Hello David
The best practice for advertising networks into BGP largely depends on your specific network design and requirements. Both the network and redistribute commands have their uses, but they operate differently.
The network command in BGP is used to advertise networks that are already present in the routing table. It’s a good practice to use this command when you want to have granular control over which routes are being advertised. This method requires more configuration as you would need to manually specify each network that you wish to advertise.
On the other hand, the redistribute command is used to take routes from other routing protocols and inject them into BGP. This is a more automated way of advertising routes, as it doesn’t require manual configuration for each network. Although the redistribute command requires that the redistributed prefixes be in the routing table, it doesn’t require an exact match as the network command does. However, it can potentially lead to the advertisement of unwanted routes if not properly controlled, which may cause routing loops or other issues.
Keep in mind that using the ‘redistribute’ command without proper route filtering can lead to the propagation of unnecessary routes, which can increase the size of the routing table and use more resources. It could also inadvertently advertise routes that you do not want to advertise.
So, if you have a small to medium-sized network where you can easily manage and control all your routes, you might prefer using the ‘network’ command. If you have a large network with many dynamic routes, then ‘redistribute’ might be more efficient, but you should be careful to apply appropriate filtering.
Always consider your network’s specific requirements and constraints when choosing between these methods.
I hope this has been helpful!
Laz