IPv6 Addressing and Deployment Considerations

IPv6
Introduction and Deployment Considerations
Md. Abdul Awal
BdREN
awal@bdren.net.bd
TEIN Application Workshop 2017
University of Dhaka
December 13, 2017
These materials are licensed under the Creative Commons Attribution-NonCommercial 4.0
International license. https://creativecommons.org/licenses/by-nc/4.0/

Agenda
• IPv6 Intro
• Subnetting
• IPv6 Plan
• Lab
• Discussion
TEIN Application Workshop 2017, University of Dhakaawal@bdren.net.bd 2

Protocol Header Comparison

IPv6 Address Format
• 128 bits or 16 bytes long
• 2^8 or 3.4E+38 possible addresses
• 5*E+28 address per person on earth
• 128 binary bit is reduced down to 32 hex bit
• 16 bit number is converted to a 4 digit hexadecimal
number in each field
• Also called “Nibble” boundaries
• “Coloned Hex” format: X:X:X:X:X:X:X:X (X = 16 bit
hexadecimal field)
• Separated by colon (:)
• Case-insensitive for hexadecimal digits A-F

IPv6 Address Representation
2031:0000:130F:0000:0000:09C0:876A:130B2031:0000:130F:0000:0000:09C0:876A:130B
2031: 0:130F: 0: 0: 9C0:876A:130B
2031:0:130F:0:0:9C0:876A:130B2031:0:130F:0:0:9C0:876A:130B
2031:0:130F::9C0:876A:130B
Rule 1: Leading zeroes
within a 16-bit value
may be omitted
Rule 2: Only a single
occurrence of consecutive
groups of zeroes may be
replaced by a double colon (::)

IPv6 Address Examples
FF01:0:0:0:0:0:0:1 = FF01::1
E3D7:0000:0000:0000:51F4:00C8:C0A8:6420
= E3D7::51F4:C8:C0A8:6420
3FFE:0501:0008:0000:0260:97FF:FE40:EFAB
= 3FFE:501:8:0:260:97FF:FE40:EFAB
= 3FFE:501:8::260:97FF:FE40:EFAB
FF01:0000:0000:0000:0000:0000:0000:1

IPv6 Addressing Model
• IPv6 Address type
• Unicast
• An identifier for a single interface
• Anycast
• An identifier for a set of interfaces
• Multicast
• An identifier for a group of nodes
RFC
4291

Different IPv6 Addresses
IPv6 Address Description
::/0
• All routes and used when specifying a default static route.
• It is equivalent to the IPv4 quad-zero (0.0.0.0).
::/128
• Unspecified address and is initially assigned to a host
when it first resolves its local link address.
::1/128
• Loopback address of local host.
• Equivalent to 127.0.0.1 in IPv4.
FE80::/10
• Link-local unicast address.
• Similar to the Windows autoconfiguration IP address of
169.254.x.x.
FF00::/8 • Multicast addresses.
All other addresses • Global unicast address.

Link-local Address
• Used for automatic address configuration, neighbor
discovery, router discovery, and by many routing
protocols.
• Dynamically created using a link-local prefix of
FE80::/10 and a 64-bit interface identifier.
• Link-local packets are unique only on the link, and
are not routable off the link.
128 bits
FE80
1111 1110 1000 0000 0000 0000 ... 0000 0000 0000
Interface ID
/10
FE80::/10
/64

IPv6 Global Unicast Address
1 128
ISP
/32
3
Customer Site
/48
16
End Site Subnet
/64
16 64
Device Address
128-bit
Interface ID
65
Network Prefix
64
RIR
/12
9 20
IANA
/3

IPv6 Global Unicast Address
• IPV6 Global Unicast Address
• 0010 2000::/3
• 0011 3000::/3
• All five RIRs are given a /12 from the /3 to further
distribute within the RIR region
• APNIC 2400:0000::/12
• ARIN 2600:0000::/12
• AfriNIC 2C00:0000::/12
• LACNIC 2800:0000::/12
• RIPE 2A00:0000::/12

IPv6 Multicast Address
• Multicasting is at the core of many IPv6 functions and it is a
replacement for the broadcast address.
• They are defined by the prefix FF00::/8.
• An interface may belong to any number of multicast groups.
• FF00:: to FF0F:: have the T flag = 0 means permanent and reserved.
F F
1111 1111
0 0
00XX XXXX
Group ID
Flags Scope
0 0 P T xxxx
8 bits
Flags:
• P = Prefix for unicast-based assignments
• T = 0 if permanent, 1 if temporary
/16/8
FF00::/8 Scope:
• 1 (0001) = Node
• 2 (0010) = Link
• 5 (0101) = Site
• 8 (1000) = Organization
• E (1110) = Global

Reserved IPv6 Multicast Address
Multicast Address Description
FF02::1 • All nodes on a link (link-local scope).
FF02::2 • All routers on a link.
FF02::9 • All routing information protocol (RIP) routers on a link.
FF02::1:FFxx:xxxx
• All solicited-node multicast addresses used for host
autoconfiguration and neighbor discovery (similar to ARP
in IPv4).
• The xx:xxxx is the far right 24 bits of the corresponding
unicast or anycast address of the node.
FF05::101 • All Network Time Protocol (NTP) servers.

