Abstract

Network operators need to understand how routing affects their customers, and to quickly detect routing changes. Despite its importance, today, there is no good way to summarize routing for a service, nor to differentiate between tiny changes and huge shifts. It is challenging to understand routing, even for a single destination, because no one organization has a global view of routing —routing emerges from combining the Internet's diverse routing policies as determined by business and policy constraints. We present Fenrir, a new tool that can rediscover recurring routing results. It can help operators detect routing modes (stable periods) and spot changes that need a performance check. We use Fenrir to evaluate B-Root's anycast service to show routing dynamics over five years. Fenrir shows that the routing of B Root is relatively stable except when sites are removed or added to B Root DNS service.

Date

2025

Authors

Xiao Song, John Heidemann

Book

Proceedings of the 2025 ACM Internet Measurement Conference

Pages

1074-1075