IPv6 : Hop Limit field with traceroute6

ICMPv6, described in the IPv6 chapter of Computer Networking: Principles, Protocols and Practice is a companion protocol for IPv6 that is used for various functions including network debugging. traceroute6 is a popular debugging tool that allows to trace the path towards a destination.


Usage of Hop Limit by traceroute6

Can you infer the Hop Limit value of the packets captured during the following traceroute6:

traceroute6 -q 1 -n www.ietf.org
traceroute6: Warning: www.ietf.org.cdn.cloudflare.net has multiple addresses; using 2606:4700:10::6814:155
traceroute6 to www.ietf.org.cdn.cloudflare.net (2606:4700:10::6814:155) from 2a02:2788:484:59e:2c1c:849e:f74f:e233, 64 hops max, 12 byte packets
1  2a02:2788:484:59e:a221:b7ff:fed8:aa90  2.415 ms
2  2a02:2788:480::1  8.138 ms
3  2a02:2788:480:2::1  9.125 ms
4  2a02:2788:ffff:1b::1  9.757 ms
5  2001:7f8:26::a501:3335:1  7.960 ms
6  2400:cb00:78:1024::a29e:e959  7.934 ms
# Length Resumé Status
0 48 bytes <UDP: >  
1 48 bytes <UDP: >  
2 48 bytes <UDP: >  
3 48 bytes <UDP: >  
4 48 bytes <UDP: >  
5 48 bytes <UDP: >  

0000  6007d0ed001411??  2a0227880484059e  
0010  2c1c849ef74fe233  2606470000100000  
0020  0000000068140155  d182829b00141a84  

0000  `.Ðí...?*.'.....
0010  ,...÷Oâ3&.G.....
0020  ....h..UÑ.......
  • IPv6:
    • Version: 6
    • Traffic Class UB: 0
    • Traffic Class LB: 0
    • Flow Label UB: 7
    • Flow Label LB: 53485
    • Payload Length: 20
    • Next Header: 17
    • Hop Limit:
    • Source Address: 2a02:2788:484:59e:2c1c:849e:f74f:e233
    • Destination Address: 2606:4700:10::6814:155
    • Payload: UDP
      • Source Port: 53634
      • Destination Port: 33435
      • Length: 20
      • Checksum: 6788
0000  6007d0ed001411??  2a0227880484059e  
0010  2c1c849ef74fe233  2606470000100000  
0020  0000000068140155  d182829c00141170  

0000  `.Ðí...?*.'.....
0010  ,...÷Oâ3&.G.....
0020  ....h..UÑ......p
  • IPv6:
    • Version: 6
    • Traffic Class UB: 0
    • Traffic Class LB: 0
    • Flow Label UB: 7
    • Flow Label LB: 53485
    • Payload Length: 20
    • Next Header: 17
    • Hop Limit:
    • Source Address: 2a02:2788:484:59e:2c1c:849e:f74f:e233
    • Destination Address: 2606:4700:10::6814:155
    • Payload: UDP
      • Source Port: 53634
      • Destination Port: 33436
      • Length: 20
      • Checksum: 4464
0000  6007d0ed001411??  2a0227880484059e  
0010  2c1c849ef74fe233  2606470000100000  
0020  0000000068140155  d182829d0014f0b3  

0000  `.Ðí...?*.'.....
0010  ,...÷Oâ3&.G.....
0020  ....h..UÑ.....ð³
  • IPv6:
    • Version: 6
    • Traffic Class UB: 0
    • Traffic Class LB: 0
    • Flow Label UB: 7
    • Flow Label LB: 53485
    • Payload Length: 20
    • Next Header: 17
    • Hop Limit:
    • Source Address: 2a02:2788:484:59e:2c1c:849e:f74f:e233
    • Destination Address: 2606:4700:10::6814:155
    • Payload: UDP
      • Source Port: 53634
      • Destination Port: 33437
      • Length: 20
      • Checksum: 61619
0000  6007d0ed001411??  2a0227880484059e  
0010  2c1c849ef74fe233  2606470000100000  
0020  0000000068140155  d182829e0014cd01  

0000  `.Ðí...?*.'.....
0010  ,...÷Oâ3&.G.....
0020  ....h..UÑ.....Í.
  • IPv6:
    • Version: 6
    • Traffic Class UB: 0
    • Traffic Class LB: 0
    • Flow Label UB: 7
    • Flow Label LB: 53485
    • Payload Length: 20
    • Next Header: 17
    • Hop Limit:
    • Source Address: 2a02:2788:484:59e:2c1c:849e:f74f:e233
    • Destination Address: 2606:4700:10::6814:155
    • Payload: UDP
      • Source Port: 53634
      • Destination Port: 33438
      • Length: 20
      • Checksum: 52481
0000  6007d0ed001411??  2a0227880484059e  
0010  2c1c849ef74fe233  2606470000100000  
0020  0000000068140155  d182829f0014acdc  

0000  `.Ðí...?*.'.....
0010  ,...÷Oâ3&.G.....
0020  ....h..UÑ.....¬Ü
  • IPv6:
    • Version: 6
    • Traffic Class UB: 0
    • Traffic Class LB: 0
    • Flow Label UB: 7
    • Flow Label LB: 53485
    • Payload Length: 20
    • Next Header: 17
    • Hop Limit:
    • Source Address: 2a02:2788:484:59e:2c1c:849e:f74f:e233
    • Destination Address: 2606:4700:10::6814:155
    • Payload: UDP
      • Source Port: 53634
      • Destination Port: 33439
      • Length: 20
      • Checksum: 44252
0000  6007d0ed001411??  2a0227880484059e  
0010  2c1c849ef74fe233  2606470000100000  
0020  0000000068140155  d18282a000148b22  

0000  `.Ðí...?*.'.....
0010  ,...÷Oâ3&.G.....
0020  ....h..UÑ......"
  • IPv6:
    • Version: 6
    • Traffic Class UB: 0
    • Traffic Class LB: 0
    • Flow Label UB: 7
    • Flow Label LB: 53485
    • Payload Length: 20
    • Next Header: 17
    • Hop Limit:
    • Source Address: 2a02:2788:484:59e:2c1c:849e:f74f:e233
    • Destination Address: 2606:4700:10::6814:155
    • Payload: UDP
      • Source Port: 53634
      • Destination Port: 33440
      • Length: 20
      • Checksum: 35618

Information

Author(s) Olivier Bonaventure
Deadline No deadline
Submission limit No limitation
Category Tags IPv6

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