R3303-HP HSR6800 Routers Interface Command Reference
Table Of Contents
- Title Page
- Contents
- Ethernet interface configuration commands
- General Ethernet interface and subinterface configuration commands
- bandwidth
- combo enable
- description
- display counters
- display counters rate
- display interface
- display packet-drop interface
- display packet-drop summary
- duplex
- flag sdh
- flow-interval
- interface
- ip fast-forwarding
- link-delay
- loopback
- port link-mode
- port link-mode interface-list
- port-mode
- reset counters interface
- reset packet-drop interface
- shutdown
- speed
- sub-interface rate-statistic
- Layer 2 Ethernet interface and subinterface configuration commands
- broadcast-suppression
- display loopback-detection
- display port-group manual
- display storm-constrain
- flow-interval
- group-member
- jumboframe enable
- loopback-detection action
- loopback-detection control enable
- loopback-detection enable
- loopback-detection interval-time
- loopback-detection multi-port-mode enable
- loopback-detection per-vlan enable
- mdi
- multicast-suppression
- port-group manual
- speed auto
- storm-constrain
- storm-constrain control
- storm-constrain enable log
- storm-constrain enable trap
- storm-constrain interval
- unicast-suppression
- virtual-cable-test
- Layer 3 Ethernet interface and subinterface configuration commands
- General Ethernet interface and subinterface configuration commands
- ATM interface configuration commands
- WAN interface configuration commands
- Common WAN interface configuration commands
- Serial interface configuration commands
- Basic CE1 interface configuration commands
- Alarm
- cable (CE1 interface)
- channel-set (CE1 interface)
- clock (CE1 interface)
- clock-change auto
- code (CE1 interface)
- controller e1
- crc
- data-coding (CE1 interface)
- detect-ais
- display controller e1
- error-diffusion restraint config
- error-diffusion restraint enable
- frame-format (CE1 interface)
- idlecode (CE1 interface)
- itf (CE1 interface)
- loopback (CE1 interface)
- reset counters controller e1
- using (CE1 interface)
- Basic CT1 interface configuration commands
- alarm (CT1 interface)
- alarm-threshold
- bert (CT1 interface)
- cable (CT1 interface)
- channel-set (CT1 interface)
- clock (CT1 interface)
- code (CT1 interface)
- controller t1
- crc
- data-coding (CT1 interface)
- display controller t1
- error-diffusion restraint config
- error-diffusion restraint enable
- fdl
- frame-format (CT1 interface)
- idlecode (CT1 interface)
- itf (CT1 interface)
- loopback (CT1 interface)
- reset counters controller t1
- sendloopcode
- E1-F interface configuration commands
- T1-F interface configuration commands
- Basic CE3 interface configuration commands
- Basic CT3 interface configuration commands
- alarm (CT3 interface)
- bert (CT3 interface)
- cable (CT3 interface)
- clock (CT3 interface)
- controller t3
- crc
- display controller t3
- feac
- frame-format (CT3 interface)
- ft3
- link-delay
- loopback (CT3 interface)
- mdl (CT3 interface)
- reset counters controller t3
- t1 alarm
- t1 bert
- t1 channel-set
- t1 sendloopcode
- t1 set clock
- t1 set fdl
- t1 set frame-format
- t1 set loopback
- t1 show
- t1 shutdown
- t1 unframed
- using (CT3 interface)
- POS interface configuration commands
- CPOS interface configuration commands
- bandwidth
- clock
- controller cpos
- description
- display controller cpos
- display controller cpos e1
- display controller cpos e3
- display controller cpos t1
- display controller cpos t3
- e1 channel-set
- e1 set clock
- e1 set flag
- e1 set frame-format
- e1 set loopback
- e1 shutdown
- e1 unframed
- e3 set clock
- e3 set loopback
- e3 set national-bit
- e3 shutdown
- fe3
- flag
- flag vc-3
- flag vc-4
- frame-format
- ft3
- link-delay
- loopback
- multiplex mode
- ppp mp soft-binding
- reset counters controller cpos
- shutdown
- t1 channel-set
- t1 set clock
- t1 set flag
- t1 set frame-format
- t1 set loopback
- t1 shutdown
- t1 unframed
- t3 set alarm
- t3 set bert pattern
- t3 set clock
- t3 set feac
- t3 set frame-format
- t3 set loopback
- t3 set mdl
- threshold
- using e3
- using t3
- E-CPOS interace configuration commands
- Loopback and null interface configuration commands
- Support and other resources
- Index
39
Usage guidelines
When a hybrid or trunk port detects a loop condition, it sends traps, whether loopback detection control
is enabled or not. However, the port performs the protective action that you configure with the
loopback-detection action command only after loopback detection control is enabled.
This command is not applicable to access ports.
Examples
# Enable loopback detection control on the trunk port GigabitEthernet 4/0/1.
<Sysname> system-view
[Sysname] loopback-detection enable
[Sysname] interface gigabitethernet 4/0/1
[Sysname-GigabitEthernet4/0/1] port link-type trunk
[Sysname-GigabitEthernet4/0/1] loopback-detection enable
[Sysname-GigabitEthernet4/0/1] loopback-detection control enable
loopback-detection enable
Use loopback-detection enable to enable loopback detection globally in system view or on interfaces in
Ethernet interface or port group view. To use loopback detection on an Ethernet interface, you must
enable the function both globally and on the port.
Use undo loopback-detection enable to disable loopback detection globally or on Ethernet interfaces.
Syntax
loopback-detection enable
undo loopback-detection enable
Default
Loopback detection is disabled on all Ethernet interfaces.
Views
System view, Layer 2 Ethernet interface view, port group view
Default command level
2: System level
Usage guidelines
The undo loopback-detection enable command in system view disables loopback detection on all
interfaces.
If an interface receives a packet that it sent out, a loop has occurred. Loops might cause broadcast storms,
which degrade network performance. You can enable loopback detection to detect loops on an
interface and, if the interface supports the loopback-detection action command, configure the protective
action to take (for example, shut down the port) when a loop is detected.
In addition to the configured protective action, the device also performs other actions to alleviate the
impact of the loops. For more information, see Table 12.