Skip to content

IPV6 Neighbor Discovery Protocol

In ipv6 we don't have ARP but we do have Neighbor Discovery Protocol.

  • Neighbor Table

Broadcast vs Multicast (Layer 2)

  • Broadcast message is a message of all F's in it's Destination MAC address field. (Respect)
    • When we have all F's in the dest mac addres field, and it reaches the switch it will broadcast to all active interfaces.

Multicast (ipv6)

  • IGMP - Internet Group Management Protocol

  • Router Advertisement

    • Router MAC Address
    • Network Prefix/mask
    • Client IPv6 address options

  • Neighbor Advertisement

    • Client MAC Address
    • Client IPv6 Address
    • Options

  • Devices maintain IPv6 neighbor table

    • IPv6 address -> MAC Address
  • Use Neighbor Solicitation to request missing information

  • Behaves similar to ARP

  • Show ARP

    • arp -a
  • Show Negihbor Table
    • Microsoft
      • netsh int ipv6 show neighbor
    • Linux
      • ìp -6 neigh show

Case

1
2
3
4
5
Dev1 - 2001:DB8:A::y/64
Dev2 - 2001:DB8:A::x/64
Router - 2001:DB8:A::1/64

Dev1,2 --- [Switch] ---(F0/0) Router

Router

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
en
shopw ip int bri
conf t

int f0/0 # interface f0/0
ipv6 address 2001:DB8:a::1/64  # ipv6 on int f0/0
exit

show ipv6 int bri

int f0/0
ipv6 address fe80::1 link-local
exit
exit
show ipv6 int bri