Nokia Lab | LAB 3 IS-IS |


Hello everyone!

It's the next Nokia lab. Today we will review routing protocol widely spread across service providers networks. 
Please check my first lab for input information.

Topology example



















Lab tasks and questions:
  • Basic IS-IS
    • configure IS-IS between R1 and R2 (use P2P interface type, Level 2 only, "system" interface as passive, area 49.01)
      • check neighbors state
        • examine IS-IS control plane PDUs (You can use debug or packet capture)
          • describe all IS-IS PDU and their purpose
          • What transport does IS-IS use for control plane PDU delivery? Any difference with OSPF?
            • Examine destination MAC address of control plane PDU
    • examine LSDB
      • examine LSP in detail
        • What TLV types does it contain? Examine every TLV
    • examine route table
      • What is the default preference of IS-IS routes?
      • What is max-metric of IS-IS routes (default configuration)?
        • How to change behavior? How to take into account link bandwidth? 
  • Multi-area IS-IS
    • configure R3 and R4 as L1/L2 IS-IS routers (use P2P interface type, area 49.02)
    • configure R5 and R6 as L1-only IS-IS routers (use P2P interface type, area 49.02)
      • check IS-IS adjacency on R3
        • What adjacency types do you see?
      • examine LSDB on R3
        • make attention to LSP attributes
          • Is there ATT bit? What is the main purpose of ATT bit?
            • Check route table on R5 or R6
              • Does it contain default route?
      • check reachability between "system" interfaces of R5 and R2
        • Describe control plane process:
          • LSP exchange between IS-IS levels
          • route-table manager actions
        • Simulate situation with suboptimal routing (e.g. change metric on links R1-R3, R3-R4)
          • run traceroute from R2 to R5 and vice versa
            • compare outputs
  • Summarization and external routes
    • create two loopback interfaces on R1 with addresses from the same subnet
      • add interfaces to IS-IS as passive
      • summarize them on R1
        • check route-table on R1 and R2
          • find summary prefix
        • examine LSP on R1
          • find summary prefix
    • create loopback interface on R2 and export it to IS-IS by policy
      • examine R2 LSP
        • What is TLV contain our external prefix?
      • add route tag to external route by policy
        • examine R2 LSP again
        • What is the main purpose of route tags?
  • Multi-topology
    • make sure that all routers have ipv6 configuration ("system" interface, P2P interfaces, and so on)
    • enable IS-IS multi-topology option
    • enable multi-topology ipv6 routing
      • examine IS-IS database in detail
        • describe new TLV and their purpose
Final configs
Github project

Useful debug commands
show router isis adjacency {detail}
show router isis database {detail}
show router isis interface

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