Regional Cisco Networking
Academy Conference 2014
Giving you the knowledge and
confidence to teach IPv6
DHCPv6-PD (Prefix Delegation)
IPv6 Address Allocation to the Home
Rick Graziani
CS/CIS Instructor
Cabrillo College
Cisco Networking Academy, U.S./Canada
© 2013 Cisco Systems, Inc. All rights reserved. Cisco confidential.
1
The World of IPv4 – DHCPv4 and NAT
NAT
ISP
G0/1
G0/1
DHCPv4
Public IPv4 Address
for the interface
HOME
DHCPv4
G0/0
Private IPv4 Address
10.0.0.0/8
172.16.0.0/12
192.168.0.0/16
• ISP only has to deliver a public IPv4 address for Home router interface.
• DHCPv4 and RFC 1918 private address space is used for home network.
• NAT is used for translation – but has its drawbacks!
• No NAT (like that… kind of) for IPv6
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2
The World of IPv6 – DHCPv6-PD (Prefix Delegation)
Complete IPv6 Reachability
Delegating
Router (DR)
ISP-DR
Requesting
Router (RR)
G0/1
G0/1
HOME-RR G0/0
Global IPv6 Address
Global IPv6 Address
• IPv6 End-to-end reachability:
• Home network gets its own IPv6 prefix (public address)
• No NAT
• ISP router is known as the Delegating Router (DR)
• HOME router is known as the Requesting Router (RR)
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3
The World of IPv6 – DHCPv6-PD (Prefix Delegation)
Complete IPv6 Reachability
Delegating
Router (DR)
ISP-DR
G0/1
Requesting
Router (RR)
G0/1
HOME-RR G0/0
Global IPv6 Address
Global IPv6 Address
After getting an IPv6 address on its ISP-facing interface, HOME-RR needs to:
Step 1: Request a Prefix for its LAN(s)
Step 2: Subnet the prefix for its LANs (optional) – Get a /48 but assign /64s
Step 3: Assign an IPv6 address from the prefix to its LAN interface
Step 4: Advertises the prefix in a Router Advertisement to devices on the LAN
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4
The World of IPv6 – DHCPv6-PD (Prefix Delegation)
Complete IPv6 Reachability
Delegating
Router (DR)
ISP-DR
Requesting
Router (RR)
G0/1
G0/1
HOME-RR
IPv6 Address for the interface:
• SLAAC
• DHCPv6 (Stateful or Stateless)
G0/0
?
• First, HOME’s ISP facing interface needs an IPv6 address.
• Similar to any IPv6 client it may dynamically get an address using:
• SLAAC - Using prefix in RA
• Stateless DHCPv6 – Using prefix in RA and perhaps DNS address from DHCPv6 server
• Stateful DHCPv6 - Like DHCPv4
• What about the address for the HOME LAN?
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5
The World of IPv6 – DHCPv6-PD (Prefix Delegation)
Delegating
Router (DR)
ISP-DR
3
Requesting
Router (RR)
G0/1
G0/1
DHCPv6-PD REQUEST
RA with /64 prefix
HOME-RR G0/0 3
1
G0/1
2
DHCPv6-PD REPLY with /48 prefix
Step 1. HOME asks the ISP for an address to allocate for it’s LANs
• DHCPv6-PD is initiated by the RR!
Step 2. ISP delegates an IPv6 prefix for HOME
• Example: ISP sends HOME a /48 prefix
Step 3. HOME advertises prefix using SLAAC RA messages (currently only option)
• HOME advertises the prefix out its interfaces using ICMPv6 Router Advertisement messages
• HOME assigns the prefix or subnets of the prefix to one or more interfaces
© 2013 Cisco Systems,
Inc. All rights reserved.
• Example: HOME interfaces are assigned
/64 subnets
from Cisco
theconfidential.
