Configuring and Verifying Unidirectional Links
This section contains two examples and commands that you can use to configure and verify unidirectional links:
Configuring and Verifying a Simple Example
To configure unidirectional link mode using default settings on 10-Gigabit Ethernet interface xe-5/1/0 and confirm the configuration:
The transmit-only and receive-only interfaces are created as soon as you commit the configuration. The following show command is one way to verify creation of these new interfaces:
user@host run show interfaces xe-5/1/0*
terseInterface Admin Link Proto Local Remote xe-5/1/0 up down xe-5/1/0-rx up down xe-5/1/0-tx up up
The two unidirectional physical interfaces, xe-5/1/0-rx and xe-5/1/0-tx, are now present. In this example, no fiber-optic cables are connected to the port; consequently the xe-5/1/0 and xe-5/1/0-rx link states are down. In contrast, xe-5/1/0 is in the up state, because the transmit-only link is always up.
The following sample output provides more information about each of the interfaces. Unidirectional link mode has been enabled on xe-5/1/0, the transmit-only and receive-only interfaces are present, and the link state matches expectations for no fiber-optic cables connected to the physical port.
user@host run show interfaces xe-5/1/0*Physical interface: xe-5/1/0, Enabled, Physical link is Down
Interface index: 318, SNMP ifIndex: 118
Link-level type: Ethernet, MTU: 1514, LAN-PHY mode, Speed: 10Gbps,
Unidirectional: Enabled, Loopback: None, Source filtering: Disabled,
Flow control: Enabled
Device flags : Present Running Down
Interface flags: Hardware-Down SNMP-Traps Internal: 0x4000
Link flags : None
CoS queues : 8 supported, 8 maximum usable queues
Current address: 00:05:85:75:8b:62, Hardware address: 00:05:85:75:8b:62
Last flapped : 2007-08-10 11:45:29 PDT (01:39:47 ago)
Active alarms : LINK
Active defects : LINK
PCS statistics Seconds
Bit errors 0
Errored blocks 0
Physical interface: xe-5/1/0-rx, Enabled, Physical link is Down
Interface index: 153, SNMP ifIndex: 129
Link-level type: Ethernet, MTU: 1514, LAN-PHY mode, Speed: 10Gbps,
Unidirectional: Rx-Only
Device flags : Present Running Down
Interface flags: Hardware-Down SNMP-Traps Internal: 0x4000
Link flags : None
CoS queues : 8 supported, 8 maximum usable queues
Current address: 00:05:85:75:8b:62, Hardware address: 00:05:85:75:8b:62
Last flapped : 2007-08-10 11:46:29 PDT (01:38:47 ago)
Input rate : 0 bps (0 pps)
Output rate : 0 bps (0 pps)
Active alarms : LINK
Active defects : LINK
PCS statistics Seconds
Bit errors 0
Errored blocks 0
Physical interface: xe-5/1/0-tx, Enabled, Physical link is Up
Interface index: 158, SNMP ifIndex: 130
Link-level type: Ethernet, MTU: 1514, LAN-PHY mode, Speed: 10Gbps,
Unidirectional: Tx-Only
Device flags : Present Running
Interface flags: SNMP-Traps Internal: 0x4000
Link flags : None
CoS queues : 8 supported, 8 maximum usable queues
Current address: 00:05:85:75:8b:62, Hardware address: 00:05:85:75:8b:62
Last flapped : 2007-08-10 11:46:29 PDT (01:38:47 ago)
Input rate : 0 bps (0 pps)
Output rate : 0 bps (0 pps)Configuring and Verifying a More Complex Example
The following example makes the following changes from a default configuration:
- Sets framing mode to WAN-PHY on the parent interface, and consequently on the unidirectional interfaces as well.
- Configures VLAN IDs, VLAN tagging for single VLAN, and IP addresses on both unidirectional interfaces.
- Sets a nondefault MAC address on the receive-only interface.
- Configures a static ARP entry on the transmit-only interface. The entry contains a MAC address that is put into the Ethernet header destination address field of transmitted frames.
