Implementing ADSL and Deploying Dial Access for IPv6

A Cisco router configured with IPv6 will advertise its IPv6 prefixes on one or more interfaces, allowing IPv6 clients to automatically configure their addresses. In IPv6, address assignment is performed at the network layer, in contrast to IPv4 where a number of functions are handled in the PPP layer. The only function handled in IPv6 control protocol is the negotiation of a unique interface identifier. Everything else, including Domain Name Server (DNS) server discovery, is done within the IPv6 protocol itself.

Contrary to IPv4 address assignment, an IPv6 user will be assigned a prefix, not a single address. Typically, the ISP assigns a 64- or 48-bit prefix.

In IPv6, ISPs assign long-lived prefixes to users, which has some impact on the routing system. In typical IPv4 environments, each network access server (NAS) has a pool of 24-bit addresses and users get addresses from this pool when dialing in. If a user dials another point of presence (POP) or is connected to another NAS at the same POP, a different IPv4 address is assigned.

Addresses for IPv6 are assigned using two methods:

• Stateless Address Autoconfiguration
• Prefix Delegation

Vendor-specific attributes (VSAs) are used to support AAA over IPv6. Cisco VSAs are inacl, outacl, prefix, and route.

You can configure prefix pools and pool names by using the AAA protocol. Customers can deploy an IPv6 RADIUS server or a TACACS+ server to communicate with Cisco devices.

• RADIUS over IPv6
• TACACS+ Over an IPv6 Transport
• IPv6 Prefix Pools

cisco-avpair = "ipv6:inacl#1=permit 2001:DB8:cc00:1::/48",
cisco-avpair = "ipv6:outacl#1=deny 2001:DB8::/10",

cisco-avpair = "ipv6:prefix#1=2001:DB8::/64",
cisco-avpair = "ipv6:prefix#2=2001:DB8::/64",

cisco-avpair = "ipv6:route#1=2001:DB8:cc00:1::/48",
cisco-avpair = "ipv6:route#2=2001:DB8:cc00:2::/48",

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    hostname name

4.    aaa new-model

5.    aaa authentication ppp {default | list-name} method1 [method2...]

6.    aaa authorization configuration default {radius | tacacs+

7.    show ipv6 route [ipv6-address | ipv6-prefix / prefix-length | protocol | interface-type interface-number

8.    virtual-profile virtual-template number

9.    interface serial controller-number : timeslot

10.    encapsulation encapsulation-type

11.    exit

12.    dialer-group group-number

13.    ppp authentication protocol1 [protocol2...] [if-needed] [list-name | default] [callin] [one-time] [optional]

14.    interface virtual-template number

15.    ipv6 enable

16.    dialer-list dialer-group protocol protocol-name {permit | deny | list access-list-number | access-group}

17.    radius-server host {hostname | ip-address} [test username user-name] [auth-port port-number] [ignore-auth-port] [acct-port port-number] [ignore-acct-port] [timeout seconds] [retransmit retries] [key string] [alias {hostname | ip-address}] [idle-time seconds

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. Enter your password if prompted.
Step 2	configure terminal Example: Router# configure terminal	Enters global configuration mode.
Step 3	hostname name Example: Router(config)# hostname cust1-53a	Specifies the hostname for the network server.
Step 4	aaa new-model Example: Router(config)# aaa new-model	Enables the AAA server.
Step 5	aaa authentication ppp {default | list-name} method1 [method2...] Example: Router(config)# aaa authentication ppp default if-needed group radius	Specifies one or more AAA authentication methods for use on serial interfaces that are running PPP.
Step 6	aaa authorization configuration default {radius | tacacs+ Example: Router(config)# aaa authorization configuration default radius	Downloads configuration information from the AAA server.
Step 7	show ipv6 route [ipv6-address | ipv6-prefix / prefix-length | protocol | interface-type interface-number Example: Router(config)# show ipv6 route	Shows the routes installed by the previous commands.
Step 8	virtual-profile virtual-template number Example: Router(config)# virtual-profile virtual-template 1	Enables virtual profiles by virtual interface template.
Step 9	interface serial controller-number : timeslot Example: Router(config)# interface serial 0:15	Specifies a serial interface created on a channelized E1 or channelized T1 controller (for ISDN PRI, channel-associated signaling, or robbed-bit signaling). This command also puts the router into interface configuration mode.
Step 10	encapsulation encapsulation-type Example: Router(config-if)# encapsulation ppp	Sets the encapsulation method used by the interface.
Step 11	exit Example: Router(config-if)# exit	Returns to global configuration mode.
Step 12	dialer-group group-number Example: Router(config)# dialer-group 1	Controls access by configuring an interface to belong to a specific dialing group.
Step 13	ppp authentication protocol1 [protocol2...] [if-needed] [list-name | default] [callin] [one-time] [optional] Example: Router(config)# ppp authentication chap	Enables Challenge Handshake Authentication Protocol (CHAP) or Password Authentication Protocol (PAP) or both and specifies the order in which CHAP and PAP authentication are selected on the interface.
Step 14	interface virtual-template number Example: Router(config)# interface virtual-template 1	Creates a virtual template interface that can be configured and applied dynamically in creating virtual access interfaces.
Step 15	ipv6 enable Example: Router(config)# ipv6 enable	Enables IPv6 processing on an interface that has not been configured with an explicit IPv6 address.
Step 16	dialer-list dialer-group protocol protocol-name {permit | deny | list access-list-number | access-group} Example: Router(config)# dialer-list 1 protocol ipv6 permit	Defines a dial-on-demand routing (DDR) dialer list for dialing by protocol or by a combination of a protocol and a previously defined access list.
Step 17	radius-server host {hostname | ip-address} [test username user-name] [auth-port port-number] [ignore-auth-port] [acct-port port-number] [ignore-acct-port] [timeout seconds] [retransmit retries] [key string] [alias {hostname | ip-address}] [idle-time seconds Example: Router(config)# radius-server host 172.17.250.8 auth-port 1812 acct-port 1813 key testing123	Specifies a RADIUS server host.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    hostname name

