Appendix A: Interface Configuration Examples

Introduction to the Junos Operating System

This Appendix Discusses:

•The interface configuration hierarchy;

•Configuration examples for various interface types; and

•Configuration groups.

Introduction to the Junos Operating System

Review of the Interface Configuration Hierarchy

The slide lists the topics we cover in this chapter. We discuss the highlighted topic first.

Introduction to the Junos Operating System

Physical Properties

The following list provides details for some physical interface properties:

•Data Link Layer protocol and keepalives: You can change the Data Link Layer protocol for the particular media type (for example, PPP to Cisco HDLC), and you can turn keepalives on or off;

•Link mode: On Ethernet interfaces you can hardcode the duplex setting to either half-duplex or full-duplex;

•Speed: You can specify the link speed on certain interface types;

•Maximum transmission unit (MTU): You can vary the size from 256 to 9192 bytes;

•Clocking: Refers to the interface clock source—either internal or external;

•Scrambling: Refers to payload scrambling, which can be on or off;

•Frame check sequence (FCS): You can modify to 32-bit mode (the default is 16-bit mode); and

•Diagnostic characteristics: You can enable local or remote loopbacks or set up a BERT test.

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A–4 • Interface Configuration Examples www.juniper.net

Introduction to the Junos Operating System

Logical Properties

The following list provides details for some logical interface properties:

•Protocol family: Refers to the protocol family you want to use, such as family inet, inet6, iso, mpls, or ethernet-switching;

•Addresses: Refers to the address associated with the particular family (for example, IP address using family inet);

•Virtual circuits: Refers to the virtual circuit identifier, such as a data-link connection identifier (DLCI), virtual path identifier (VPI), virtual channel identifier (VCI), or virtual LAN (VLAN) tag; and

•Other characteristics: Some other configurable options include Inverse ARP, traps, and accounting profiles.

Introduction to the Junos Operating System

Configuration Hierarchy

All interfaces have the same configuration hierarchy organization. The Junos operating system considers all properties defined directly under the interface name to be the physical properties of that interface. The unit number represents a particular logical interface or subinterface. The Junos OS considers all properties defined directly under the unit number to be the logical properties of each particular subinterface.