One problem with UIs for displaying routes is that routers' scale varies wildly: a home router may have just a handful of routes, while an ISP edge will have millions. For this reason, always requesting the full table is infeasible: if the router is an ISP edge, that will overload the client with a lot of data.

Clients thus should have a way to see how many routes are there and make informed decisions whether to request the complete routing table or limit themselves to specific queries or paginated views (when pagination is available in FRR).

(One reason why a paginated view is not a universal solution is that routing tables are not always static and requesting data page by page when the source data is changing can create really funny consistency problems, so clients need to choose between requesting a large amount of consistent data at once or a paginated but possible inconsistent view)