4.    interface bri number . subinterface-number [multipoint | point-to-point]

5.    encapsulation encapsulation-type

6.    ipv6 address autoconfig [default

7.    isdn switch-type switch-type

8.    ppp authentication {protocol1 [protocol2...]} [if-needed] [list-name | default] [callin] [one-time]

9.    ppp multilink [bap | required]

10.    exit

11.    dialer-list dialer-group protocol protocol-name {permit | deny | list access-list-number | access-group}

12.    ipv6 route ipv6-prefix / prefix-length {ipv6-address | interface-type interface-number ipv6-address]} [administrative-distance] [administrative-multicast-distance | unicast| multicast] [tag tag

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. Enter your password if prompted.
Step 2	configure terminal Example: Router# configure terminal	Enters global configuration mode.
Step 3	hostname name Example: Router(config)# hostname cust1-36a	Specifies the hostname for the network server.
Step 4	interface bri number . subinterface-number [multipoint | point-to-point] Example: Router(config)# interface bri 1.0	Configures a BRI interface.
Step 5	encapsulation encapsulation-type Example: Router(config-if)# encapsulation ppp	Sets the encapsulation method used by the interface.
Step 6	ipv6 address autoconfig [default Example: Router(config-if)# ipv6 address autoconfig	Indicates that the IPv6 address will be generated automatically.
Step 7	isdn switch-type switch-type Example: Router(config-if)# isdn switch-type basic-net3	Specifies the central office switch type on the ISDN interface.
Step 8	ppp authentication {protocol1 [protocol2...]} [if-needed] [list-name | default] [callin] [one-time] Example: Router(config-if)# ppp authentication chap	Enables Challenge Handshake Authentication Protocol (CHAP) or Password Authentication Protocol (PAP) or both and specifies the order in which CHAP and PAP authentication are selected on the interface.
Step 9	ppp multilink [bap | required] Example: Router(config-if)# ppp multilink	Enables Multilink PPP (MLP) on an interface and, optionally, enables Bandwidth Allocation Control Protocol (BACP) and Bandwidth Allocation Protocol (BAP) for dynamic bandwidth allocation.
Step 10	exit Example: Router(config-if)# exit	Exits interface configuration mode and returns to global configuration mode.
Step 11	dialer-list dialer-group protocol protocol-name {permit | deny | list access-list-number | access-group} Example: Router(config)# dialer-list 1 protocol ipv6 permit	Defines a dial-on-demand routing (DDR) dialer list for dialing by protocol or by a combination of a protocol and a previously defined access list.
Step 12	ipv6 route ipv6-prefix / prefix-length {ipv6-address | interface-type interface-number ipv6-address]} [administrative-distance] [administrative-multicast-distance | unicast| multicast] [tag tag Example: Router(config)# ipv6 route 2001:DB8::1/128 BRI1/0	Establishes static IPv6 routes. Use one command for each route.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    interface type number

4.    ipv6 nd prefix framed-ipv6-prefix

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. Enter your password if prompted.
Step 2	configure terminal Example: Router# configure terminal	Enters global configuration mode.
Step 3	interface type number Example: Router(config)# interface ethernet 0/0	Specifies an interface type and number, and places the router in interface configuration mode.
Step 4	ipv6 nd prefix framed-ipv6-prefix Example: Router(config-if)# ipv6 nd prefix framed-ipv6-prefix	Adds the prefix in a received RADIUS framed IPv6 prefix attribute to the interface's neighbor discovery prefix queue.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    ipv6 dhcp pool poolname

4.    prefix-delegation aaa [method-list method-list] [lifetime]

5.    sip address ipv6-address

6.    sip domain-name domain-name

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Router> enable	Enables privileged EXEC mode. Enter your password if prompted.
Step 2	configure terminal Example: Router# configure terminal	Enters global configuration mode.
Step 3	ipv6 dhcp pool poolname Example: Router(config)# ipv6 dhcp pool pool1	Configures a DHCP for IPv6 configuration information pool and enters DHCP for IPv6 pool configuration mode.
Step 4	prefix-delegation aaa [method-list method-list] [lifetime] Example: Router(config-dhcp)# prefix-delegation aaa method-list list1	Specifies that prefixes are to be acquired from AAA servers.
Step 5	sip address ipv6-address Example: Router(config-dhcp)# sip address 2001:DB8::2	Configures a SIP server IPv6 address to be returned in the SIP server's IPv6 address list option to clients.
Step 6	sip domain-name domain-name Example: Router(config-dhcp)# sip domain sip1.cisco.com	Configures a SIP server domain name to be returned in the SIP server's domain name list option to clients.

• Configuring the TACACS+ Server over IPv6
• Specifying the Source Address in TACACS+ Packets
• Configuring TACACS+ Server Group Options