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Spirent TestCenter: STC generates IPv6 multicast stream with destination MAC address same as OSPFv3 MAC address

Environment/Versions
  • STC 4.36
  • IPv6 Multicast Stream generation
  • When trying to generate IPv6 multicast stream, STC will automatically map the IPv6 multicast address to MAC address.
  • Example: IPv6 Multicast address ff1e:190::5 or ff1e:190::6, STC will generate MAC address as: 33:33:00:00:00:05 and 33:33:00:00:00:06, which is same as OSPFv3 MAC address defined by IETF.

 

Answer
  • This may confuse customer, suspecting STC is doing this incorrectly.
  • According to the IPv6 Multicast address to MAC address mapping procedure, STC is actually correct.
  • RFC 3307 
    4.3  Dynamic IPv6 Multicast Addresses
         Dynamic IPv6 multicast addresses can be allocated by an allocation server or by an end-host.  Regardless of the allocation mechanism, all dynamically allocated IPv6 multicast addresses MUST have the T bit set to 1.  This will distinguish the dynamically allocated addresses from the permanently assigned multicast addresses, defined in [RFC 2375], at the link-layer on any media that maps the lower portion of the IPv6 multicast address into a link-layer address. It should be noted that the high-order bit of the Group ID will be the same value as the T flag. As an example, the permanent IPv6 multicast address FF02::9 maps to an Ethernet group address of 33-33-00-00-00-09.  A dynamically allocated IPv6 multicast address of FF32::8000:9 would map to the Ethernet group address 33-33-80-00-00-09.

 

Product : Multicast