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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

Prefix Subnet Interface/Node ID
32 to 56 bits 32 to 8 bits 64 bits

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

8 bits 4 bits 4 bits 112 bits
11111111 Flag Scope Group ID

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

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Comments

Hmm

"5 – site local" - sure it is 5? 4 would make sense imho.

"FC00::/7 – Unique Local Unicast"
So FC00 after all? I remember reading somewhere that they would make FC00, then that they would abandon FC00 for FD00 for local addresses (Jeremy Cioara told that in his CCNA videos, I think). And now it is FC00 again?

Adam's picture

From RFC 4193: "FC00::/7

From RFC 4193:

"FC00::/7 prefix to identify Local IPv6 unicast addresses."

Source: http://tools.ietf.org/html/rfc4193



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