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Link Aggregration (LAG) Management and Settings on ESW2-550X Switch

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Fri, 07/08/2016 - 13:40
Apr 26th, 2016
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Article ID: 4184

Objective

Link Aggregation Control Protocol (LACP) is a part of IEEE specification (802.3ad) that combines multiple physical ports to form a single unit called a Link Aggregate Group (LAG). Traffic load balancing on the ports in a LAG is managed by a hash-based distribution function that directs traffic based on the packet header information. LAG helps in bandwidth multiplication, increase in port flexibility and provides redundancy on links between any two devices and this helps to change the LAG speed, advertisement, flow control and also protection which can be easily identified in LAG settings table. This protocol can be used to set a single logical link between two adjacent LACP enabled devices. These two devices can have multiple physical links between them.

This document explains how to select the load balancing algorithm and to define a member or candidate port on the LAG and also how to configure LAG settings or to reactivate a suspended LAG on ESW2-550X Switches.

Applicable Devices

• ESW2-550X
• ESW2-550X-DC

Software Version

• v1.2.9.44

LAG Management

Step 1. Log in to the web configuration utility and choose Port Management > Link Aggregation > LAG Management. The LAG Management page opens.

Step 2. Click one of the following radio buttons in the Load Balance Algorithm field.

• MAC Address — Performs load balancing by source and destination MAC addresses on all the packets.

• IP/MAC Address — Performs load balancing by the source and destination IP addresses on IP packets, and by the source and destination MAC addresses on non-IP packets.

Step 3. Click the Apply button to apply the changes and the Running Configuration file is updated.

The description of the fields in the LAG Management Table are as follows.

• LAG — LAGs are shown in the column.

• Name — LAG name configured is shown in the column.

• LACP — Shows whether LACP is enabled or disabled to the particular LAG.

• Link State — Shows whether the LINK of the LAG is active or down.

• Active Member — Shows the member which are in the field and are active in the configured set.

• Standby Member —  Shows the members which are configured to the LAG members which are on standby.

Step 4. To define member or candidate port in the LAG Management Table section, click the radio button of the desired LAG to be configured and click Edit. The Edit LAG Membership page opens.

Step 5. Choose the LAG number from the LAG drop-down list.

Step 6. Enter a name for the LAG in the LAG Name field.

Step 7. Check the Enable check box in the LACP field. This makes it a dynamic LAG. Static LAG is a bunch of links aggregated where there is no signaling between the two peers and therefore a misconfiguration on one side may lead to harmful effects such as Links Mismatch. Dynamic LAG uses LACP packets to establish connection between the two peers. 

Note: At least one side of the peer needs to be configured in Dynamic LAG.

Step 8. Choose the desired unit or slot from the Unit/Slot drop-down list. The unit identifies the switch whether it is a master or slave in the stack, unit 1 is master and unit 2 is slave. The slot identifies whether the switch is ESW2-550 or ESW2-550X, slot 1 is ESW2-550 and slot 2 is ESW2-550X.

Step 9. To move the ports that are to be assigned to the LAG, click the port in the Port List and click the > button. Up to eight ports to a static LAG and 16 ports to a dynamic LAG can be assigned. In the above image, LACP has been configured so it is a Dynamic LAG configuration.

Step 10. Click Apply. The changes are displayed in the LAG Management Table.

LAG Settings Configuration

Step 1. Log in to the web configuration utility and choose Port Management > Link Aggregation > LAG Settings.The LAG Settings page opens.

Step 2. Click the radio button for LAG that needs to be modified and then click Edit

Step 3. The Edit LAG Settings page opens.

Step 4. (Optional) Choose the desired LAG that you want to edit from the LAG drop-down list.

Step 5. Enter the LAG name or a comment in the LAG Description field.

LAG Type field displays the port type that comprises the LAG.

Step 6. Click the desired radio button if you want the selected LAG to be Up or Down in the Administrative Status field. Up means the link is active, and down means the link is not active.

Step 7. Check the Reactivate Suspended LAG check box to reactivate a port if the LAG has been disabled through the locked port security option or through ACL configurations.

Operational Status field displays whether the LAG is currently operating.