/48 prefix
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Our Example - DHCPv6-PD
2001:DB8:FEED:6::/64
ISP-DR
G0/1
:1
SLAAC
2001:DB8:AB00:1::/64
G0/0
G0/1
:EUI-64 HOME-RR :1
Router Advertisement
2001:DB8:FEED:6::/64
SLAAC
DHCPv6
Prefix Delegation
Prefix Delegation for the HOME
2001:DB8:AB00:/48
Router Advertisement
2001:DB8:AB00:1::/64
• ISP will deliver an IPv6 address for HOME’s G0/1 interface using SLAAC
• ISP will delegate the 2001:DB8:AB00::/48 prefix to HOME to allocate to its LANs
• HOME will use the 2001:DB8:AB00:1::/64 subnet for its G0/0 interface.
• Assign :1 to the G0/0 interface
• G0/0 LAN will receive the 2001:DB8:AB00:1::/64 prefix and other information using SLAAC (RA).
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7
RA and DHCPv6-PD Messages Note: If instead of SLAAC, HOME uses
SLAAC
ICMPv6 Router Solicitation
ICMPv6 Router Advertisement
ISP
DR
G0/1
G0/1
SOLICIT: Prefix Delegation request
DHCPv6-PD
ADVERTISE
REQUEST
DHCPv6 for its G0/1 address, a separate set
of DHCPv6 messages will be exchanged
between the two routers.
HOME
RR
G0/0
The RR must be enabled with the PD option
In the case where the RR only has one DR
the rapid commit option omits these two
steps.
REPLY: Include Prefix
ICMPv6 Router Advertisement (RA)
SLAAC
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8
HOME-RR Configuration
2001:DB8:FEED:6::/64
ISP-DR
G0/1
:1
2
2001:DB8:FEED:6::/48
2001:DB8:AB00:1::/64
G0/1
G0/0
:EUI-64 HOME-RR :1
1
Router Solicitation
Router Advertisement
DHCPv6 PD Request
3
HOME-RR(config)# ipv6 unicast-routing
HOME-RR(config)# interface gig 0/1
HOME-RR(config-if)# ipv6 address autoconfig default
HOME-RR(config-if)# ipv6 dhcp client pd DHCPV6-PREFIX-FROM-ISP
! Required to send RA
!
!
!
!
Use RA & add default
Request DHCPv6-PD.
rapid-commit option
can be used.
HOME-RR(config)# interface gig 0/0
HOME-RR(config-if)# ipv6 address DHCPV6-PREFIX-FROM-ISP 0:0:0:1::1/64
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! RA /48 from PD
9
HOME-RR Configuration
2001:DB8:FEED:6::/64
ISP-DR
G0/1
:1
2001:DB8:AB00:1::/64
G0/1
G0/0
:EUI-64 HOME-RR :1
3
DHCPv6 PD Request
2001:DB8:AB00::/48
DHCPv6 PD Reply
1
2001:DB8:AB00:1::1/64
2001:DB8:AB00:1::/64
Router Advertisement
2
3
HOME-RR(config)# interface gig 0/1
HOME-RR(config-if)# ipv6 address autoconfig default
HOME-RR(config-if)# ipv6 dhcp client pd DHCPV6-PREFIX-FROM-ISP
HOME-RR(config)# interface gig 0/0
HOME-RR(config-if)# ipv6 address DHCPV6-PREFIX-FROM-ISP 0:0:0:1::1/64
First 48 bits replaced by the prefix received by DHCPv6-PD
Subnet-ID
2001:DB8:AB00::
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! For G0/0 & RA
Interface ID
10
ISP-DR Configuration
2001:DB8:FEED:6::/64
ISP-DR
SLAAC
DHCPv6-PD
G0/1
:1
Router Advertisement
2001:DB8:FEED:6::/64
2001:DB8:AB00:1::/64
G0/1
G0/0
:EUI-64 HOME-RR :1
For G0/1 interface
Prefix Delegation for the HOME
2001:DB8:AB00:/64
For HOME LANs
ISP-DR(config)# ipv6 unicast-routing
ISP-DR(config)# interface gig 0/1
ISP-DR(config-if)# ipv6 address 2001:db8:feed:6::1/64
ISP-DR(config-if)# ipv6 address fe80::feed:1 link-local
ISP-DR(config-if)# ipv6 dhcp server DHCPV6-CLIENT-ADDRESS
ISP-DR(config)# ipv6 dhcp pool DHCPV6-CLIENT-ADDRESS
ISP-DR(config-dhcpv6)# prefix-delegation pool DHCPV6-PD-POOL
ISP-DR(config-dhcpv6)# dns-server 2001:DB8:AAAA::1
! Also a DHCPv6 server
Pool can include address
prefix command if stateful
DHCPv6 is used instead of
SLAAC.
