Brocade BigIron RX Series Configuration Guide - Manual (Page 246)

168 BigIron RX Series Configuration Guide
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Configuring IP parameters
7
NOTE
The encapsulated packets sent on a GRE tunnel have the DF bit set. Setting a GRE tunnel MTU to
be greater than 1476 will cause the encapsulated packet to be greater than 1500 bytes. This may
cause the transit routers to drop the encapsulated packet if that transit router's IP MTU is 1500
bytes (a typical default MTU value) since transit routers can not fragment a GRE packet.
Configuring a GRE IP tunnel
To configure a GRE IP Tunnel, the following parameters must be configured:
• Tunnel interface
• Source Address for the Tunnel
• Destination address for the Tunnel
• GRE Encapsulation
• Loopback address for the Tunnel (required for de-encapsulation)
• IP address for the Tunnel
NOTE
Sustained rates of small packet sizes may affect the ability of a 10 gigabit Ethernet port to maintain
line rate GRE encapsulation and de-encapsulation performance.
Configuring a tunnel interface
To configure a tunnel interface, use the following command.
BigIron RX(config)# interface tunnel 1
BigIron RX(config-tnif-1)
Syntax: interface tunnel <tunnel-number>
The <tunnel-number> variable is numerical value that identifies the tunnel being configured.
Configuring a source address for a tunnel interface
To configure a source address for a specific tunnel interface, enter the following command.
BigIron RX(config)# interface tunnel 1
BigIron RX(config-tnif-1)tunnel source 35.0.8.108
Syntax: tunnel source <ip-address>
The <ip-address> variable is source IP address being configured for the specified tunnel.
Configuring a destination address for a tunnel interface
To configure a destination address for a specific tunnel interface, enter the following command.
BigIron RX(config)# interface tunnel 1
BigIron RX(config-tnif-1)tunnel destination 131.108.5.2
Syntax: tunnel destination <ip-address>
The <ip-address> variable is destination IP address being configured for the specified tunnel.