Creating and Managing Multichassis Link Aggregation Groups (MC-LAGs)
Multichassis link aggregation groups (MC-LAGs) enable a device to form a logical link aggregation group (LAG) interface between two switches. An MC-LAG provides redundancy and load balancing between the two switches, multihoming support, and a loop-free Layer 2 network without running Spanning Tree Protocol (STP).
MC-LAG peer switches use the Inter-Chassis Control Protocol (ICCP) to exchange control information and interchassis link (ICL) to exchange data.
At one end of an MC-LAG are the MC-LAG client devices, such as servers or switches, that have one or more physical links in a LAG. Client devices do not need to detect the MC-LAG. At the other end of the MC-LAG are two peer devices. Each of these switches has one or more physical links connected to a single client device. The switches coordinate with each other to ensure that data traffic is forwarded properly.
You can create MC-LAGs using QFX Series and EX9200 devices. However, both the peer devices must be the same type . Network Director can manage MC-LAG devices that are created and configured through the CLI mode also. If MC-LAG devices are configured through the CLI mode, ensure that LLDP is enabled on MC-LAG, ICCP LAG, ICL LAG, and client LAG links.
Supported devices in an MC-LAG:
Peer devices: QFX5100, QFX10002, and EX9200 switches
Client devices: All standalone and Virtual Chassis devices managed by Network Director except IP Fabric devices and MX Series devices
For detailed steps on creating MC-LAGs using Network Director, follow the procedure given below or the steps shown in this video-based tutorial:
This topic includes:
Accessing the MC-LAG Page
To access the MC-LAG page:
Creating an MC-LAG
To create an MC-LAG:
Click Create MC-LAG in the Manage MC-LAG page.
The Create MC-LAG page opens. It displays two tabs—Peer Devices and Client Devices. By default, the Peer Devices tab is selected and displays in orange color.
On the left of the Create MC-LAG page, the Peer Devices tab lists QFX Series and EX9200 devices that are managed by Network Director. These are the available devices from which you can select the peer devices for the MC-LAG you create. On the right, a schematic diagram of the two peer devices PEER␣1, PEER␣2, and a representation of the client devices as boxes are displayed.
Creating an MC-LAG involves four tasks:
- Selecting Peer Devices and Configuring Peer-to-Peer Link Settings
- Selecting Client Devices and Configuring Client-to-Peer Link Settings
- Saving MC-LAG Settings
- Deploying MC-LAG Configuration
Selecting Peer Devices and Configuring Peer-to-Peer Link Settings
To select the peer devices and configure peer-to-peer link settings:
Selecting Client Devices and Configuring Client-to-Peer Link Settings
To select a client device and configure client-to-peer link settings:
Saving MC-LAG Settings
To save the MC-LAG settings that you configured:
Deploying MC-LAG Configuration
To deploy a new or edited MC-LAG configuration:
MC-LAG Automation Parameters
Network Director configures a number of parameters internally and automates the creation or modification of MC-LAGs.
Table 1 describes the parameters that are internally configured by Network Director.
Parameter |
Description |
---|---|
LAG |
LAG is created for ICCP, ICL, and MC-AE in peer devices, and a LAG is created for client devices. |
mc-ae-id |
Specifies which MC-LAG the aggregated Ethernet interface belongs to. |
redundancy-group (supported only in QFX10002 and EX9200 devices) |
Used by ICCP to associate multiple chassis that perform similar redundancy functions. It is used to establish a communication channel so that applications running on the peer devices can exchange messages. |
init-delay-time:240ms: |
Specifies the delay in number of seconds to bring the MC-LAG interface back to the Up state when an MC-LAG peer is rebooted. |
chassis-id 0 for Peer 1, and 1 for Peer 2 |
Used by LACP for calculating the port number of the MC-LAG physical member links. Each MC-LAG peer must have a unique chassis ID. |
status-control Active for Peer 1, and Standby for Peer 2 |
Specifies whether this node becomes active or goes into standby mode when an ICL failure occurs; must be active on one node and standby on the other node. |
LACP active |
Configured in ICL LAG, ICCP LAG, MC-LAG and client switch LAG. LACP is used to discover multiple links from a client device connected to an MC-LAG peer. LACP must be configured on all member links for an MC-LAG to work correctly. |
LACP system-id and admin-key |
Configures the same LACP system ID and admin-key for the MC-LAG on each MC-LAG peer. This displays Peer␣1 and Peer␣2 as a single switch to the edge switch when negotiating LACP. |
LACP periodic fast |
Configured on ICCP LAG, ICL LAG and MC-LAG. LACP fast periodic is achieved by configuring fast intervals (in seconds) for periodic transmission of LACP. |
