Step 2
Enable Layer 2 topology detection.
[Router]
l2-topology detect enable
Step 3
Restart Ethernet 0/0/0 and view changes of ARP entries and aging time.
# View ARP entries on the Router. You can see that the Router has learned the MAC address
of the PC.
[Router]
display arp all
IP ADDRESS MAC ADDRESS EXPIRE(M) TYPE INTERFACE VPN-
INSTANCE
VLAN/CEVLAN PVC
-----------------------------------------------------------------------------
10.1.1.2 00e0-c01a-4900 I - Vlanif100
10.1.1.1 00e0-c01a-4901 20 D-0 Ethernet0/0/0
10.1.1.3 00e0-de24-bf04 20 D-0 Ethernet0/0/1
-----------------------------------------------------------------------------
Total:3 Dynamic:2 Static:0 Interface:1
# Run the
shutdown
and
undo shutdown
commands on Ethernet0/0/0 and view the aging time
of ARP entries.
[Router]
interface ethernet 0/0/0
[Router-Ethernet0/0/0]
shutdown
[Router-Ethernet0/0/0]
undo shutdown
[Router-Ethernet0/0/0]
display arp all
IP ADDRESS MAC ADDRESS EXPIRE(M) TYPE INTERFACE VPN-INSTANCE
VLAN/CEVLAN PVC
----------------------------------------------------------------------------
10.1.1.2 00e0-c01a-4900 I -
Vlanif100
10.1.1.3 00e0-de24-bf04 0 D-0 Ethernet0/0/1
------------------------------------------------------------------------------
Total:2 Dynamic:1 Static:0 Interface:1
NOTE
According to the preceding information, the ARP entries learned from Ethernet0/0/1 are deleted after
Ethernet0/0/0 is shut down. After Ethernet0/0/0 is enabled and becomes Up, the aging time of ARP entries
learned from Ethernet0/0/1 changes to 0.
# When the aging time is 0, the Router sends an ARP probe packet for updating ARP entries.
[Router-Ethernet0/0/0]
display arp all
IP ADDRESS MAC ADDRESS EXPIRE(M) TYPE INTERFACE VPN-INSTANCE
VLAN/CEVLAN
----------------------------------------------------------------------------
10.1.1.2 00e0-c01a-4900 I -
Vlanif100
10.1.1.3 00e0-de24-bf04 20 D-0 Ethernet0/0/1
----------------------------------------------------------------------------
Total:2 Dynamic:1 Static:0 Interface:1
NOTE
After ARP entries are updated, the aging time is restored to be the default value, 1200s.
----End
Configuration Files
Configuration file of the Router
#
sysname Router
#
l2-topolgy detect enable
Huawei AR150&200 Series Enterprise Routers
Configuration Guide - IP Service
1 ARP Configuration
Issue 02 (2012-03-30)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
36