1. Internet Protocol Version 6
Solicited Node Multicast

2. Recap – IPV4 Address Resolution Protocol
Assume 30 nodes in a network of IP –
Initially each node is unknown to other.
Now, Node want to communicate to It does not know the destination node mac
builds a ARP packet with src ip destination ip ;src mac address and destination mac address FF:FF:FF:FF:FF:FF (broadcast)
Hey ALL in the subnet respond to me
All nodes in the segment need to process the ARP packet, NOT AN EFFICIENT METHOD
Recap – IPV4 Address Resolution Protocol

3. IPV4 Address Resolution Protocol is not an efficient method
Eliminate the broadcast method, adapt multicasting for neighbor discovery. What next ?
Challenges of IPv6 protocol design group ?
In a broadcast network type, how do I limit neighbor discovery to a specific group?
If I miss one in the segment?
What is the IPv6 neighbor discovery strategy?
A source node knows the destination IPv6 address? Yes
If a source node could derive/GUESS the multicast IPv6 from the known destination IPv6 address will it suffice the need - Yes
How to implement the strategy?
When IPv6 is activated in an interface of node, let the interface also get assigned AUTOMATICALLY with an another address derived from its own IPv6 Address ?
Call it as “Solicited Multicast Address” as it helps neighbor solicitation
IP Version 6

4. Solicited Node Multicast Address
Assigned with IPv6 Address 2001::/64
MAC Address
Expanded EUI-64 IPv6 Address
2001:0:0:0:200:FF00:FE00:0001
Rules of Solicited Node Multicast Address
Prefix of all solicited node multicast address is ff02::1:ff_ _:_ _ _ _/104
Derive the remaining 24 bits from the IPv6 address.
Last 24 bits are used to arrive 128 bit IPv6 solicited multicast
So, solicited multicast address of Node 1
ff02::1:ff00:1
Solicited Node Multicast Address

5. Neighbor Discovery with Solicited Multicast Address
Node2’s knowledge
My IPv6 Address
My MAC Address
Destination(Node 1) IPv6 Address
Node 1 MAC address to be discovered
Node2’s Neighbor(Node1) Discovery
Let me guess Node 1 Solicited Node Multicast Address as I know its IPv6 Address of Node2
Apply Solicited Node Multicast Address rules as said the earlier slide
Found ff02::1:ff00:1
Node2’s Discovery of Node 1
Possibilities are there more than one node of address ff02::1:ff00:1 exist in the network since it is a GUESS
Is it broadcast or multicast or uni-cast
Theoretically it is not a broadcast, but in reality it is
Ideally it is uni-cast, but it can become a MULTICAST when more than one node exist of address ff02::1:ff00:1 by accident
Further areas to explore
IPv6 protocol is build with resilience to embrace Multicast with ease, provided we create an environment for it
Adaption of IPv6 at Layer 2 is required hand in hand
Multicast Listener Discovery (MLD) snooping an example
Neighbor Discovery with Solicited Multicast Address