Hold time Up 100000 down 0 for interfaces used for MC LAG. Up 0 down 2000 for interfaces used for ICL LAG. |
Specifies the hold-time value to use to damp interface transitions. When an interface goes down, it is not broadcast to the rest of the system till it remains down for the hold-time period. Similarly, an interface is not broadcast as being Up till it remains up for the hold-time period. |
multi-chassis-protection |
Specifies the peer’s ICCP IP address and the ICL link used for protection if the MC-AE interface goes down. |
session-establishment-hold-time 300 |
Establishes ICCP connection quickly. |
backup-liveness-detection: management IP of peer device |
Is invoked when the ICCP link goes down. With backup liveness detection enabled, the MC-LAG peers establish an out-of-band channel through the management network in addition to the ICCP channel. |
liveness-detection minimum-receive-interval 500, multiplier 3, transmit-interval 500 |
Determines whether a peer is up or down by exchanging keepalive messages over the management link between the two ICCP peers. |
RSTP |
Is enabled on peer devices MC-LAG and switch client
LAG in point to point mode . If client is a server, then it enables |
ARP, MAC, arp-l2-validate, l2-interface ICL LAG on IRB |
Provides IRB-to-IRB connectivity across the ICL. Using the VRRP over IRB method to enable Layer 3 functionality, it configures static ARP entries through the ICL for the IRB interface of the remote MC-LAG peer, which enables routing protocols to run over the IRB interfaces. |
Editing an MC-LAG
In the Manage MC-LAG page, you can add, edit or delete peer ports, edit existing peer-to-peer link settings, add client, remove client, and edit client-to-peer link settings. You cannot add or delete peer devices if both the peers are part of MC-LAG.
Click Edit corresponding to the MC-LAG peers that you want to modify, in the Manage MC-LAG page.
The Edit MC-LAG page opens. It displays two tabs—Peer Devices and Client Devices. If both the peer devices of the MC-LAG are already configured as part of the MC-LAG, the Client Devices tab is selected, and it displays in orange color. On the left of the Edit MC-LAG page, a list of client devices are displayed.
If one of the peer devices is Unknown, the Peer Devices tab is selected, and it displays in orange color. On the left of the Edit MC-LAG page, a list of peer devices, that are of the same type and ELS capability as of the discovered peer, are displayed.
On the right of the Edit MC-LAG page, a schematic diagram of the existing two peer devices PEER␣1, PEER␣2, and a representation of the client devices as boxes are displayed.
- Managing Peer Devices and Peer-to-Peer Link Settings
- Managing Client Devices and Client-to-Peer Link Settings
Managing Peer Devices and Peer-to-Peer Link Settings
To add, edit, or delete a peer port, or edit peer-to-peer link settings:
Managing Client Devices and Client-to-Peer Link Settings
To add or remove client devices, and edit client-to-peer link settings:
Deleting an MC-LAG
To delete MC-LAG:
Managing an MC-LAG Created Through CLI Mode
- MC-LAG Peer Pairing
- Mapping Client Devices to Peer Devices
- Ports Mapping Between Peer-to-Peer and Client-to-Peer Devices
MC-LAG Peer Pairing
Once the MC-LAG devices are discovered by Network Director and Network Director successfully retrieves the MC-LAG configuration from the peer devices, Network Director pairs the MC-LAG peers based on the ICCP local IP address and peer IP address. For example, if Peer␣1 is configured with ICCP local IP address 192.0.2.1 and Peer IP address 192.0.2.2, and Peer 2 is configured with ICCP local IP address 192.0.2.2 and Peer IP address 192.0.2.1, then based on the local IP address of Peer␣1, Network Director searches for devices that have the same peer IP address as the local IP address. Because Peer 2 has the same peer IP address as the Peer␣1 IP address, these two devices form MC-LAG peers. If in case, the local IP address is not found, then Network Director displays one of the peer devices in the MC-LAG pair as Unknown in the MC-LAG Manage page.
Mapping Client Devices to Peer Devices
If LLDP is enabled in the connected ports of the peer devices
and client devices, after refreshing the topology, the Edit MC-LAG
page displays the Network Director managed client switches connected
to peer devices. If the client device is not managed by Network Director,
or if the client device is not a switch (it is a bare metal server
or a hypervisor), or if the topology information is not available
for the devices, then the Edit MC-LAG page displays the client device
as Client_MC-AE ID (Unknown)
, where MC-AE ID specifies which MC-LAG the aggregated Ethernet port
belongs to.
Ports Mapping Between Peer-to-Peer and Client-to-Peer Devices
On refreshing the topology, peer-to-peer link settings display the port mapping between the peer devices, and client-to-peer link settings display the port mapping between the client and peer devices.