Interfaces

Type of interfaces:
Permanent interfaces: management and operations
management: ex fxp0 OOB user access ( SSH, telent
operational: ex fxp1 connects RE with PFE used by routing protocols pkts  and forward table updates

Transient interfaces
-are located on a PIC (Physical Interface Card) which is located on a FPC (Flexible PIC Concentrator)
Interface naming: media_type-fpc/pic/port.unit
Interface has: physical properties + logical properties
    Physical properties: description,encapsulation, MTU etc.
    Logical properties ~ units
units start from 0, some interface types can have only a logical unit ( ex: loopback)
definition: needs to have a family: (inet, inet6, iso, mpls)
protocol address: inet can have more protocol addresses

Interface Primary address:
lowest IP configured, used for sending traffic when destination address is not local
Interface Preferred address:
when an  interface has 2 addresses in the same subnet you can chose which one is preferred ( lowest is default)

How to set an interface:
# edit interface <interface-name>
# set description "The description is a physical interface properties"
# set unit 0 family inet  address <IP>/<SM>
*** if subnet is not specified is considered /32
*** loopback interfaces can be only /32




>show

>show interfaces

>show interfaces terse

>show interfaces terse | except down
show all interfaces that are up

 >show interfaces terse | match vlan |except down


 changes:
#set <interface-name> disable
is equivalent to shutdown  <interface> in Cisco
it puts the interface in Admin down
the configuration is still there
check with >show interface <interface-name> terse and see the interface is Adm Down
#delete set <interface-name> disable

#deactivate  <interface-name>  
disables the entire <interface-name> hierarchy, can be used not only for  interfaces, for any other parts of the hierarchy
the output  of show interface terse will still show  the interface as Admin Up
#activate  interface-name>