100-105 Video025 IPv6 (does not use broadcast)

Hi,
I am a bit confused and hoping I can get some help, in the above video Keith talks about arp requests at layer3 to get mac address for layer 2 communications, to do this a layer2 broadcast is created on the network (layer 2 frame sent to ffff:ffff:ffff), the video then goes on to say that ipv6 doesn't use broadcasts and to get the same information (mac address for layer 2 communications) a Solicited node multicast packet is sent to the address that was given in the router advertisement. The but I don't understand is arp uses a layer 2 broadcast to communicate at layer 2 (at least to start with) what is happening at layer2 for ipv6 and why is it different and how does it not use broadcasts? or am I just missing something ?

Thanks in advance, (hope my terminology makes sense)
Stuart.

Answers

  • A1- That's correct ipv6 doesn't use broadcast that's how it was design.
    A2- ARP is layer 2. The reason being is that a broadcast is sent on layer 2 (data link layer) and ARP will normally not traverse to layer 3 (network layer). However it can provide extra features to the layer 3 protocol. The truth is that not all protocols fit the OSI model exactly, because after all it's just a model.

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