Definition
IP-Link enables the FW to regularly send probe packets to a specific destination IP address and determines whether faults occur based on the reply packets.
After the FW does not receive any response packet within three probe intervals (15s by default) after sending three probe packets, the FW considers the current link to be faulty, and the IP-Link status is Down. The FW performs operations for the IP-Link Down event, such as the active/standby switchover of hot standby.
After the link recovers from the fault, the FW considers that the link fault is cleared only after it receives three consecutive response packets. Then the IP-Link status becomes Up. That is, the IP-Link status does not immediately become Up after the link fault is rectified. Instead, it becomes Up after three probe intervals (15s by default).
Configuring IP-Link Using the CLI
This section describes how to configure IP-link.
Context
IP-link, automatic service link reachability detection, detects the status of the links indirectly connected to the FW to ensure service continuity.
Procedure
1. Access the system view.
system-view
2. Enable the IP-link check function.
ip-link check enable
3. Set up an IP-link and access the IP-link view.
ip-link name ip-link-name [ vpn-instance vpn-instance-name ]
4. Configure the destination IPv4 address or domain name for IP-link.
USG6000: destination { ip-address | domain-name } [ interface interface-type interface-number ] [ mode { icmp [ next-hop { nexthop-address | dhcp | dialer } ] | arp } ]
USG9500: destination { ipv4-address | domain-name } [ interface interface-type interface-number ] [ next-hop nexthop-ipv4-address ] and ipv6 destination { ipv6-address | domain-name } [ interface interface-type interface-number ] [ next-hop nexthop-ipv6-address ]
5. Configure the destination IPv6 address or domain name for IP-link.
USG6000: ipv6 destination { ipv6-address | domain-name } [ interface interface-type interface-number ] [ mode { icmp6 [ next-hop nexthop-ipv6-address ] | ns } ]
USG9500: ipv6 destination { ipv6-address | domain-name } [ interface interface-type interface-number ] [ next-hop nexthop-ipv6-address ]
6. Configure the source address for IP-link.
source-ip
7. Configure the IP-link detection interval.
tx-interval interval
8. Configure the maximum number of IP-link detection timeout failures.
times times
The FW sends a detection packet every interval seconds. If the FW does not receive any response packet after sending times packets, the FW considers the detected link to be faulty.
9. Configure the minimum number of UP members affecting IP-link status.
least active-linknumber link-number
The minimum number of UP members affecting IP-link status needs to be configured when IP-link is used to detect multiple destination addresses or domain names. If the actual number of detected destination addresses or domain names is lower than the minimum number, the IP-link becomes down.
Follow-up Procedure
Run the display ip-link verbose command to view the detailed information about IP-link.
<sysname> display ip-link verbose
Current Total Ip-link Number : 1
-------------------------------------------------------------------------------
Name : test
Index : 2
Enable Flag : 1
Vrf : public/0
Member Number : 2
Tx-interval (default is 5) : 5
Times (default is 3) : 3
Least active-linknumber (default is 1) : 1
State : up
Init State Number : 0
DOWN State Number : 0
UP State Number : 2
-------------------------------------------------------------------------------
State : up
Destination Type/Destination Info : IP/1.1.1.1
Protocol/Port : icmp/0
Healthcheck detect index : 8
State : up
Destination Type/Destination Info : IP/2.2.2.2
Protocol/Port : icmp/0
Out If Index : GigabitEthernet1/0/1
Healthcheck detect index : 9
-------------------------------------------------------------------------------
https://forum.huawei.com/enterprise/en/how-to-create-ip-link/thread/462181-867