Step 8. Check the Administrative Auto Negotiation check box to enable or disable auto-negotiation on the LAG. Auto-negotiation is a protocol between two link partners that enables a LAG to advertise its transmission speed and flow control to its partner (the Flow Control default is disabled).

Note: It is recommended to keep auto-negotiation enabled on both sides of an aggregate link, or disabled on both sides, while ensuring that link speeds are identical.

Operational Auto Negotiation field displays the auto-negotiation setting.

Step 9. Click the desired radio button in the Administrative Speed field. The available speeds are: 10M, 100M and 1000M.

Note: When auto negotiation is enabled, by default 10M is selected.

Operational LAG Speed field displays the current speed at which the LAG is operating.

Step 10. Check the desired Administrative Advertisement check box to be advertised by the LAG. The options are:

• Max Capability — All LAG speeds and both Full duplex and half duplex modes are available. Full duplex means that the interface supports transmission between the device and its link partner in both directions simultaneously. Half duplex means that the interface supports transmission between the device and the client in only one direction at a time.

• 10 Full — The LAG advertises a 10 Mbps speed and the mode is full duplex.

• 100 Full — The LAG advertises a 100 Mbps speed and the mode is full duplex.

• 1000 Full — The LAG advertises a 1000 Mbps speed and the mode is full duplex.

Operational Advertisement field displays the Administrative Advertisement status. The LAG advertises its capabilities to its neighbor LAG to start the negotiation process. The possible values are those specified in the Administrative Advertisement field.

Step 11. Click the desired radio button in the Administrative Flow Control field. Flow control should be enabled to control network traffic during periods of congestion and prevent the loss of packets when port buffer thresholds are exceeded. Click Enable, Disable or Auto-Negotiation of Flow Control on the LAG.

• Enable — This option allows the switch to advertise the 802.3x format frames.

• Disable — This option to disables flow control.

• Auto-Negotiation — Enables Auto Negotiation on the port. Auto Negotiation is a protocol between two link partners that enables a port to advertise its transmission rate, duplex mode and flow control abilities to its partner.

The Operational Flow Control field displays the current Flow Control setting.

Step 12. Check the Protected LAG check box to make the LAG a protected port for Layer 2 isolation. See the Port Configuration description in the Setting Basic Port Configuration section for details regarding protected ports and LAG's.

Step 13. Click Apply. The changes are displayed in the LAG Settings Table.

Step 5. (Optional) Click Copy Settings... to copy the settings of a LAG to another LAG member. The Copy Settings page opens:

Step 6. Enter the LAG number value to which the configuration is copied into the field:

Step 7. Click Apply. The changes are displayed in the LAG Settings Table.

LACP Configuration

Step 1. Choose Port Management > Link Aggregation > LACP from the web configuration utility. The LACP page opens:

Note: LACP System Priority is different from LACP Port priority but LACP system priority and LACP port priority are both used to determine which of the candidate ports become active member ports in a dynamic LAG configured with more than eight candidate ports. LACP port priority decides which interface is used for LACP transmission and LACP system priority decides which links between the LACP are active.

Step 2. Enter the LACP system priority value in the LACP System Priority. The device with lowest system priority value controls candidate port selection to the LAG. If both the priorities are same then the MAC address of the local and remote device are compared and lowest MAC address controls candidate port selection to the LAG.

Step 3. Click Apply.

Step 4. Choose the desired interface from the Filter: Interface Type equals to drop-down list.

Step 5. Click the radio button that corresponds to the desired interface to edit and then click the Edit button. The Edit LACP window opens.

Step 6. Choose the appropriate interface from the Unit/Slot and port number from the Port drop-downlist for which the port priority and timeout values are to be set.

Step 7. Enter the LACP port priority value for the particular port in the LACP Port Priority field. Port with lowest priority is more likely to be in the active stand than the high priority one.

Step 8. Click the desired radio button in the LACP Timeout field to set whether the interval between retransmissions is long or short. Long time out would be 90 seconds and short time out will be 3 seconds by default.

Step 9. Click Apply. The changes are displayed in the LACP Settings Table.

Step 10. (Optional) Click Copy Settings... to copy the settings of a port interface to another Port interface. The Copy Settings page opens:

Step 11. Enter the Port number to which the configuration is copied in the to: field.

Step 12. Click Apply. The changes are displayed in the LACP Interface Table.

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