
Generic Routing Encapsulation Tunnel
303528-A Rev 00
13-3
Figure 13-1. GRE Tunneling
Avoiding Tunnel Misconfiguration
Before configuring a tunnel, you should be aware of a limitation inherent in the
use of all tunnels, including GRE tunnels. A tunnel is a virtual point-to-point
connection between two routers that are actually several hops apart. This point-to-
point connection can hide the real distance between the routers from portions of
the network leading to unintended, suboptimal routing decisions, and, in some
cases, to routing loops.
Router 2
Router 1
Router
interface
Router
interface
Tunnel
interface
Tunnel
interface
Host
1
Host
2
Key
IP0064A
Internet/Intranet
10.0.0.1
8.0.0.2
data
data
MAC header
Source IP address
Destination IP address
11.0.0.10
11.0.0.20
10.0.0.1
8.0.0.2
MAC header
Source IP address
Destination IP address
GRE header
Source IP address
Destination address
10.0.0.1
8.0.0.2
data
MAC header
Source IP address
Destination IP address
Transport protocol
Passenger protocol
Comentários a estes Manuais