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Narbik , you really proved yr knowledge.> Date: Sat, 31 May 2008 11:31:29 -0700> From: narbikk@gmail.com> To: chris.gray@ozonenetworks.net> Subject: Re: IPV6 Tunnelling> CC: ccielab@groupstudy.com> > *There are 5 tunneling solution in IPv6:*> **> 1. *Using the ‘Tunnel mode ipv6ip’, in this case the tunnel source and> destination are configured with IPv4 addressing and the tunnel interface is> configured with IPv6. This will use protocol 41. This is used for IPv6/IPv4.> *> **> > R1(config)#int tunnel 1> > R1(config-if)#ipv6 address 12:1:12::1/64> > R1(config-if)#tunnel source 10.1.12.1> > R1(config-if)#tunnel destination 10.1.12.2> > R1(config-if)#*tunnel mode ipv6ip*> > 2. *Using the ‘Tunnel mode gre ipv6′, in this case the tunnel, tunnel source> and destination are all configured with IPv6 addressing. This is used for> IPv6/IPv6.*> > > BB1(config)#int tunnel 1> > BB1(config-if)#ipv6 address 121:1:121::111/64> > BB1(config-if)#tunnel source 10:1:111::111> > BB1(config-if)#tunnel destination 10:1:112::112> > BB1(config-if)#*tunnel mode gre ipv6*> > **> 3. *In this case, the tunnel mode is NOT used at all, note that the tunnel> interface is configured with IPv6 and the tunnel source and destination is> configured with IPv4 but no mention of tunnel mode. This configuration will> use protocol 47. This is used for IPv6/IPv4.*> > > R1(config)#int tunnel 13> > R1(config-if)#ipv6 address 13:1:13::1/64> > R1(config-if)#tunnel source 10.1.13.1> > R1(config-if)#tunnel destination 10.1.13.3> > 4. *Note in this case a special addressing is assigned to the tunnel> interface which is a concatenation of a reserved IPv6 address of 2002> followed by the translated IPv4 address of a given interface on the router.> In this configuration ONLY the tunnel source address is used and since the> tunnel is automatic, the destination address is NOT configured. The tunnel> mode is set to ‘Tunnel mode ipv6ip 6to4′. Note the IPv4 address of> 10.1.1.1is translated to 0A.01.01.01 and once concatenated, it will be> ‘2002:0A01:0101: or 2002:A01:101. This is used for IPv6/IPv4.*> > R1(config)#interface Tunnel14> > R1(config-if)#ipv6 address 2002:A01:101::/128> > R1(config-if)#tunnel source 10.1.1.1> > R1(config-if)#*tunnel mode ipv6ip 6to4*> > 5. *ISATAP, ISATAP works like 6to4 tunnels, with one major difference,> it uses a special IPv6 address which is formed as follows:*> > *In this tunnel mode, the network portion can be any IPv6 address, whereas> in 6to4 it had to start with 2002.*> > *Note when the IPv6 address is assigned to the tunnel interface, the> ‘eui-64′ is used, in this case the host portion of the IPv6 address starts> with ‘0000.5EFE’ and then the rest of the host portion is the translated> IPv4 address of the tunnel’s source IPv4 address. **This translation is> performed automatically unlike 6to4. This is used for IPv6/IPv4.> > *> > R4(config)#int tunnel 46> > R4(config-if)#ipv6 address 46:1:46::/64 eui-64> > R4(config-if)#tunnel source 10.44.44.44> > R4(config-if)#*tunnel mode ipv6ip ISATAP*> > > Sorry for the lengthy post and i hope this helped.> > On Sat, May 31, 2008 at 10:39 AM, Chris Gray > wrote:> > > I always use tunnel mode ipv6ip for these questions. Although, I don’t> > exactly know why! I didn’t think of using GRE and am slightly surprised it> > works. I was taught to use this method at a boot camp.> >> > Another area to research some more!> >> > Chris> >> >> >> > —–Original Message—–> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of> > Dennis Worth> > Sent: 31 May 2008 15:17> > To: CCIE3000> > Cc: Cisco certification> > Subject: Re: IPV6 Tunnelling> >> > I would add in dynamic with 6to4 tunnel to the mix. RFC 3056 should help> > along with :> >> >> > http://www.cisco.com/en/US/docs/ios/ipv6/configuration/guide/ip6-tunnel_ps64> > 41_TSD_Products_Configuration_Guide_Chapter.html#wp1037465> >> > HTH> >> > On Sat, May 31, 2008 at 6:14 AM, CCIE3000 wrote:> >> > > Just checking to see that I’ve got this straight in my head.> > >> > > When a question has wording along the lines of:> > >> > > Configure IPv6 tunnel over IPv4 network> > >> > > We should use tunnel mode gre ?> > >> > > From the follwoing debugs with tunnel mode ipv6ip I get the following:> > > l13: IPv6/IP encapsulated 150.1.3.3->150.1.1.1 (linktype=79, len=92)> > > *May 31 12:55:37.277: Tunnel13: IPv6/IP to classify> > > 150.1.1.1->150.1.3.3(len=92 ttl=253 tos=0xE0)> > > *May 31 12:55:37.277: Tunnel13: to decaps IPv6/IP packet 150.1.1.1->> > > 150.1.3.3 (len=92, ttl=253)> > > *May 31 12:55:37.277: Tunnel13: decapsulated IPv6/IP packet> > >> > > With tunnel mode gre I get the following:> > > *May 31 12:58:11.573: Tunnel13: GRE/IP encapsulated> > > 150.1.3.3->150.1.1.1(linktype=79, len=124)> > > *May 31 12:58:11.609: Tunnel13: GRE/IP to classify> > > 150.1.1.1->150.1.3.3(len=124 type=0×86DD ttl=253 tos=0×0)> > >> > > Also using debug ip packet detail I’m seeing protocol 47 with GRE and> > > protocol 41 when ipv6ip.> > >> > > Firstly, am I correct to use mode gre and secondly any tips on what to> > look> > > for in a question to decide the tunnel mode if it’s not stated?> > > Thanks,> > >> > >> > >