Configuration Tasks

To configure a POS interface:

1. Configure a physical interface.

   host1(config)#interface pos 0/1

2. (Optional) Assign a text description or an alias to the interface.

   host1(config-if)#pos description austin01 pos interface

3. Configure the encapsulation method.

   host1(config-if)#encapsulation ppp

4. (Optional) Configure the internal clock source.

   host1(config-if)#clock source internal module

5. (Optional) Set the size of the CRC.

   host1(config-if)#crc 32

6. (Optional) Set the time interval at which the router calculates bit and packet rate counters.

   host1(config-if)#load-interval 90

7. (Optional) Set the type of loopback mode.

   host1(config-if)#loopback line

8. (Optional) Set the MRU size.

   host1(config-if)#mru 1000

9. (Optional) Set the MTU size.

   host1(config-if)#mtu 1000

10. (Optional) Set the type of framing.

    host1(config-if)#pos framing sdh

11. Disable payload scrambling.

    host1(config-if)#no pos scramble-atm

12. (Optional) Disable an interface.

    host1(config-if)#shutdown

clock source

• Use to set the clock source.
• You can set internal or line clocking.
• Internal clocking has two options:
  • module—Uses internal clock from the line module
  • chassis—Uses the configured router clock
• Example

  host1(config-if)#clock source internal module

• Use the no version to restore the default value, line.
• See clock source.

crc

• Use to set the number of bits used for CRC checking.
• CRC is an error-checking technique that uses a calculated numeric value to detect errors in transmitted data; 16 and 32 indicate the number of check digits per frame that are used to calculate the frame check sequence (FCS). Both the sender and receiver must use the same setting.
• Example

  host1(config-if)#crc 32

• Use the no version to restore the default value, 16.
• See crc.

encapsulation frame-relay ietf

• Use to specify Frame Relay as the encapsulation method for the interface.
• The router uses IETF format (RFC 2427 encapsulation).
• Example

  host1(config-if)#encapsulation frame-relay ietf

• Use the no version to remove the Frame Relay configuration from an interface.
• See encapsulation frame-relay ietf

encapsulation ppp

• Use to specify PPP as the encapsulation method for the interface.
• Example

  host1(config-if)#encapsulation ppp

• Use the no version to remove the PPP configuration from an interface.
• See encapsulation ppp.

interface pos

• Use to configure a POS interface.
• To specify a POS interface for ERX-7xx models, ERX-14xx models, and ERX-310 routers, use the slot/port[.subinterface ] format.
  • slot—Number of the chassis slot
  • port—Port number on the I/O module
  • subinterface—Number of the subinterface
• To specify a POS interface for E120 and E320 routers, use the slot/adapter/port format.
  • slot—Number of the chassis slot
  • adapter—Identifier for the IOA within the E320 chassis, either 0 or 1, where:
    • 0 indicates that the IOA is installed in the right IOA bay (E120 router) or the upper IOA bay (E320 router).
    • 1 indicates that the IOA is installed in the left IOA bay (E120 router) or the lower IOA bay (E320 router).
  • port—Port number on the IOA
• For more information about modules that support POS interfaces, see chapter Configuring Unchannelized OCx/STMx Interfaces in JUNOSe Physical Layer Configuration Guide.
• Examples

  host1(config-if)#interface pos 0/1

  host1(config-if)#interface pos 5/0/0

• Use the no version to remove the POS interface.
• See interface pos.

load-interval

• Use to set the time interval at which the router calculates bit and packet rate counters.
• You can choose a multiple of 30 seconds, in the range 30–300 seconds.
• Example

  host1(config-if)#load-interval 90

• Use the no version to restore the default value, 300.
• See load-interval.

loopback

• Use to specify the type of loopback for a POS interface.
  • internal—Connects the local transmitted signal to the local received signal.
  • line—Connects the received network signal directly to the transmit network signal. When configured in line loopback mode, the router never receives data from the network.
• Example

  host1(config-if)#loopback line

• Use the no version to clear the loopback.
• See loopback.

mru

• Use to set the maximum allowable size of the MRU.
• Specify a value in the range 1–9996 bytes.
• Example

  host1(config-if)#mru 1000

• Use the no version to restore the default value, 4470.
• See mru.

mtu

• Use to set the maximum allowable size of the MTU.
• Specify a value in the range 1–9996 bytes.
• Example

  host1(config-if)#mtu 1000

• Use theno version to restore the default value, 4470.
• See mtu.

pos description

• Use to assign a text description or an alias to a POS HDLC interface.
• You can use this command to help you identify the interface and keep track of interface connections.
• The description or alias can be a maximum of 80 characters.
• Use the show interfaces pos command to display the text description.
• Example

  host1(config-if)#pos description austin01 pos interface

• Use the no version to remove the text description or alias.
• See pos description.

pos framing

• Use to set the type of framing for a POS interface.
  • sdh—Uses SDH framing format
  • sonet—Uses SONET framing format (the default)
• Example

  host1(config-if)#pos framing sdh

• Use the no version to restore the default value, sonet.
• See pos framing.

pos scramble-atm

• Use to enable payload scrambling on a POS interface.
• Payload scrambling is enabled by default. When enabled, both sides of the connection must be using the scrambling algorithm. The router uses a 43rd-order synchronous scrambler to scramble the output data.
• Example

  host1(config-if)#pos scramble-atm

• Use the no version to disable scrambling on the POS interface.
• See pos scramble-atm.

shutdown

• Use to disable a POS interface.
• Example

  host1(config-if)#shutdown

• Use the no version to restart a disabled interface.
• See shutdown.

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