ISP-DR(config)#
ipv6 local pool ©DHCPV6-PD-POOL
2001:DB8:AB00::/40 48
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11
ISP-DR Configuration
2001:DB8:FEED:6::/64
ISP-DR
G0/1
:1
2001:DB8:AB00:1::/64
G0/1
G0/0
:EUI-64 HOME-RR :1
2001:DB8:AB00::/40
2001:DB8:AB00::/48
2001:DB8:AB01::/48
2001:DB8:AB02::/48
…
2001:DB8:ABFF::/48
DHCPv6 PD Reply
2001:DB8:AB00:1::/64
Router Advertisement
ipv6 address DHCPV6-PREFIX-FROM-ISP 0:0:0:1::1/64
ISP-DR(config)# ipv6 dhcp pool DHCPV6-CLIENT-ADDRESS
ISP-DR(config-dhcpv6)# prefix-delegation pool DHCPV6-PD-POOL ! DHCPv6 address pool
ISP-DR(config-dhcpv6)# dns-server 2001:DB8:AAAA::1
! DNS address for DHCPv6-PD
ISP-DR(config)# ipv6 local pool DHCPV6-PD-POOL 2001:DB8:AB00::/40 48
! PD pool
Reserve a /40 to allocate addresses for ISP’s DHCPv6-PD clients
2001:DB8:ABxx::/40
From the /40 each DHCPv6-PD client will get a /48
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12
Verifying DHCPv6-PD
2001:DB8:FEED:6::/64
ISP-DR
G0/1
:1
SLAAC
2001:DB8:AB00:1::/64
G0/0
G0/1
:EUI-64 HOME-RR :1
Router Advertisement
2001:DB8:FEED:6::/64
SLAAC
DHCPv6
Prefix Delegation
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Prefix Delegation for the HOME
2001:DB8:AB00:/48
Router Advertisement
2001:DB8:AB00:1::/64
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13
ISP-DR Verification
2001:DB8:FEED:6::/64
ISP-DR
G0/1
:1
2001:DB8:AB00:1::/64
G0/1
G0/0
:EUI-64 HOME-RR :1
ISP-DR# show ipv6 dhcp interface gig 0/1
GigabitEthernet0/1 is in server mode
Using pool: DHCPV6-CLIENT-ADDRESS
Preference value: 0
Hint from client: ignored
ISP-DR(config)# interface gig 0/1
Rapid-Commit: disabled
ISP-DR(config-if)# ipv6 dhcp server
ISP-DR#
rapid-commit option not included
DHCPV6-CLIENT-ADDRESS
ISP-DR(config)# ipv6 dhcp pool DHCPV6-CLIENT-ADDRESS
ISP-DR(config-dhcpv6)# prefix-delegation pool DHCPV6-PD-POOL
ISP-DR(config-dhcpv6)# dns-server 2001:DB8:AAAA::1
ISP-DR(config)# ipv6 local pool DHCPV6-PD-POOL 2001:DB8:AB00::/40 48
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14
ISP-DR Verification
2001:DB8:FEED:6::/64
ISP-DR
G0/1
:1
2001:DB8:AB00:1::/64
G0/1
G0/0
:EUI-64 HOME-RR :1
ISP-DR# show ipv6 local pool DHCPV6-PD-POOL
Prefix is 2001:DB8:AB00::/40 assign /48 prefix
1 entries in use, 255 available, 0 rejected
0 entries cached, 1000 maximum
User
Prefix
Interface
00030001885A923B29E000040001
2001:DB8:AB00::/48
ISP-DR#
ISP-DR(config)# interface
gig 0/1
ISP-DR(config-if)# ipv6 dhcp server DHCPV6-CLIENT-ADDRESS
Other verification commands:
• show ipv6 dhcp binding
• show ipv6 dhcp interface
ISP-DR(config)# ipv6 dhcp pool DHCPV6-CLIENT-ADDRESS
ISP-DR(config-dhcpv6)# prefix-delegation pool DHCPV6-PD-POOL
