Motorola Series Switch WS5100 - Manual (Page 212)

5-42 WS5100 Series Switch System Reference Guide
• Assigning priority to different types of traffic
• Assigning security levels to different types of traffic
The advantages of using Tunnel include:
1. It provides communication between sub-network that have invalid or non-contiguous network addresses.
2. Multiple protocols types can be consolidated on a common backbone for reduced operational cost.
3. Assurance of privacy and security in shared networks that support multiple enterprise customers.
GRE is a multi protocol carrier and it encapsulates IP and other packets inside IP tunnel. In a GRE tunnel, a
router at each side of the tunnel encapsulates protocol-specific packets in an IP header and creates a virtual
point-to-point link to the routers at the other end of an IPcloud, where the IP header is stripped off. By
connecting multi-protocol sub-networks in a single-protocol backbone environment, IP tunneling allows
network expansion across a single-protocol backbone environment.
GRE allows a newly created tunnel to pass traffic to the other end of the tunnel. This enables the network
administrator access to traffic mapped to the GRE tunnel. The switch provides a path to tunnel all WLAN
traffic to the other end of the tunnel. This enables network administrators to forward MU traffic to a remote
network without modifying their network configuration and thereby enabling them to span their subnet
across the intermediate network. Each GRE tunnel however, must be on a unique subnet to function properly.
All data packets going from the configured WLAN to the GRE tunnel are forwarded to the mapped GRE tunnel
using GRE encapsulation. The other end of the GRE tunnel is responsible for removing the GRE header and
forwarding it to the destination IP.
The current implementation of GRE makes use of the management IP stack to route GRE encapsulated traffic.
Encapsulation and decapsulation is done in the user space, which affects the performance of the switch. All
the non-GRE packets continue to get forwarded as is.
GRE tunneling consists of three protocol types:
• Passenger—The protocol is encapsulated (IP)
• Carrier— GRE Protocol provides carrier services
• Transport—IP carries the encapsulated protocol.