This topic is to discuss the following lesson:
I not understand very well why the eui-64 i s needed, and also why on R1 the command
tunnel mode ipv6ip isatap
is not needed.
Also I’m testing this configuration on gns3 and router r1 not install a static route.
According to Cisco documentation, when configuring ISATAP:
The IPv6 tunnel interface must be configured with a modified EUI-64 address
because the last 32 bits in the interface identifier are constructed using the IPv4 tunnel source address.
If you were to specify the address fully, the ISATAP operation would not function.
Also, when you configure
tunnel mode ipv6ip isatap on the headend, there is no need to specify the mode in which the tunnel will be functioning on the client. On the client, you also set
ipv6 address autoconfig, which means that it will obtain the IPv6 address (and the mode of the tunnel) from the headend.
I hope this has been helpful!
Hi Rene and Laz,
Would you say that the ISATAP operation is very similar to the DMVPN Phase 1 where all of the tunnel traffic has to traverse the “Headend” router just like with DMVPN phase 1 and its “HUB”?
It is similar only so far as the traffic actually traverses the router itself (either the head end or the HUB in each case) to get to its destination. However, beyond that, the purpose and the mechanisms of the two features you mention are completely different.
I hope this has been helpful!
In the ISATAP lesson, client config section, the tunnel mode command says:
tunnel mode ipv6ip and there is no
isatap in the end. Was that left out on purpose -because it’s a client- or is that a typo?
That’s right, the client only needs
tunnel mode ipv6ip . No need to add the
isatap keyword there.
I tried to lab this up in CML2 but couldn’t get it working. The configs are identical apart form the interfaces being Gigabit and command no ipv6 nd ra suppress being slightly different.
interface Tunnel0 no ip address no ip redirects ipv6 address 2001:DB8:13:13::/64 eui-64 no ipv6 nd ra suppress tunnel source GigabitEthernet0/0 tunnel mode ipv6ip isatap
interface Tunnel0 no ip address ipv6 address autoconfig tunnel source GigabitEthernet0/0 tunnel mode ipv6ip tunnel destination 192.168.23.3
The client is not acquiring an ipv6 address.
Tunnel0 is up, line protocol is up IPv6 is enabled, link-local address is FE80::C0A8:C01 No Virtual link-local address(es): Stateless address autoconfig enabled No global unicast address is configured Joined group address(es): FF02::1 FF02::1:FFA8:C01 MTU is 1480 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 NS retransmit interval is 1000 milliseconds
R1#sh ipv6 int brief GigabitEthernet0/0 [up/up] unassigned Tunnel0 [up/up] FE80::C0A8:C01
The headend (R3) sh ipv6 int tunnel 0 output is as follows:
Tunnel0 is up, line protocol is up IPv6 is enabled, link-local address is FE80::5EFE:C0A8:1703 No Virtual link-local address(es): Global unicast address(es): 2001:DB8:13:13:0:5EFE:C0A8:1703, subnet is 2001:DB8:13:13::/64 [EUI] Joined group address(es): FF02::1 FF02::1:FFA8:1703 MTU is 1480 bytes ICMP error messages limited to one every 100 milliseconds ICMP redirects are enabled ICMP unreachables are sent ND DAD is not supported ND reachable time is 30000 milliseconds (using 30000) ND NS retransmit interval is 1000 milliseconds
which differs slightly from output in the course notes.
I have confirmed full connectivity via OSPF.
I’m beginning to think this is CML related.
Thanks for any help.