Brocade Communications Systems Layer 3 Routing Configuration ICX 6650 - Manual (Page 421)

Brocade ICX 6650 Layer 3 Routing 403
53-1002603-01
IPv6 over IPv4 tunnels
The administrative distance is a value that the Layer 3 switch uses to compare this route with
routes from other route sources that have the same destination. (The Layer 3 switch performs this
comparison before placing a route in the IPv6 route table.) This parameter does not apply to routes
that are already in the IPv6 route table. In general, a low administrative distance indicates a
preferred route. By default, static routes take precedence over routes learned by routing protocols.
If you want a dynamic route to be chosen over a static route, you can configure the static route with
a higher administrative distance than the dynamic route.
IPv6 over IPv4 tunnels
NOTE
This feature is supported only with the IPv6 Layer 3 PROM and the full Layer 3 image.
To enable communication between isolated IPv6 domains using the IPv4 infrastructure, you can
manually configure IPv6 over IPv4 tunnels that provide static point-point connectivity.
As shown in Figure 29 , these tunnels encapsulate an IPv6 packet within an IPv4 packet.
FIGURE 29 IPv6 over an IPv4 tunnel
In general, a manually configured tunnel establishes a permanent link between switches in IPv6
domains. A manually configured tunnel has explicitly configured IPv4 addresses for the tunnel
source and destination.
This tunneling mechanism requires that the Layer 3 switch at each end of the tunnel run both IPv4
and IPv6 protocol stacks. The Layer 3 switches running both protocol stacks, or dual-stack routers,
can interoperate directly with both IPv4 and IPv6 end systems and routers. Refer to to the section
“Configuring IPv4 and IPv6 protocol stacks” in the Brocade ICX 6650 Administration Guide.
IPv6 over IPv4 tunnel configuration notes
• The local tunnel configuration must include both source and destination addresses.
• The remote side of the tunnel must have the opposite source/destination pair.
• A tunnel interface supports static and dynamic IPv6 configuration settings and routing
protocols.
• Duplicate Address Detection (DAD) is not currently supported with IPv6 tunnels. Make sure
tunnel endpoints do not have duplicate IP addresses.
• Neighbor Discovery (ND) is not supported with IPv6 tunnels.
• If a tunnel source port is a multi-homed IPv4 source, the tunnel will use the first IPv4 address
only. For proper tunnel operation, use the ip address option.
IPv4 Header IPv6 Header IPv6 Data IPv6 Header IPv6 Data IPv6 Header IPv6 Data
Dual-Stack L3 Switch
IPv6 Traffic Over IPv4 Tunnel
IPv6
Network
IPv6
Network
IPv4
Network
Dual-Stack L3 Switch IPv6 Host IPv6 Host