This post is to list out the compatible configuration to allow default VLAN1 traffic between Cisco and Juniper. In this post, let’s assume VLAN1 are used for Switch Management, yes it is bad practice 🙁
Single Connection Between Cisco and Juniper
Cisco
interface GigabitEthernet1/0/14
description ***Single_conneciton_between_Cisco_Juniper****
switchport mode trunk
interface Vlan1
ip address 10.0.0.1 255.255.255.0
ICTFellaCiscoSW01#show interfaces trunk
Port Mode Encapsulation Status Native vlan
Gi1/0/14 on 802.1q trunking 1
Port Vlans allowed on trunk
Gi1/0/14 1-4094
Port Vlans allowed and active in management domain
Gi1/0/14 1,3-8,10,15,20,30,40,50-52,75,80,99,131,133,191-192,201-206,212-213,223,500-501,503,701
Port Vlans in spanning tree forwarding state and not pruned
Gi1/0/14 1,3-8,10,15,20,30,40,50-52,75,80,99,131,133,191-192,201-206,212-213,223,500-501,503,701
Juniper
Please define your VLAN 1 as native vlan on the Juniper side:
admin@ICTFellaJuniperSW01# show interfaces | match ge-0/0/13 | display set
set interfaces ge-0/0/13 description Cisco_Juniper_trunk
set interfaces ge-0/0/13 native-vlan-id 1
set interfaces ge-0/0/13 unit 0 family ethernet-switching interface-mode trunk
set interfaces ge-0/0/13 unit 0 family ethernet-switching vlan members all
set interfaces ge-0/0/13 unit 0 family ethernet-switching storm-control default
admin@ICTFellaJuniperSW01# show interfaces irb | display set
set interfaces irb unit 0 family inet address 10.0.0.234/24
{master:0}[edit]
admin@ICTFellaJuniperSW01# show vlans | display set
set vlans default vlan-id 1
set vlans default l3-interface irb.0
LACP between Cisco and Juniper
Cisco
interface TenGigabitEthernet1/1/4
description LACP_Cisco_Juniper
switchport mode trunk
switchport nonegotiate
channel-protocol lacp
channel-group 44 mode active
interface TenGigabitEthernet2/1/4
description LACP_Cisco_Juniper
switchport mode trunk
switchport nonegotiate
channel-protocol lacp
channel-group 44 mode active
interface Port-channel44
description LACP_Cisco_Juniper
switchport mode trunk
switchport nonegotiate
interface Vlan1
ip address 10.0.0.1 255.255.255.0
Juniper
Important Note: Please make sure the Device Count for Aggregated Devices are set, otherwise LACP will never work
set chassis aggregated-devices ethernet device-count 64
set interfaces ge-0/1/2 ether-options 802.3ad ae44
set interfaces ge-1/1/2 ether-options 802.3ad ae44
set interfaces ae44 description ***LACP_Cisco_Juniper***
set interfaces ae44 native-vlan-id 1
set interfaces ae44 aggregated-ether-options lacp active
set interfaces ae44 aggregated-ether-options lacp periodic fast
set interfaces ae44 unit 0 family ethernet-switching interface-mode trunk
set interfaces ae44 unit 0 family ethernet-switching vlan members all
admin@ICTFellaJuniperSW01# show interfaces irb | display set
set interfaces irb unit 0 family inet address 10.0.0.234/24
{master:0}[edit]
admin@ICTFellaJuniperSW01# show vlans | display set
set vlans default vlan-id 1
set vlans default l3-interface irb.0
Useful link
https://www.cisco.com/c/en/us/td/docs/ios/12_2sb/feature/guide/gigeth.html