Specifications

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Cisco 7100 Series VPN Router Installation and Configuration Guide
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Chapter 4 Performing a Basic Startup Configuration
Configuring a Router
Configuring the Fast Ethernet Interfaces
The Cisco 7100 series VPN routers have two 10BaseT/100BaseTX autosensing Ethernet/Fast Ethernet
interfaces equipped with RJ-45 receptacles.
To configure the Fast Ethernet interfaces, use the duplex command and the speed command. To fully
enable autonegotiation on the Fast Ethernet interfaces, use the duplex auto command and the speed
auto command.
The default settings and the commands to change the defaults are listed in Table 4-1.
If the connected Fast Ethernet port does not support autonegotiation or is not configured for
autonegotiation, then the router uses a method called parallel detection which can determine speed, but
not duplex. In this case the autosensensing Fast Ethernet port on your Cisco 7100 series router will
default to half-duplex mode.
To configure the Fast Ethernet port 0, follow the steps below:
Step 1 At the Router (config)# prompt, enter the interface type slot/port command to enter the interface
configuration mode. In this example, Fast Ethernet port 0 is configured:
Router(config)# interface fastethernet 0/0
Router(config-if)#
You can now enter any changes to the configuration.
Note To see a list of the configuration commands available to you, enter ? at the prompt or press the Help key
while in configuration mode.
Step 2 Specify the IP address. The following example uses an IP address of 10.1.1.20:
Router(config-if)# ip address 10.1.1.20 255.0.0.0
Step 3 Change a default setting or configure other features on the interface, as needed.
The following example shows you how to change the duplex mode (autonegotiation is the default) and
the speed (autonegotiation is the default):
Router(config-if)# duplex half
Router(config-if)# speed 10
Note For more information on configuring interfaces, refer to the Cisco IOS Interface Configuration
Guide and the Cisco IOS Interface Command Reference publications. See “Related Documentation”
section on page xi for more information.
Table 4-1 Fast Ethernet Interface Defaults
Attribute Default Value Command
Duplex mode
Autonegotiation
1
1. In Cisco IOS Release 12.0(4)XE, the default value for duplex mode is half duplex and the default value for speed is 100 Mbps.
In Cisco IOS Release 12.0(5)XE or later releases of 12.0 XE, and in Cisco IOS Release 12.0(6)T or later releases of 12.0 T,
the default value for duplex mode and speed is autonegotiation.
duplex {full | half | auto}
no duplex
Speed Autonegotiation speed {10 | 100 | auto}
no speed