Interface ID
• The lowest-order 64-bit field addresses may be
assigned in several different ways:
• Auto-configured from a 48-bit MAC address expanded
into a 64-bit EUI-64
• Assigned via DHCP
• Manually configured
• Auto-generated pseudo-random number
• Possibly other methods in the future

EUI-64
0 0 2 6 B 0 E 5 8 3 3 C
0 0 0 0 0 0 0
0 0 0 0 0 0 1 0
0 0 2 6 B 0 E 5 8 3 3 C
F F F E
0 2 2 6 B 0 E 5 8 3 3 CF F
Mac Address
EUI-64 Address
Interface Identifier
U/L bit
F E

IPv6 Autoconfiguration
Tentative address (link-local address)
Well-known link local prefix +Interface ID (EUI-64)
Ex: FE80::310:BAFF:FE64:1D
Is this
address
unique?
1. A new host is turned on.
2. Tentative address will be assigned to the new host.
3. Duplicate Address Detection (DAD) is performed. First the host transmit
a Neighbor Solicitation (NS) message to the solicited node multicast address
(FF02::1:FF64:001D) corresponding to its to be used address
5. If no Neighbor Advertisement (NA) message comes back then the address is unique.
6. FE80::310:BAFF:FE64:1D will be assigned to the new host.
Assign
FE80::310:BAFF:FE64:1D
2001:1234:1:1/64 network

IPv6 Autoconfiguration
FE80::310:BAFF:FE64:1D
Send me
Router
Advertisement
1. The new host will send Router Solicitation (RS) request to the all-routers multicast group
(FF02::2).
2. The router will reply Routing Advertisement (RA).
3. The new host will learn the network prefix. E.g, 2001:1234:1:1/64
4. The new host will assigned a new address Network prefix+Interface ID
E.g, 2001:1234:1:1:310:BAFF:FE64:1D
Router
Advertisement
Assign
2001:1234:1:1:310:BAFF:FE64:1D
2001:1234:1:1/64 network

Remember IPv4 Subnetting?
• 10.10.0.0/18
• What are the first and third /21 subnets?
• 192.168.1.0/24
• What are the second and fifth /28 subnets?

IPv6 Prefix

“Nibble” Boundaries
• A "nibble" is one hexadecimal digit (or 4 bits)
• You don't have to subnet based on nibbles. You can
use other prefixes, ex. /49, /51, /55 etc.
• But it is MUCH easier to identify addresses if you do

If /x is a multiple of 4

If /x is not a multiple of 4

“Easy” and “Complicated” Ranges
• 2001:db8:7::/48
• 2001:db8:7:xxxx:xxxx:xxxx:xxxx:xxxx
• 2001:db8:7:8000::/50
• 2001:db8:7:8xxx:xxxx:xxxx:xxxx:xxxx
• 2001:db8:7:9xxx:xxxx:xxxx:xxxx:xxxx
• 2001:db8:7:axxx:xxxx:xxxx:xxxx:xxxx
• 2001:db8:7:bxxx:xxxx:xxxx:xxxx:xxxx

IPv6 Subnettting
• Identify the first four /36 address blocks out of
2001:db8::/32
• Identify the first four /35 address blocks out of
2001:db8::/32

Not a single right way…
• If /32 is allocated, may be planned as:
• Infrastructure (/36)
• 1st /48
• Loopback: /64 (use as /128)
• Management: /64
• NOC: /56 (use as /64)
• Next /48
• Backbone P2P Peering: plan as /64 per subnet, use /127
• Next /48
• PE-CE Peering: plan as /64 per subnet, use /127
• Next /48
• Servers/Critical Infra
• Rest
• Client assignment: Minimum /48

Link-Local Address
• Start Wireshark on R1-VPCS1 link
• Turn on VPCS-1
• Check IPv6 Address on VPCS-1: show ipv6
Link-Local Address
autoconfigured using EUI-64
MAC Address to be used
to generate EUI-64
No Global Unicast
Address generated yet

IPv6 Configuration: R1
Enable IPv6 Routing:
R1#config terminal
R1(config)#ipv6 unicast-routing
Configure LAN Interfaces:
R1(config)#interface gi3/0
R1(config-if)#no shutdown
R1(config-if)#ipv6 address 2001:DB8:0:1::1/64
R1(config-if)#ipv6 enable
R1(config-if)#exit

Global Unicast Address
• Restart VPCS-1
• Check IPv6 Address on VPCS1
Global Unicast Address is
now autoconfigured

Wireshark Capture
Neighbor Solicitation
Neighbor Advertisement
Router Advertisement
Neighbor Advertisement

Configure P2P Interfaces:
R1(config-if)#ipv6 address 2001:DB8:0:12::/127
R1(config-if)#exit

