IPv6 for the CCIE R&S Candidate - Session Notes

Today I attended the IPv6 for CCIE R&S session presented by Johnny Bass, CCIE #6458 and Cisco 360 master instructor. Totally awesome presentation! I jotted some notes and figured I’d post them here to share.

All the content in the session (BRKCCIE-9592) is regarding the R&S 4.0 version blueprint. “If it’s not in the blueprint, it’s not in this session”

Different Addressing Types

• 2000::/3 – Global Unicast
• FC00::/7 – Unique Local Unicast
• FE80::/10 – Link Local Unicast
• FF00::/8 – Multicast

Note: The interface ID can be either EUI-64, use Privacy Extensions (RFC 3041), or locally configured.

Key Points for Link Local Addresses

• Assigned to all interfaces with IPv6 enabled on them
• Not Routable
• Recommend setting the link local for frame relay addresses so it’s easier to test in the lab; example: FE80::1 instead of FE80::2DD:1FF:FE1C:DB80
• Link local address are used to source ICMPv6 packets for neighbor discovery and stateless address autoconfiguration

If you only want a Link Local address:

    Interface GigabitEthern0/1
        Ipv6 enable

If you want to set your own:

    Interface GigabitEthern0/1
        Ipv6 address FE80::5 link-local

Key Points for Unique Local Addresses

• Replaces Site Local Addresses
• RFC 4193
• Not to be advertised on the Internet
• Not exactly like RFC1918 IPv4 addresses, but similar

Key points for Multicast Addresses

• FF00::/8

Recommend setting the first 80 bits of the Group ID to 0 and only use the last 32 bits
Gives you over 4 billion groups to choose from...

• Flag bits – Only the lease significant bit is currently used:
•  0 is a well known multicast
• 1 is not permanent (a.k.a transient multicast)
• Scope
• 1- node local
• 2 – link local
• 5 – site local
• 8 – organization local
• E (14) – Global

Assigning Addresses

• Static
• Ipv6 address 2005:DEAD:BEEF::1/64
• DHCPv6
• Ipv6 address dhcp
• No broadcast in v6, so use address: FF02::1:2
• Stateless auto configure
• Ipv6 address autoconfig

Stateless Address Autoconfigure (SLAAC)

• Uses ICMPv6 router discovery
• Router responds with
• prefix for the link
• default gateway
• Options (lifetime of advertisement)
• MTU
• Prefix Length
• Router Priority
• Host completes the address with either a preconfigured host portion, privacy extensions, or EUI-64

Router Solicitation

•     ICMP type 133
•     Source ::
•     Destination FF02::2

Router Advertisement

•     ICMP type 134
•     Source -  router link local address
•     Destination – FF02::1

Common IPv6 Addresses

• ::1 (loopback)
• :: (undefined)
• FE80::/10 (link local)
•  ::/0 (default)
•  FF02::/16 (link local multicast)
•  FF02::1 (all local nodes)
•  FF02::2 (all local routers)
•  FF02::5 & 6 (OSPFv3)
•  FF02::9 (RIPng)
•  FF02::A (EIGRPv6)

Note: The conversion of layer 3 multicast to layer 2 is to take the last 32 bits of the IPv6 address and prepend 33 33.

First Hop Redundancy Protocols

• IPv6 has HSRP and GLBP
• HSRP has one active forwarding device
• GLBP has four active forwarding devices
• Priority is to elect the Active Virtual Gateway (the boss)
• Weight is for the Active Virtual Forwarder
• If weight drops below the set acceptable range, the AVF stops forwarding

DNS updated for IPv6

• AAAA record for 128 bit addresses
• Still uses PTR records for reverse lookups, but there’s a new nibble format
• Current recommendation is to not auto-generate PTR records

Static Routes in IPv6
Directly attached Static Routes

    ipv6 route 2005:DEAD:BEEF:A100::/64 Serial0/1

Recursive Static Routes

ipv6 route 2005:DEAD:BEEF:A100::/64 2005:DEAD:BEEF:C100::1  !address only

Fully Specific Static Routes

ipv6 route 2005:DEAD:BEEF:A100::/64 GigabitEthernet0/1 2005:DEAD:BEEF:C100::1

Floating Static Routes

ipv6 route 2005:DEAD:BEEF:A100::/64 2005:DEAD:BEEF:C100::1 130

Key Points for OSPFv3

• Two LSA’s have been renamed:
• Type 3 LSA is now Interarea Prefix LSA
• Type 4 LSA is now Interarea Router LSA
• Two new LSAs have been added
• Type 8 LSA is now Link LSA
• Type 9 LSA is now Intra-Area Prefix LSA

Note: When no IPv4 addresses are available you must configure a router-id manually