Configure Eth-Trunk Protection for the Link Between VRRP Devices
In a VRRP scenario, if inter-interface backup (only one interface forwards traffic in normal cases) is used for the upstream gateway of access devices and the interface that forwards traffic fails, the backup interface starts to forward traffic. If heartbeat packets are lost between VRRP devices, two master VRRP devices appear. As a result, traffic on the access devices may be interrupted.
Scenario
On the network shown in Figure 1-5, inter-interface backup is used for the UMG's GE 1/0/0 and GE 1/0/1. Only one interface is enabled to forward traffic. VRRP is deployed on Device A and Device B, and Eth-Trunk protection is configured for the link between the devices.
Configuration Requirements
A VRRP backup group must be configured on Device A and Device B. A high priority is set for Device A so that Device A functions as the master device. A low priority is set for Device B so that Device B functions as the backup device.
An Eth-Trunk interface must be configured on both Device A and Device B. Ethernet physical interfaces on different boards are added to the Eth-Trunk interface to ensure that the Eth-Trunk still has an Up link after a board fails.
Misconfiguration Risks
Risk description:
There is a high probability that services on the UMG are interrupted if the heartbeat link of the Eth-Trunk interface's member interface fails and the following conditions are met:
The UMG's interfaces support only inter-interface backup. That is, only one interface is Up.
The interfaces of the heartbeat link between Device A and Device B do not use the inter-board trunk mode.
Identification method:
NOTE:The display interface eth-trunk command must be run on both Device A and Device B to check whether inter-board member interfaces exist.
Check whether the Eth-Trunk interface's member interfaces are inter-board member interfaces.
<HUAWEI> display interface eth-trunk 1
Eth-Trunk1 current state : UP Line protocol current state : UP Link quality grade : GOOD Description:HUAWEI, Eth-Trunk1 Interface Switch Port, TPID : 8100(Hex), Hash arithmetic : According to flow,Maximal BW: 2G, Current BW: 1G, The Maximum Transmit Unit is 1500 IP Sending Frames' Format is PKTFMT_ETHNT_2, Hardware address is 0018-82d9-e71b Physical is ETH_TRUNK Current system time: 2017-04-11 04:15 Last 300 seconds input rate 0 bits/sec, 0 packets/sec Last 300 seconds output rate 0 bits/sec, 0 packets/sec Realtime 2 seconds input rate 0 bits/sec, 0 packets/sec Realtime 2 seconds output rate 0 bits/sec, 0 packets/sec Input: 3 packets,939 bytes 0 unicast,0 broadcast,3 multicast 0 errors,0 drops Output:3 packets,917 bytes 0 unicast,0 broadcast,3 multicast 0 errors,0 drops Input bandwidth utilization : 0% Output bandwidth utilization : 0% ----------------------------------------------------- PortName Status Weight ----------------------------------------------------- GigabitEthernet1/1/8 DOWN 1 GigabitEthernet3/1/0 UP 1 ----------------------------------------------------- The Number of Ports in Trunk : 2 The Number of UP Ports in Trunk : 1If the Eth-Trunk interface has multiple member interfaces and the member interfaces are located on different boards (for example, GE 1/1/8 and GE 3/1/0 are located on the boards in slots 1 and 3, respectively), the risk does not exist. If the member interfaces are located on the same board, the risk exists.
Recovery measures:
Configure an Eth-Trunk interface on both Device A and Device B. Add Ethernet physical interfaces on different boards to the Eth-Trunk interface to ensure that the Eth-Trunk still has an Up link after a board fails.
