Ip Encapsulation Within Ip; Tunneling Operation - Alcatel-Lucent OmniSwitch 6850-48 Network Configuration Manual

Tunneling

IP Encapsulation within IP

IPIP tunneling is a method by which an IP packet is encapsulated within another IP packet. The Source
Address and Destination Address of the outer IP header identifies the endpoints of tunnel. Whereas Source
Address and Destination Address of the inner IP header identifies the original sender and recipient of the
packet, respectively.
Consider the following when configuring the IPIP tunnel interfaces:
•
A switch can support up to 127 IPIP tunnel interfaces.
•
IPIP tunnel interfaces are included in the maximum number of IP interfaces that are supported on the
switch.

Tunneling operation

The diagram below illustrates how packets are forwarded over the tunnel.
Private IP Network
IP Host
50.0.0.1
Switch A
IP Host
In the above diagram, IP packets flowing from the private IP network 50.0.0.0 to the private IP network
40.0.0.0 are encapsulated by the tunneling protocol at switch A and forwarded to switch B. Intermediate
switches route the packets using addresses in the delivery protocol header. Switch B extracts the original
payload and routes it to the appropriate destination in the 40.0.0.0 network.
The tunnel interface is identified as being up when all of the following are satisfied:
•
Both source and destination addresses are assigned.
•
The source address of the tunnel is one of the switch's IP interface addresses that is either a VLAN or
Loopback0 interface.
page 24-34
50.0.0.0
24.24.24.1
Tunnel Endpoint
23.23.23.1
Outer IP Header : 23.23.23.1, 155.2.2.2
Inner IP Header : 50.0.0.1, 40.0.0.1
OmniSwitch AOS Release 6 Network Configuration Guide
Private IP Network
40.0.0.0
Switch B
24.24.24.2
Tunnel Endpoint
155.2.2.2
Configuring IP
IP Host
IP Host
40.0.0.1
September 2009