CCIE SP 400-201 V4.1 WRITTEN EXAM ESSENTIALS – Service Provider Architecture and Evolution

In a series of blog posts, I will go over each of the Cisco’s official blueprint sections for CCIE SP 400-201 V4.1 written exam and call out the very essential topics and knowledge base that are must-know for passing the exam. Please note that all of our CCIE Written Exam Cert Study Guides include similar exam essentials at the end of each chapter to reinforce key concepts for our readers.

I hope that you find them useful!

• While a PE router maintains VPN routing information, it is only required to maintain VPN routes for those VPNs to which it is directly attached.
• P routers are only required to maintain routes to the provider’s PE routers; they are not required to maintain a specific VPN routing information for each customer site.
  • The IOS-XR Microkernel is preemptive, and the scheduler is priority based
  • The following are the main functions of IOS-XR system manager:
  • Start processes during bootup or node reload
  • Start processes during route processor (RP) failover
  • Start processes in response to user configuration; for example, when a user configures an OSPF process using router ospf <process-name>, system manager starts a new OSPF process instance
  • Act as a central repository for all process-related information
  • Initiate disaster recovery based on the process health
  • Invoke dumper to collect a core dump when a process terminates abnormally
• A Hardware-Isolated Virtual Router (HVR) has hardware-based resource isolation between routing entities, whereas a Software-Isolated Virtual Router (SVR) comprises software-based resource isolation between routing entities
• SDRs provide full isolation between virtualized routing instances through the use of Distributed Route Processors (DRPs) for extra control plane resources.
• A Split Brain is a condition where the inter rack links between the routers in a Cisco ASR 9000 Series nV Edge system fails and hence the nodes on both routers start to act as primary node.
• The IRL (Inter-Rack Link) connections are required for forwarded traffic going from one chassis out of interface on the other chassis part of the nV edge system.
• In existing cellular networks, RAN backhaul is defined as the connection between the radio at the cell site and the radio controller.
• Although a Layer 2 system is good for timing with Synchronous Ethernet (SyncE), a Layer 3 system affords significantly more options for timing, including the most-requested 1588v2.