R2#config terminal
R2(config-if)#exit

R2(config-if)#exit

R3#config terminal
R3(config-if)#exit

R3(config-if)#exit

Verification: R1
R1#show ipv6 interface brief
GigabitEthernet1/0 [up/up]
FE80::C801:33FF:FEB3:1C
2001:DB8:0:12::
FE80::C801:33FF:FEB3:38
2001:DB8:0:13::
FE80::C801:33FF:FEB3:54
2001:DB8:0:1::1
Link-Local Address
Global Unicast Address

Verification: R1
R1#show ipv6 interface gi1/0
GigabitEthernet1/0 is up, line protocol is up
IPv6 is enabled, link-local address is FE80::C801:33FF:FEB3:1C
No Virtual link-local address(es):
Global unicast address(es):
2001:DB8:0:12::, subnet is 2001:DB8:0:12::/127
Joined group address(es):
FF02::1
FF02::2
FF02::1:FF00:0
FF02::1:FFB3:1C
MTU is 1500 bytes
ICMP error messages limited to one every 100 milliseconds
ICMP redirects are enabled
ICMP unreachables are sent
ND DAD is enabled, number of DAD attempts: 1
ND reachable time is 30000 milliseconds (using 30000)
ND advertised reachable time is 0 (unspecified)
ND advertised retransmit interval is 0 (unspecified)
ND router advertisements are sent every 200 seconds
ND router advertisements live for 1800 seconds
ND advertised default router preference is Medium
Hosts use stateless autoconfig for addresses.
Multicast Groups this
link participates with

Verification: R1
R1#sh ipv6 route
IPv6 Routing Table - default - 7 entries
Codes: C - Connected, L - Local, S - Static, U - Per-user Static route
B - BGP, R - RIP, H - NHRP, I1 - ISIS L1
I2 - ISIS L2, IA - ISIS interarea, IS - ISIS summary, D - EIGRP
EX - EIGRP external, ND - ND Default, NDp - ND Prefix, DCE - Destination
NDr - Redirect, O - OSPF Intra, OI - OSPF Inter, OE1 - OSPF ext 1
OE2 - OSPF ext 2, ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2, l - LISP
C 2001:DB8:0:1::/64 [0/0]
via GigabitEthernet3/0, directly connected
L 2001:DB8:0:1::1/128 [0/0]
via GigabitEthernet3/0, receive
C 2001:DB8:0:12::/127 [0/0]
L 2001:DB8:0:12::/128 [0/0]
C 2001:DB8:0:13::/127 [0/0]
L 2001:DB8:0:13::/128 [0/0]
L FF00::/8 [0/0]
via Null0, receive
Only the local and connected
routes are available. No
routes from other routers

Verification
• Ping VPCS-2 from VPCS-1: Failed L
• Ping VPCS-3 from VPCS-1: Failed L

OSPF Configuration: R1
Configure Router-ID:
R1(config)#router ospfv3 1
R1(config-router)#router-id 1.1.1.1
R1(config-router)#exit
Enable OSPFv3 on the Interfaces:
R1(config-if)#ipv6 ospf 1 area 0
R1(config-if)#exit
R1(config-if)#exit
R1(config-if)#exit

R2(config-if)#exit
R2(config-if)#exit
R2(config-if)#exit

R3(config-if)#exit
R3(config-if)#exit
R3(config-if)#exit

Verification: R1
R1#show ipv6 route
C 2001:DB8:0:1::/64 [0/0]
L 2001:DB8:0:1::1/128 [0/0]
O 2001:DB8:0:2::/64 [110/2]
via FE80::C802:33FF:FEB4:1C, GigabitEthernet1/0
O 2001:DB8:0:3::/64 [110/2]
via FE80::C803:33FF:FEB5:38, GigabitEthernet2/0
C 2001:DB8:0:12::/127 [0/0]
L 2001:DB8:0:12::/128 [0/0]
C 2001:DB8:0:13::/127 [0/0]
L 2001:DB8:0:13::/128 [0/0]
O 2001:DB8:0:23::/127 [110/2]
L FF00::/8 [0/0]
via Null0, receive
All the routes (both local and
remote) are available now

Verification: R1
Codes: C - Connected, L - Local, S - Static, U - Per-user Static route
B - BGP, R - RIP, H - NHRP, I1 - ISIS L1
I2 - ISIS L2, IA - ISIS interarea, IS - ISIS summary, D - EIGRP
EX - EIGRP external, ND - ND Default, NDp - ND Prefix, DCE -
Destination
NDr - Redirect, O - OSPF Intra, OI - OSPF Inter, OE1 - OSPF ext 1
OE2 - OSPF ext 2, ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2, l
- LISP
O 2001:DB8:0:2::/64 [110/2]
O 2001:DB8:0:3::/64 [110/2]
O 2001:DB8:0:23::/127 [110/2]
Remote routes are
carried by OSPFv3

Verification
• Ping VPCS-2 from VPCS-1: Successful J
• Ping VPCS-3 from VPCS-1: Successful J

Questions?

IPv6 Addressing and Deployment Considerations

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