Good morning,
We are preparing to replace our BGP router. We currently have a BGP session with a single provider. We advertise our address space and we receive nearly 1 million IPv4 routes and 200000 ipv6 routes.
They system runs on a CCR1009 and has been providing us with good service.
However, I am not sure what the purpose of importing these routes are, as we only have a single exit point: the gateway for all routes is the same.
In the new router I am planning to filter out all incoming routes, except the default gateway.
Am I missing something?
Thanks!
Ask your operator to send you only its own prefixes.
Or you can use NLRI filtering on the MikroTik to only allow 0.0.0.0/0. There may come a time when you get a second provider and want to start using those BGP routes for egress decisions.
Thank you.
Indeed - I was planning to reject all received routes except the default gateway.
I can see no use for them while we have a single provider, but I was just wondering if there might be unexpected side effects.
Still, by today’s standards, our router is not at all top of the line. But it does not seem to have suffered from all these (unused) routes.
The memory (2 Gb) shows at 65%, CPU load is about 25%.
I was wondering if the routing/forwarding tables are used for each packet to determine the next hop, even if the outcome is known in advance.
I can’t imagine having hundreds or thousands of routes being helpful. Sure, there are optimizations in the routing tree so that packets aren’t compared against each route, but I would still recommend filtering out what you know for sure you’re not going to use (basically everything).
The profiler (under Tools) will give you an idea of how much CPU time is spent in routing.