Multicast mac address

#1

whenever we use any kind of routing protocol they use some kind of multicast ip address to make neighborship and as well as routing table information.
for exampe
ospf-224.0.0.5/224.0.0.6
eigrp-224.0.0.10
rip-224.0.0.9
but i saw on packet tracer that they form some unique mac address which is called ip to mac mapping
like 01.00.5e.00.00.05 - ospf
my question is that how the router knows about this multicast mac address.
because each interface has particular nic card and each nic has his own mac address,
so, where does this multicast mac address get saved?
please help me

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#2

When routing protocol sends messages to each other they need L1 , L2 , L3 information as router works upto layer 3. So your ethernet frame is carrying packet and ethernet needs source and destination address.

So if you convert 224.0.0.5 in hexadecimal it’s 0100.5e.x.x.x

image

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