on - edited on by
ciscomoderator
I heard few customers complain that it's difficult to understand NAT64 document http://www.cisco.com/en/US/docs/ios/ios_xe/ipaddr/configuration/guide/iad_stateless_nat64_xe.html
, especially it's lack of a network diagram to show the corresponding interface and whereabouts of the IPv4 and IPv6 address.
This posting is intended to provide a working example along with detail illustration of network diagram.
Network Diagram
Click the image to enlarge
The goal is for IPv4 router R1 to communicate with IPv6 subnet host by R2's F0/1 interface. Since R1 is IPv4 only device, it does not understand IPv6 address, it need an IPv4 address to communicate to. In this case, the IPv4 subnet we choose is 192.1.1.0/24. And nat64 prefix define the stateless NAT64 prefix to be added to the IPv4 hosts to translate the IPv4 address into an IPv6 address. Please refer to this link for Ipv4-Translatable IPv6 address format. http://www.cisco.com/en/US/docs/ios/ios_xe/ipaddr/configuration/guide/iad_stateless_nat64_xe.html#wp1070936
Address Translation Between IPv4 and IPv6:
Destination Translation:
Upon receiving IPv4 packet destination to 192.1.1.1, NAT64 translate the destination IPv4 address into IPv6 address 2001:DB9:0:1::C001:101. Here, C0010101 is the hexadecimal format of 192.1.1.1. 2001:DB9:0:1::/96 is the pre-defined nat64 prefix from "neat64 prefix stateless" command.
Source Translation:
NAT64 also translate source IPv4 address 192.168.5.2 into IPv6 address 2001:DB9:0:1::C0A8:502. Again, C0A80502 is hexadecimal format of 192.168.5.2.
IPv6 to IPv4 Translation:
Upon receiving return IPv6 Traffic, NAT64 translate source IPv6 address 2001:DB9:0:1::C001:101 back into IPv4 192.1.1.1 and destination IPv6 address 2001:DB9:0:1::C0A8:501 back into IPv4 address 192.168.5.2.
Connectivity Test:
R1#ping 192.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/2 ms
R2#debug ipv6 icmp
ICMP packet debugging is on
R2#
*Feb 17 22:25:49.842: ICMPv6: Received echo request from 2001:DB9:0:1::C0A8:502
*Feb 17 22:25:49.842: ICMPv6: Sending echo reply to 2001:DB9:0:1::C0A8:502
*Feb 17 22:25:49.842: ICMPv6: Received echo request from 2001:DB9:0:1::C0A8:502
*Feb 17 22:25:49.842: ICMPv6: Sending echo reply to 2001:DB9:0:1::C0A8:502
*Feb 17 22:25:49.842: ICMPv6: Received echo request from 2001:DB9:0:1::C0A8:502
*Feb 17 22:25:49.846: ICMPv6: Sending echo reply to 2001:DB9:0:1::C0A8:502
Other Relevant Output:
ASR1k#sh ipv6 route
IPv6 Routing Table - default - 5 entries
Codes: C - Connected, L - Local, S - Static, U - Per-user Static route
B - BGP, R - RIP, I1 - ISIS L1, I2 - ISIS L2
IA - ISIS interarea, IS - ISIS summary, D - EIGRP, EX - EIGRP external
ND - Neighbor Discovery
O - OSPF Intra, OI - OSPF Inter, OE1 - OSPF ext 1, OE2 - OSPF ext 2
ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2
C 2001:FF::/96 [0/0]
via GigabitEthernet0/0/1, directly connected
L 2001:FF::1/128 [0/0]
via GigabitEthernet0/0/1, receive
S 2001:DB9:0:1::/96 [1/0]
via ::42, NVI0
O 2001:DB9:0:1::C001:100/120 [110/2]
via FE80::20F:35FF:FE2C:9AD9, GigabitEthernet0/0/1
L FF00::/8 [0/0]
via Null0, receive
R2#sh ipv6 route
IPv6 Routing Table - 7 entries
Codes: C - Connected, L - Local, S - Static, R - RIP, B - BGP
U - Per-user Static route
I1 - ISIS L1, I2 - ISIS L2, IA - ISIS interarea, IS - ISIS summary
O - OSPF intra, OI - OSPF inter, OE1 - OSPF ext 1, OE2 - OSPF ext 2
ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2
C 2001:FF::/96 [0/0]
via ::, FastEthernet0/0
L 2001:FF::2/128 [0/0]
via ::, FastEthernet0/0
C 2001:DB9:0:1::C001:100/120 [0/0]
via ::, FastEthernet0/1
L 2001:DB9:0:1::C001:101/128 [0/0]
via ::, FastEthernet0/1
S 2001:DB9:0:1::C0A8:502/128 [1/0]
via 2001:FF::1
L FE80::/10 [0/0]
via ::, Null0
L FF00::/8 [0/0]
via ::, Null0