CLI Quick Configuration
To quickly configure the example described, copy the following commands and paste them into the router terminal window:
Configuration Results
Display the results of the configuration:
Detailed Interface Information
To display terse details about the interfaces:
user@host run show interfaces xe-5/1/0*
terseInterface Admin Link Proto Local Remote
xe-5/0/0 up up
xe-5/0/0-rx up up
xe-5/0/0-rx.102 up up inet 1.1.102.2/24
multiservice
xe-5/0/0-rx.32767 up up multiservice
xe-5/0/0-tx up up
xe-5/0/0-tx.201 up up inet 2.2.201.2/24
multiservice
xe-5/0/0-tx.32767 up up multiserviceThe additional logical interfaces for the unidirectional links result from the unit and VLAN tagging configuration.
To display more information about the interfaces:
user@host run show interfaces xe-5/1/0*Physical interface: xe-5/1/0, Enabled, Physical link is Down
Interface index: 151, SNMP ifIndex: 116
Link-level type: Ethernet, MTU: 1514, Clocking: Internal, WAN-PHY mode, Speed: OC192, Unidirectional: Enabled, Loopback: None,
Source filtering: Disabled, Flow control: Enabled
Device flags : Present Running Down
Interface flags: Hardware-Down SNMP-Traps Internal: 0x4000
Link flags : None
CoS queues : 8 supported, 8 maximum usable queues
Current address: 00:05:85:75:8b:39, Hardware address: 00:05:85:75:8b:39
Last flapped : 2007-08-10 08:50:40 PDT (00:05:00 ago)
Active alarms : LOF, LINK
Active defects : LOF, SEF, AIS-L, AIS-P, LINK
PCS statistics Seconds
Bit errors 0
Errored blocks 0
Physical interface: xe-5/1/0-rx, Enabled, Physical link is Down
Interface index: 153, SNMP ifIndex: 114
Link-level type: Ethernet, MTU: 1518, WAN-PHY mode, Speed: OC192, Unidirectional: Rx-Only
Device flags : Present Running Down
Interface flags: Hardware-Down SNMP-Traps Internal: 0x4000
Link flags : None
CoS queues : 8 supported, 8 maximum usable queues
Current address: 00:12:34:56:78:90, Hardware address: 00:05:85:75:8b:39
Last flapped : 2007-08-10 08:50:40 PDT (00:05:00 ago)
Input rate : 0 bps (0 pps)
Output rate : 0 bps (0 pps)
Active alarms : LOF, LINK
Active defects : LOF, SEF, AIS-L, AIS-P, LINK
PCS statistics Seconds
Bit errors 0
Errored blocks 0
Logical interface xe-5/1/0-rx.102 (Index 70) (SNMP ifIndex 115)
Flags: Device-Down SNMP-Traps 0x4000 VLAN-Tag [ 0x8100.102 ] Encapsulation: ENET2
Input packets : 0
Output packets: 0
Protocol inet, MTU: 1500
Addresses, Flags: Dest-route-down Is-Preferred Is-Primary
Destination: 10.1.102/24, Local: 10.1.102.2, Broadcast: 10.1.102.255
Protocol multiservice, MTU: Unlimited
Flags: None
Logical interface xe-5/1/0-rx.32767 (Index 71) (SNMP ifIndex 124)
Flags: Device-Down SNMP-Traps 0x4000 VLAN-Tag [ 0x0000.0 ] Encapsulation: ENET2
Input packets : 0
Output packets: 0
Protocol multiservice, MTU: Unlimited
Flags: None
Physical interface: xe-5/1/0-tx, Enabled, Physical link is Up
Interface index: 158, SNMP ifIndex: 125
Link-level type: Ethernet, MTU: 1518, WAN-PHY mode, Speed: OC192, Unidirectional: Tx-Only
Device flags : Present Running
Interface flags: SNMP-Traps Internal: 0x4000
Link flags : None
CoS queues : 8 supported, 8 maximum usable queues
Current address: 00:05:85:75:8b:39, Hardware address: 00:05:85:75:8b:39
Last flapped : 2007-08-10 08:50:40 PDT (00:05:00 ago)
Input rate : 0 bps (0 pps)
Output rate : 0 bps (0 pps)
Logical interface xe-5/1/0-tx.201 (Index 72) (SNMP ifIndex 126)
Flags: SNMP-Traps 0x4000 VLAN-Tag [ 0x8100.201 ] Encapsulation: ENET2
Input packets : 0
Output packets: 0
Protocol inet, MTU: 1500
Addresses, Flags: Is-Preferred Is-Primary
Destination: 10.2.201/24, Local: 10.2.201.2, Broadcast: 10.2.201.255
Protocol multiservice, MTU: Unlimited
Flags: None
Logical interface xe-5/1/0-tx.32767 (Index 73) (SNMP ifIndex 127)
Flags: SNMP-Traps 0x4000 VLAN-Tag [ 0x0000.0 ] Encapsulation: ENET2
Input packets : 0
Output packets: 0
Protocol multiservice, MTU: Unlimited
Flags: NoneYou can use the show interfaces xe-5/1/0* extensive command to display the most complete set of information about the interfaces. Alternatively, you can specify only xe-5/1/0, xe-5/1/0-rx, or xe-5/1/0-tx to show extensive information about just one interface.