ISP-DR(config-dhcpv6)# dns-server 2001:DB8:AAAA::1
ISP-DR(config)# ipv6 local pool DHCPV6-PD-POOL 2001:DB8:AB00::/40 48
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15
HOME-RR Verification
2001:DB8:FEED:6::/64
ISP-DR
G0/1
:1
2001:DB8:AB00:1::/64
G0/1
G0/0
:EUI-64 HOME-RR :1
HOME-RR# show ipv6 inter brief
GigabitEthernet0/0
[up/up]
FE80::1
2001:DB8:AB00:1::1
GigabitEthernet0/1
[up/up]
FE80::8A5A:92FF:FE3B:29E1
2001:DB8:FEED:6:8A5A:92FF:FE3B:29E1
HOME-RR#
SLAAC
HOME-RR(config)# ipv6 unicast-routing
HOME-RR(config)# interface gig 0/1
HOME-RR(config-if)# ipv6 address autoconfig default
HOME-RR(config-if)# ipv6 dhcp client pd DHCPV6-PREFIX-FROM-ISP
HOME-RR(config)# interface gig 0/0
HOME-RR(config-if)# ipv6 address DHCPV6-PREFIX-FROM-ISP 0:0:0:1::1/64
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16
HOME-RR Verification
2001:DB8:FEED:6::/64
ISP-DR
G0/1
:1
2001:DB8:AB00:1::/64
G0/1
G0/0
:EUI-64 HOME-RR :1
Router Advertisement
HOME-RR# show ipv6 interface gig 0/0
2001:DB8:AB00:1::/64
GigabitEthernet0/0 is up, line protocol is up
General-prefix in use for addressing
Global unicast address(es):
2001:DB8:AB00:1::1, subnet is 2001:DB8:AB00:1::/64 [CAL/PRE]
<Output ommited>
Hosts use stateless autoconfig for addresses.
HOME-RR#
HOME-RR(config)# ipv6 unicast-routing
HOME-RR(config)# interface gig 0/1
HOME-RR(config-if)# ipv6 address autoconfig default
HOME-RR(config-if)# ipv6 dhcp client pd DHCPV6-PREFIX-FROM-ISP
HOME-RR(config)# interface gig 0/0
HOME-RR(config-if)# ipv6 address DHCPV6-PREFIX-FROM-ISP 0:0:0:1::1/64
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17
HOME-RR Verification
2001:DB8:FEED:6::/64
ISP-DR
G0/1
:1
Default Route
2001:DB8:AB00:1::/64
G0/1
G0/0
:EUI-64 HOME-RR :1
X2001:DB8:AB00::/48
HOME-RR# show ipv6 route
IPv6 Routing Table - default - 7 entries
Codes: ND - ND Default, NDp - ND Prefix, DCE - Destination, NDr – Redirect
ND
::/0 [2/0]
via FE80::FEED:1, GigabitEthernet0/1
S
2001:DB8:AB00::/48 [1/0]
via Null0, directly connected Discard route
<Output omitted>
HOME-RR#
HOME-RR(config)# ipv6 unicast-routing
HOME-RR(config)# interface gig 0/1
HOME-RR(config-if)# ipv6 address autoconfig default
HOME-RR(config-if)# ipv6 dhcp client pd DHCPV6-PREFIX-FROM-ISP
HOME-RR(config)# interface gig 0/0
HOME-RR(config-if)# ipv6 address DHCPV6-PREFIX-FROM-ISP 0:0:0:1::1/64
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19
HOME-RR Verification
2001:DB8:FEED:6::/64
ISP-DR
G0/1
:1
2001:DB8:AB00:1::/64
G0/1
G0/0
:EUI-64 HOME-RR :1
Router Advertisement
2001:DB8:AB00:1::/64
PC> ipconfig
HOME-RR(config)# interface gig 0/0
HOME-RR(config-if)# ipv6 address DHCPV6-PREFIX-FROM-ISP 0:0:0:1::1/64
HOME-RR(config-if)# ipv6 address fe80::1 link-local
