Connect and share with interfaces

"Hi ho interfaces away!"

Any device in the world of networking must have interfaces. In this session we will talk about some aspects that interfaces on a Juniper router have:

• Types of interfaces
• Naming conventions
• Interface properties
• Configuration

Juniper routers have two flavors of interfaces, transient and permanent. You cannot remove permanent interfaces, but you can move and change out transient interfaces.

Let's talk more about the types of permanent interfaces and their uses:

On the M/T-Series routers two permanent interfaces exist:

Acronyms of the Moment:

OOB: Out of Band management (remote access to router)

SNMP: Simple Network Management Protocol

RP: multicast Rendezvous Point

For M and T-Series routers

• fxp0: Ethernet interface that can provide remote access to the router. You can send SNMP or syslog management messages over this interface Caution! fxp0 is a non-transit interface which means traffic cannot travel over this interface! Do not run any routing protocols on this interface.
• fxp1: This is an internal interface between the PFE and RE. This interface is never configured, but can be useful for router troubleshooting. This interface does not exist in the software driven J-Series platform.

Other types of interfaces created by the router at startup:

• lo0: Loopback interface of the router. The loopback interface is often assigned an address for management purposes or to allow the router to adapt to network or physical interface failures. When configured with a firewall filter, the loopback protects the router from attacks.
• sp: Service interface is used for Network Address Translation or NAT, IP Security (IPSec) and stateful firewalls
• pd: A de-encapsulation interface for PIMs so that PIM interface registers may be processed and allows the creation of a multicast Rendezvous Point. J-Series only
• pe: PIM encapsulation interface is used in multicast to create and send a unicast PIM register message to the Rendezvous Point or RP. J-Series only
• ip: used for IP over IP encapsulation and tunneling
• dsc: Discard interface used to silently discard packets. Used to ward off Denial of Service attacks or DoS.
• tap: Historically used in BSD systems for monitoring discarded packets but is no longer "officially" supported.

We will talk about transient interfaces next