
S5720 (V200R010C00SPC600) connect to Cisco Catalist 2960 by 2 links in eth-trunk.
Configuration example - KB EKB1000435123 (for Cisco 4506) did not help to solve the issue.
Eth-trunk at Huawei – DOWN, at Cisco – UP.

Huawei S5720 diagnostic:
Cisco Catalist 2960 diagnostic:

Huawei switch config:
interface Eth-Trunk11
description Cisco2960-4-2
port link-type trunk
port trunk allow-pass vlan 3 8 21 30 to 31
stp bpdu-filter enable
stp edged-port disable
mode lacp
interface GigabitEthernet0/0/14
undo negotiation auto
description Cisco2960-4-2_1
eth-trunk 11
interface GigabitEthernet1/0/14
undo negotiation auto
description Cisco2960-4-2_2
eth-trunk 11
Cisco 2960 switch config:
interface Port-channel1
description UpSwitch
switchport trunk allowed vlan 1,3,8,21
switchport mode trunk
interface GigabitEthernet1/0/25
description UpSwitch_1
switchport trunk allowed vlan 1,3,8,21
switchport mode trunk
channel-group 1 mode on
!
interface GigabitEthernet1/0/26
description UpSwitch_2
switchport trunk allowed vlan 1,3,8,21
switchport mode trunk
channel-group 1 mode on

As LACP is used in EtherChannel, at Cisco side interfaces must be added to EtherChannel in passive mode.

Modify Cisco switch configuration of port-channel group at member-Interface view :
channel-group 1 mode on ------>>> channel-group 1 mode passive