Gre Applications - 3Com MSR 50 Series Configuration Manual

3 The GRE module checks the key, checksum and sequence number, and then strips
off the GRE header and submits the payload to the IPX module.
4 The IPX module performs the subsequent forwarding processing for the packet.
n
Encapsulation and decapsulation processes on both ends of the GRE tunnel and
the resulting increase in data volumes will degrade the forwarding efficiency for
the GRE-enabled device to some extent.

GRE Applications

GRE supports these types of applications:
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Multi-protocol communications through a single-protocol backbone
Figure 440 Multi-protocol communications through a single-protocol backbone
Router A
In the example as shown in
running Novell IPX, while Team 1 and Team 2 are local networks running IP.
Through the GRE tunnel between Router A and Router B, Group 1 can
communicate with Group 2 and Team 1 can communicate with Team 2. They will
not interfere with each other.
"Multi-protocol communications through a single-protocol backbone" on
page 1591
"Scope enlargement of the network running a hop-limited protocol" on page
1592
"VPN creation by connecting discontinuous subnets" on page 1592
"GRE-IPSec tunnel application" on page 1592
Novell IPX protocol
Group 1
GRE tunnel
IP protocol
Team 1
Novell IPX protocol
Group 2
Internet
IP protocol
Team 2
Figure 440, Group 1 and Group 2 are local networks
GRE Overview 1591
Router B