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Ethernet Switches & Routers

New Member
Posts: 1
Registered: ‎12-30-2011

LAG between Brocade MLX 5 and Cisco Nexus 7706

Hello, i have a problem setting up L3 LAG between Brocade MLX 5 and Cisco Nexus 7706. This is a dynamic LACP LAG with only one port in it, and it seems to form properly:


#show lag
Total number of LAGs: 1
Total number of deployed LAGs: 1
Total number of trunks created:1 (127 available)
LACP System Priority / ID: 1 / 748e.f82a.3600
LACP Long timeout: 90, default: 90
LACP Short timeout: 3, default: 3

=== LAG "L3_DC" ID 1 (dynamic Deployed) ===
LAG Configuration:
Ports: e 3/2
Port Count: 1
Primary Port: 3/2
Trunk Type: hash-based
LACP Key: 100

Port Individual Configuration:
Port Name
3/2 L3-DC-n73-et-1-6

Deployment: Trunk ID 1, Active Primary 3/2, base fid: 0x0800

Port Link Port-State Dupl Speed Trunk Tag Priori MAC Name Type
3/2 Up Forward Full 10G 1 No level0 748e.f82a.3661 L3-DC-Wroclaw-wdefault-port

Port [Sys P] [Port P] [ Key ] [Act][Tio][Agg][Syn][Col][Dis][Def][Exp][Ope]
3/2 1 1 100 Yes L Agg Syn Col Dis No No Ope


And on Nexus side:


# sh port-channel summary interface po 4
Flags: D - Down P - Up in port-channel (members)
I - Individual H - Hot-standby (LACP only)
s - Suspended r - Module-removed
S - Switched R - Routed
U - Up (port-channel)
M - Not in use. Min-links not met
Group Port- Type Protocol Member Ports
4 Po4(RU) Eth LACP Eth1/6(P) Eth2/7(D)


But when i try to ping from one side to the other, it does not work.

In ARP debug i can see that Nexus receives ARP request broadcast from MLX on Port-channel interface, and sends ARP reply back, but this reply never shows up in ARP debug on MLX's side, despite that on MLX interface, received unicast counter increases during ping attempt, so it seems that ARP reply is received, but somehow discarded on MLX' s side. What's important - when i remove LAG/etherchannel config from both sides - everything starts to work properly.






lag "L3_DC" dynamic id 1
ports ethernet 3/2
primary-port 3/2
port-name "L3-DC-n73-et-1-6" ethernet 3/2

interface ethernet 3/2
ip address



interface port-channel4

 no switchport
 ip address


interface Ethernet1/6
 no switchport
 channel-group 4 mode active
 no shutdown


I would be grateful for any hints on what can cause such behavior.



Wojtek Mitus


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