IPv6 Tunnels

• point-to-point tunnels
• MCT ( manually configured tunnel )
• GRE ( Generic Routing Encapsulation )

• Virtual point-to-point between two IPv4 routers
• IPv6 iGP routing protocols can run over these virtual links.

MCT

Show interface tunnel
show ipv6 interface brief

• Create a loopback interface
• assign an IPv4 adress
• create an ‘interface tunnel’ with logical number
  • tunnel source 10.10.10.10
  • tunnel mode ipv6ip
  • add IPv6 adress to the tunnel

GRE

• difference is tunnel mode
  • If you don’t configure a tunnel mode command it falls back to GRE
  • tunnel mode gre ip

6to4 tunnels

• 6to4 tunnels do no support IPv6 iGP.
• 6to4 tunnels are multipoint

ISATAP

• Intra-Site Automatic Tunnel Addressing Protocol
• ISATAP is designed for transporting IPv6 packets within a site
• Can use any unicast IPv6 prefix (/64) and the IPv4 adress is encoded in the last 32bits of the IPv6 address
  • First 32bits contain the value 0000:5RER to indicate it’s an ISATAP adress.
  • Last 32bits contain the IPv4 adress.
  • FE80::000:5efe::32bitIPv4Addr