The extensive output includes statistics for the interfaces. The following excerpts show the differences between the receive-only and transmit-only interfaces for statistics.
In the following output for a receive-only interface, input statistics are recorded, but all output statistics have a value of zero.
user@host show interfaces xe-7/0/0-rx
extensivePhysical interface: xe-7/0/0-rx, Enabled, Physical link is Up
Interface index: 174, SNMP ifIndex: 118, Generation: 175
Link-level type: Ethernet, MTU: 1514, LAN-PHY mode, Speed: 10Gbps, Unidirectional: Rx-Only
Device flags : Present Running
Interface flags: SNMP-Traps Internal: 0x4000
Link flags : None
CoS queues : 8 supported, 8 maximum usable queues
Hold-times : Up 0 ms, Down 0 ms
Current address: 00:05:85:73:e4:83, Hardware address: 00:05:85:73:e4:83
Last flapped : 2007-06-01 09:08:22 PDT (3d 02:31 ago)
Statistics last cleared: Never
Traffic statistics:
Input bytes : 322857456303482 9627496104 bps
Output bytes : 0 0 bps
Input packets: 328775413751 1225495 pps
Output packets: 0 0 pps
...
Filter statistics:
Input packet count 328775015056
Input packet rejects 1
Input DA rejects 0
...
Logical interface xe-7/0/0-rx.0 (Index 72) (SNMP ifIndex 120) (Generation 138)
Flags: SNMP-Traps Encapsulation: ENET2
Traffic statistics:
Input bytes : 322857456303482
Output bytes : 0
Input packets: 328775413751
Output packets: 0
...
Transit statistics:
Input bytes : 322857456303482 9627496104 bps
Output bytes : 0 0 bps
Input packets: 328775413751 1225495 pps
Output packets: 0 0 pps
...
In the following output for a transmit-only interface, output statistics are recorded, but all input statistics have a value of zero.
user@host> show interfaces xe-7/0/0-tx extensivePhysical interface: xe-7/0/0-tx, Enabled, Physical link is Up
Interface index: 176, SNMP ifIndex: 137, Generation: 177
Link-level type: Ethernet, MTU: 1514, LAN-PHY mode, Speed: 10Gbps, Unidirectional: Tx-Only
Device flags : Present Running
Interface flags: SNMP-Traps Internal: 0x4000
Link flags : None
CoS queues : 8 supported, 8 maximum usable queues
Hold-times : Up 0 ms, Down 0 ms
Current address: 00:05:85:73:e4:83, Hardware address: 00:05:85:73:e4:83
Last flapped : 2007-06-01 09:08:19 PDT (3d 02:31 ago)
Statistics last cleared: Never
Traffic statistics:
Input bytes : 0 0 bps
Output bytes : 322891152287160 9627472888 bps
Input packets: 0 0 pps
Output packets: 328809727380 1225492 pps
...
Filter statistics:
Output packet count 328810554250
Output packet pad count 0
Output packet error count 0
...
Logical interface xe-7/0/0-tx.0 (Index 73) (SNMP ifIndex 138) (Generation 139)
Flags: SNMP-Traps Encapsulation: ENET2
Traffic statistics:
Input bytes : 0
Output bytes : 322891152287160
Input packets: 0
Output packets: 328809727380
...
Transit statistics:
Input bytes : 0 0 bps
Output bytes : 322891152287160 9627472888 bps
Input packets: 0 0 pps
Output packets: 328809727380 1225492 pps
...
Related Topics
For more information about concepts associated with unidirectional links, see the following resource:
- RFC 3077, A Link-Layer Tunneling Mechanism for Unidirectional Links