are forwarded, providing greater flexibility and control over network traffic.

Match Criteria

Match Criteria are the conditions that determine whether a packet should be subject to PBR. These criteria can include source IP address, destination IP address, protocol type, and more. When a packet matches the specified criteria, it is processed according to the defined PBR policy.

Example: Imagine a security guard at a gate who checks incoming vehicles. The guard has specific criteria (e.g., vehicle type, license plate) to decide whether to allow the vehicle through. Similarly, PBR uses match criteria to decide which packets to route differently.

Set Actions

Set Actions are the instructions that define what happens to packets that match the PBR criteria. These actions can include changing the next-hop IP address, modifying the outgoing interface, or applying specific QoS policies. Set Actions ensure that packets are directed according to the defined policies.

Example: Consider a traffic officer directing cars to different lanes based on their destination. The officer's actions (e.g., pointing to a specific lane) determine the path the cars take. In PBR, set actions determine the path packets take through the network.

Precedence

Precedence refers to the order in which PBR policies are applied. When multiple policies are defined, the order of precedence is crucial. Policies with higher precedence are applied first, and if a packet matches multiple policies, the one with the highest precedence takes effect.

Example: Think of a priority system in a hospital where emergency cases are treated first. The highest priority cases (policies) are handled before others. In PBR, precedence ensures that critical policies are applied before less important ones.

Conclusion

Policy-Based Routing (PBR) offers a powerful way to manage network traffic by applying specific policies to packets based on match criteria. By defining set actions and ensuring proper precedence, administrators can control the flow of data through their network, enhancing performance, security, and flexibility.

© 2024 Ahmed Baheeg Khorshid. All rights reserved.