IPv6: Passing on Lessons Learned from My Journey BRKARC-2002 Denise “Fish” Fishburne Customer Proof of Concept Team Lead CCIE #2639, CCDE 2009:0014

© 2015 Cisco and/or its affiliates. All rights reserved. Cisco PublicBRKARC-2002 Agenda Show a Magic Trick Explain How the Magic Trick works Resolving the destination MAC

© 2015 Cisco and/or its affiliates. All rights reserved. Cisco PublicBRKARC The Magic Trick

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© 2015 Cisco and/or its affiliates. All rights reserved. Cisco PublicBRKARC How The Magic Trick Works

6 FF02::5 FE80::2237:6ff:fecf:67e4 FE80::5a0a:20ff:feeb:91e4 FE80::2237:6ff:fecf:67e4 FE80::5a0a:20ff:feeb:91e4 How the Magic Trick Works

7 FF02::5 How the Magic Trick Works MULTICAST

8 How the Magic Trick Works

9 Multicast Local: They are local to the wire they are on. Common interest: If a router wants to participate in EIGRP, it already knows the local multicast address (IPv4/IPv6) to start to listen to and the corresponding MAC address. Join: “Join” just by just deciding to listen to a local multicast address and then, by extension, to the corresponding MAC address for that multicast IP address. “Link Local” Multicast Exists in IPv4 & IPv6

10 Link-Local Scope Multicast Address

11 Link-Local Scope Multicast Address Multicast Local: They are local to the wire they are on. Common interest: If a router wants to participate in EIGRP, it already knows the local multicast address (IPv4) to start to listen to and the corresponding MAC address. Join: “Join” just by just deciding to listen to a local multicast address and then, by extension, to the corresponding MAC address for that multicast IP address.

12 Link-Local Scope Multicast Address

13 Link-Local Scope Multicast Address

14 Link-Local Scope Multicast Address Multicast Local: They are local to the wire they are on. Common interest: If a router wants to participate in EIGRP, it already knows the local multicast address (IPv6) to start to listen to and the corresponding MAC address. Join: “Join” just by just deciding to listen to a local multicast address and then, by extension, to the corresponding MAC address for that multicast IP address.

15 Link-Local Scope Multicast Address

16 Link-Local Scope Multicast Address

17 FE80::2237:6ff:fecf:67e4 FE80::5a0a:20ff:feeb:91e4 How the Magic Trick Works

18 FE80::2237:6ff:fecf:67e4 FE80::5a0a:20ff:feeb:91e4 How the Magic Trick Works

19 How the Magic Trick Works “Link Local” Unicast

20 How the Magic Trick Works

21 How the Magic Trick Works

22 Puzzle Piece: Link-Local Address “In the Internet Protocol Version 6 (IPv6), the address block fe80::/10 has been reserved for link-local unicast addressing. The actual link local addresses are assigned with the prefix fe80::/64. They may be assigned by automatic (stateless) or stateful (e.g. manual) mechanisms. Unlike IPv4, IPv6 requires a link-local address to be assigned to every network interface on which the IPv6 protocol is enabled, even when one or more routable addresses are also assigned. Consequently, IPv6 hosts usually have more than one IPv6 address assigned to each of their IPv6-enabled network interfaces. The link-local address is required for IPv6 sublayer operations of the Neighbor Discovery Protocol, as well as for some other IPv6-based protocols, like DHCPv6.” Wikipedia

23 How the Magic Trick Works

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© 2015 Cisco and/or its affiliates. All rights reserved. Cisco PublicBRKARC Resolving Destination MAC Address

© 2015 Cisco and/or its affiliates. All rights reserved. Cisco PublicBRKARC IPv4 w/ Broadcasts

© 2015 Cisco and/or its affiliates. All rights reserved. Cisco PublicBRKARC How Does this Work without Broadcast and ARP?

28 Resolving Destination MAC Address

29 Resolving Destination MAC Address

30 Resolving Destination MAC Address

© 2015 Cisco and/or its affiliates. All rights reserved. Cisco PublicBRKARC Solicited-Node Multicast

32 A node is required to compute and join (on the appropriate interface) the associated solicited-node multicast addresses for all unicast and anycast addresses that have been configured for the node's interfaces (manually or automatically). Solicited-Node Address: FF02:0:0:0:0:1:FFXX:XXXX Solicited-node multicast address are computed as a function of a node's unicast and anycast addresses. For example, the solicited-node multicast address corresponding to the IPv6 address 4037::01:800:200E:8C6C is FF02::1:FF0E:8C6C. Snippets from RFC4291 section 2.7 Solicited-Node Multicast

33 Solicited-Node Address: FF02:0:0:0:0:1:FFXX:XXXX Solicited-Node Multicast

34 Solicited-node multicast address are computed as a function of a node's unicast and anycast addresses. For example, the solicited-node multicast address corresponding to the IPv6 address 4037::01:800:200E:8C6C is FF02::1:FF0E:8C6C. Snippets from RFC4291 section 2.7 Solicited-Node Multicast

35 Solicited-Node Multicast

36 Solicited-Node Multicast

37 Solicited-Node Multicast

© 2015 Cisco and/or its affiliates. All rights reserved. Cisco PublicBRKARC Neighbor Discovery Protocol

© 2015 Cisco and/or its affiliates. All rights reserved. Cisco PublicBRKARC Neighbor Discovery Protocol

40 Neighbor Discovery Protocol