Technical Documentation

Interface Naming

Each interface has the following components:

  • An interface name that specifies the media type
  • The slot where the FPC is located
  • The location of the PIC on the FPC
  • The PIC port

The interface name uniquely identifies an individual network connector in the system. You use the interface name when configuring interfaces and when enabling various functions and properties, such as routing protocols, on individual interfaces. The system uses the interface name when displaying information about the interface, for example, in the show interfaces command.

The interface name is represented by a physical part, a logical part, and a channel part in the following format:

physical<: channel >.logical

The channel part of the name is optional for all interfaces except Channelized DS3, E1, OC12, and STM1. For more information about channelized interfaces, see the JUNOS Network Interfaces Configuration Guide.

Physical Part of an Interface Name

The physical part of an interface name identifies the physical device, which corresponds to a single physical network connector. This part of the interface name has the following format:

type-fpc/pic/port

type is the media type, which identifies the network device. See Interface Types Supported by the JUNOS Software for information on supported interface types.

fpc identifies the number of the FPC card on which the physical interface is located. Specifically, it is the number of the slot in which the FPC card is installed. M40, M40e, M160, M320, T320, and T640 platforms each have eight FPC slots that are numbered from 0 through 7 from left to right as you are facing the front of the chassis. The M20 routing platform has four FPC slots that are numbered from 0 through 3 from top to bottom as you are facing the front of the chassis. The slot number is printed adjacent to each slot. The M5, M7i, M10, and M10i routing platforms do not use FPCs; you install the PICs individually. The M5 and M7i routing platforms have space for up to four PICs. The M7i routing platform also comes with an integrated Tunnel PIC or an optional integrated AS PIC. The M10 and M10i routing platforms have space for up to eight PICs.

pic identifies the number of the PIC card on which the physical interface is located. Specifically, it is the number of the PIC location on the FPC. The four PIC slots are numbered from 0 through 3. The PIC location is printed on the FPC carrier board. For PICs that occupy more than one PIC location, use the lower location number.

port identifies a specific port on a PIC. The number of ports varies depending on the PIC. The port slot numbers are printed on the PIC.

Logical Part of an Interface Name

The logical unit part of the interface name corresponds to the logical unit number, which can be a number in the range from 0 through 16,384.

Separators in Interface Names

There is a separator of some type between each element of an interface name.

In the physical part of the name, a hyphen (-) separates the media type from the FPC number, and a slash (/) separates the FPC, PIC, and port numbers.

In the virtual part of the name, a period (.) separates the channel and logical unit numbers.

A colon (:) separates the physical and virtual parts of the interface name.

Examples: Interface Names

This section provides examples of naming interfaces. See Figure 1 for an example of where the slots, PICs, and ports are located on the M40 router. Examine your PIC to determine the port numbers; all port numbers are marked on the PIC.

Figure 1: Interface Slot, PIC, and Port Locations

Image h1415.gif

For an FPC in slot 1 with two OC3 SONET PICs in PIC positions 0 and 1, each PIC with two ports uses the following names:

so-1/0/0.0so-1/0/1.0so-1/1/0.0so-1/1/1.0

An OC48 SONET FPC in slot 1 and in concatenated mode appears as a single FPC with a single PIC, which has a single port. If this interface has a single logical unit, the name is as follows:

so-1/0/0.0

An OC48 SONET FPC in slot 1 and in channelized mode has a number for each channel. For example:

so-1/0/0:0so-1/0/0:1

For an FPC in slot 1 with a Channelized OC12 PIC in PIC position 2, the DS3 channels have the following names:

t3-1/2/0:0t3-1/2/0:1t3-1/2/0:2...t3-1/2/0:11

For an FPC in slot 1 with four OC12 ATM PICs (the FPC is fully populated), the four PICs, each with a single port and a single logical unit, have the following names:

at-1/0/0.0at-1/1/0.0at-1/2/0.0at-1/3/0.0

Channelized DS3 to DS0 Interface Naming

You can configure 28 T1 channels for each T3 interface. Each T1 link can have up to eight DS0 channel groups, and each channel group can hold any combination of DS0 time slots. To specify the T1 link and DS0 channel group number in the interface name, use colons (:) as separators. For example, a Channelized DS3 to DS0 PIC might have the following physical and virtual interfaces:

DS0/0/0: x : y

where x is a T1 link ranging from 0 through 27, and y is a DS0 channel group ranging from 0 through 7. See the JUNOS Network Interfaces Configuration Guide for more information about ranges.

Channelized DS3 to DS1 Interface Naming

You can configure 28 T1 channels per T3 interface, and each interface can have logical interfaces. To specify the channel number, include it after the colon (:) in the interface name. For example, a 4-port T3 PIC in FPC 1 and slot 1 will have the following physical interfaces, depending on the media type:

t1-1/1/0: x t1-1/1/1: x t1-1/1/2: x t1-1/1/3: x

x is a channel number ranging from 0 through 27.

Channelized Intelligent Queuing Interface Naming

Channelized interfaces enable you to configure a number of individual channels that subdivide the bandwidth of a larger interface and minimize the number of PICs that an installation requires.

Note: Channelized IQ interfaces require M-series Enhanced FPCs.

Wherever the JUNOS documentation refers to channelized interfaces and PICs without the “intelligent queuing” or “IQ” descriptor, they are referring to the original channelized interfaces and PICs.

You can configure each port of a channelized IQ PIC as a single interface that uses the entire available bandwidth, or partition each port into smaller data channels. Following are the interface names associated with channelized IQ PICs:

  • coc12-fpc/pic/port—On a Channelized OC12 IQ PIC
  • coc1-fpc/pic/port:channel—On a Channelized OC12 IQ PIC
  • ct3-fpc/pic/port<:channel>—On a Channelized OC12 IQ PIC or a Channelized DS3 IQ PIC
  • cstm1-fpc/pic/port—On a Channelized STM1 IQ PIC
  • cau4-fpc/pic/port:channel—On a Channelized STM1 IQ PIC
  • ct1-fpc/pic/port<:channel>—On a Channelized OC12 IQ PIC or a Channelized DS3 IQ PIC
  • ce1-fpc/pic/port<:channel>—On a Channelized E1 IQ PIC or a Channelized STM1 IQ PIC
  • e1-fpc/pic/port<:channel>—E1 channels configured on a Channelized E1 IQ or a Channelized STM1 IQ PIC
  • ds-fpc/pic/port<:channel> Nx DS0 channels configured on a Channelized OC12 IQ PIC, Channelized STM1 IQ PIC, Channelized DS3 IQ PIC, or Channelized E1 IQ PIC
  • so-fpc/pic/port<:channel>—SONET/SDH channels configure four OC3 channels on a Channelized OC12 IQ PIC, one OC12 channel on a Channelized OC12 IQ PIC, or one STM1 channel on a Channelized STM1 IQ PIC
  • t1-fpc/pic/port<:channel>—T1 channels configured on a Channelized OC12 IQPIC or a Channelized DS3 IQ PIC
  • t3-fpc/pic/port<:channel>—T3 channels configured on a Channelized OC12 IQ PIC or a Channelized DS3 IQ PIC

How Interface Configurations Are Displayed

When you display a configuration, using either the show command in configuration mode or the show configuration top-level command, interfaces are listed in numerical order as follows:

  • From lowest to highest slot number
  • From lowest to highest PIC number
  • From lowest to highest port number

Published: 2010-01-29