For a recognizable default gateway address
Windows IP Configuration
Ethernet adapter Local Area Connection:
IPv6 Address . . . . . . . . . . 2001:db8:ab00:1:1005:b37e:7e61:7ceb
Link-local IPv6 Address. . . . . fe80::1005:b37e:7e61:7ceb
Default Gateway. . . . . . . . . fe80::1
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SLAAC
Router(config)# ipv6 unicast-routing
Router(config-if)# no ipv6 nd suppress-ra
! This is the default
Stateless DHCPv6
Router(config-if)# ipv6 nd other-config-flag
Router(config-if)# ipv6 dhcp server POOL-NAME
Client
Server
Router
Advertisement
Router
Advertisement
M=1
O=1
Router(config)# ipv6 dhcp pool POOL-NAME
Router(config-dhcpv6)# dns-server dns-address
Router(config-dhcpv6)# domain-name domain-name
Stateful DHCPv6
Router(config-if)# ipv6 nd managed-config-flag
Router(config-if)# ipv6 dhcp server POOL-NAME
To all DHCPv6 Servers
Router(config)# ipv6 dhcp pool POOL-NAME
Router(config-dhcpv6)# address prefix ipv6-prefix/prefix-length
Router(config-dhcpv6)# dns-server dns-address
Router(config-dhcpv6)# domain-name domain-name
DHCPv6-PD option
Router(config-dhcpv6)# prefix-delegation pool ipv6-prefix/prefix-length
! Add to POOL-NAME
Router(config)# ipv6 local pool POOL-NAME ipv6-address-block/prefix-length subnet-prefix-length
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21
Server
Client
Router as SLAAC client
SLAAC
Client(config-if)# ipv6 address autoconfig [default] ! default option used for DHCPv6-PD
Router as a DHCPv6 Client (Stateless or Stateful)
DHCPv6
Client(config-if)# ipv6 enable
! IPv6 link-local required to send DHCPv6 messages
Client(config-if)# ipv6 address dhcp
Router as a DHCPv6-PD Client
DR-facing Interface using SLAAC or DHCPv6
Client(config-if)# ipv6 dhcp client pd POOL-NAME
! Request DHCPv6-PD
LAN-facing Interface
Client(config)# ipv6 address POOL-NAME ::subnet-interfaceid-address/prefix-length
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22
• DHCPv4 – Remember IPv4?
• ICMPv6 – Used more than ICMPv4
• SLAACers – IPv6 Addressing without DHCPv6
• Stateless DHCPv6 – I have my address but need some other stuff
• Stateful DHCPv6 – Just like DHCPv4 (only different)
• DHCPv6-PD (Prefix Delegation) – IPv6 Prefix for the “home”
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23
Shameless plug!
• Rick Graziani - [email protected]
• PowerPoints for CCNA, CCNP, IPv6
• www.cabrillo.edu/~rgraziani
• Username = cisco
• Password = perlman
Quality time
with my two
nieces…
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24
Rick Graziani - [email protected]
www.cabrillo.edu/~rgraziani
Username = cisco
Password = perlman
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