What routing mistakes should you avoid?

1 Wrong or outdated routing table

One of the most basic and frequent routing mistakes is having a wrong or outdated routing table. A routing table is a database that stores the best paths to reach different networks, based on metrics such as distance, cost, or bandwidth. If the routing table is not updated when the network topology changes, or if it contains incorrect entries due to misconfiguration or malicious attacks, the packets may be sent to the wrong destination, dropped, or looped. To avoid this mistake, you should use dynamic routing protocols that can automatically adjust the routing table according to the network conditions, such as OSPF, EIGRP, or BGP. You should also verify and monitor your routing table regularly, using commands such as show ip route or traceroute .

2 Suboptimal routing policy

Another common routing mistake is having a suboptimal routing policy. A routing policy is a set of rules that determines how the router selects the best path among multiple available paths, based on criteria such as preference, weight, or local preference. A suboptimal routing policy can result in poor performance, congestion, or inefficiency in the network. For example, if you use a routing policy that favors the shortest path, you may ignore other factors such as traffic load, reliability, or latency. To avoid this mistake, you should design and implement a routing policy that meets your network objectives and requirements, such as load balancing, redundancy, or quality of service. You should also test and evaluate your routing policy periodically, using tools such as ping or show ip bgp .

3 Inconsistent or conflicting routing protocols

A third common routing mistake is having inconsistent or conflicting routing protocols. A routing protocol is a set of rules and algorithms that routers use to exchange routing information and update their routing tables. If you use different routing protocols in different parts of your network, or if you use the same routing protocol with different parameters or configurations, you may create inconsistency or conflict in your routing information. For example, if you use RIP in one segment and OSPF in another segment, you may have different hop counts or metrics for the same destination. To avoid this mistake, you should use a consistent and compatible routing protocol across your network, or use a routing protocol that can interoperate with other routing protocols, such as BGP. You should also use route redistribution carefully and selectively, to avoid creating loops or duplicating routes.

4 Inadequate or improper security measures

A fourth common routing mistake is having inadequate or improper security measures. Routing is vulnerable to various types of attacks, such as spoofing, hijacking, or denial of service. If you do not secure your routing information and devices, you may compromise your network integrity, availability, or confidentiality. For example, if you do not authenticate your routing updates, an attacker may inject false or malicious routes into your routing table, diverting or blocking your traffic. To avoid this mistake, you should use security features and best practices, such as encryption, authentication, filtering, or logging. You should also update and patch your routing software and hardware regularly, to prevent exploits or vulnerabilities.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?