a) Operational Mode:
When we log in to the router and the CLI starts, we are at
the top level of the CLI operational mode. In this mode, we
enter the commands for
1. Controlling the CLI environment, and
2. Monitor and troubleshoot network connectivity, and
3. Initiating the Configuration Mode.
Frequently used commands in this mode include ping, show,
traceroute, configure, etc.
b) Configuration Mode:
We use the Configuration mode for configuring the JUNOS software
by creating a hierarchy of configuration statements. We enter
the configuration mode by using the command "configure" as shown
below:
user@host> configure
entering configuration mode
[edit]
user@host#
Issuing the commands one at a time using CLI can configure
a JUNOS™ router or alternately, we can configure by creating
a text (ASCII) file that contains the statement hierarchy. Remember
to activate the configuration by using the command "commit"
on the router.
As shown in the above example, the generic configuration
prompt is user@host#. Ofcourse, we can change the prompt tby
using appropriate command.
Statement Hierarchy:
We use the above configuration mode commands to create a
statement hierarchy, and then configure the JUNOS software.
The term "statement hierarchy" is used to define the
sequence of commands used for configuring a particular feature
(or features) of the router. An example statement hierarchy
is given below:
user@host> configure
entering configuration mode
[edit] ----Top level
user@host#edit protocols ospf
[edit protocols ospf] ----protocols ospf hierarchy level
user@host#
"set" commands are used to configure specific leaf
statements.
Ex.: user@host# set hello-interval 14
2. Router Interface Configuration:
a. Types of Interfaces
Juniper Networks platform has primarily two types of interface.
These are:
- Permanent interfaces, these are always present in the
router and
- Transient interfaces, these can be inserted or removed
from the router by user.
1. Permanent Interfaces:
Each router has two permanent interfaces. These are:
a. Management Ethernet interface: This interface enables
us to access the router using ssh, and telnet. The interface
uses out-of-band connectivity, and does not provide packet forwarding
capabilities for the transit data packets.
b. Internal Ethernet interface: Connects the Routing Engine
(running the JUNOS Internet software) to the Packet Forwarding
Engine. The router uses this interface as the main communications
link between the JUNOS software and the components of the Packet
Forwarding Engine. The Internal Ethernet interface is configured
automatically when the JUNOS software boots.
2. Transient Interfaces:
Transient Interfaces are the interfaces that receive user's
data packets from the network and transmit the packets to the
network. These interfaces are physically located on a Physical
Interface Card. They can be inserted and removed at any time.
These interface need to be configured before using it. We
can also configure the interfaces that are not in the chassis.
When the JUNOS software activates the router's configuration
it finds out the interfaces that are present and activates only
those interfaces.
In addition, each router has two serial ports, labeled console
and auxiliary. Console port can be used to connect tty-type
terminals to the router. The auxiliary port can connect to a
modem.
b. Interface Representation and Command
Syntax:
Using JUNOS software, a typical interface configuration will
have the following syntax:
media_type-fpc/pic/port.unit
media_type: is the one that uniquely identifies the
type of physical interface. It is a two-character word.
fpc: is the physical slot number in the chassis where
the interface is located.
Pic: is the slot number on the FPC where the interface
is located.
port: is the location on the PIC where the interface
port (to which the interface is connected) is located.
unit: is the logical portion of the interface that
is being configured.
Note: Some Physical interfaces use channel numbers
instead if unit numbers. These numbers are represented using
colon instead of period like media_type-fpc/pic/port:channel
Number
C. Examples of Router Interface Configuration:
Following are some of the examples that configure the JUNOS
software using CLI. Note that these are provided only to give
a broad idea, and not necessarily accurate.
Example 1: Configuring a hostname on a router.
user@host>configure
[edit]
user@host#edit system
[edit system]
user@host#set host-name juniper
[edit system]
user@juniper#
Example 2: Assigning an IP Address to a router interface.
user@host>configure
[edit]
user@host#edit interfaces so-0/0/0
[edit interfaces so-0/0/0]
user@host# edit unit 0
[edit interfaces so-0/0/0 unit 0]
user@juniper#edit family inet
[edit interfaces so-0/0/0 unit 0 family inet]
user@juniper#set address 192.168.1.1/24
[edit interfaces so-0/0/0 unit 0 family inet]
user@juniper#
3. RIP Configuration
using JUNOS.
user@host>configure
[edit]
user@host#edit protocols
[edit protocols]
user@host#edit rip
[edit protocols rip]
user@host#edit group neighbors
[edit protocols rip group neighbors]
user@host#set neighbor so-0/0/0.0;
[edit protocols rip group neighbors]
user@host#set neighbor so-0/0/1.0;
[edit protocols rip group neighbors]
user@host#
Further, configuring for RIP involves creation and application
of import/export policies. The same are not in the scope of
this tutorial and not included here.
