Advanced Routing and Traffic Engineering Questions
Advanced routing protocols, algorithms, and real world deployment practices for large scale and multi domain networks. Topics include deep Border Gateway Protocol knowledge such as path selection, attribute handling including weight, local preference, AS path manipulation, multi exit discriminators, communities, route filtering, route aggregation, and mitigation of route hijacking. Also covers advanced aspects of interior protocols such as Open Shortest Path First and IS IS including area design, adjacency and LSA or link state behavior, convergence optimization, and comparison of link state versus other approaches. Traffic engineering topics include load balancing, multi path routing, MPLS fundamentals and label switching, segment routing principles, and using routing and BGP for traffic engineering across internet exchanges and multi carrier environments. Practical skills include designing redundancy, scaling routing control planes, route policy design, and troubleshooting complex inter domain routing behaviors.
MediumTechnical
48 practiced
Compare link-state IGPs (OSPF/IS-IS) versus BGP in terms of convergence behavior and scaling in a large service provider network. Discuss SPF computation costs, iBGP scaling challenges, path exploration, and specific tuning techniques used to improve convergence for both IGP and BGP (e.g., LSA throttling, incremental SPF, BGP MED damping, BFD).
MediumTechnical
34 practiced
Describe how MPLS Traffic Engineering using RSVP-TE works end-to-end. Include the LSP lifecycle: path computation (PCE or local), RSVP PATH and RESV messages, bandwidth reservation, label allocation, and how local and global repair mechanisms (FRR, RSVP re-optimization) are used to provide protection and fast convergence.
EasyTechnical
62 practiced
What are BGP communities and how are they used operationally? Explain standard versus extended communities, give concrete examples such as no-export, no-advertise, peer-specific IX communities or blackhole communities, and describe typical use cases like inbound traffic engineering, selective announcements, and emergency blackholing.
HardBehavioral
42 practiced
Tell me about a time you led a cross-functional team to resolve a multi-day inter-domain routing outage affecting customers. Walk through the timeline, the technical and non-technical actions you directed (escalation to peers, temporary mitigations, customer communication), how you coordinated ISPs/IXPs, the root cause analysis outcome, and the post-incident changes you implemented to prevent recurrence.
HardTechnical
42 practiced
Design and describe an automated system to detect and mitigate BGP prefix hijacks in real time for your network. Include RPKI ROA publishing, RTR-based validation, correlation with public BGP feeds (bgpstream), alerting/triage logic, automated mitigation options (community-based remote filtering, prepending to withdraw, contacting peers), the risk of false positives (and rollback), and coordination with IXPs and transit providers.
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