Chapter 6: Link Aggregation

Table Of Contents

Link Aggregation - ONS 15305

6.1  View Link Aggregation

6.1.1  Modify Link Aggregation

6.1.2  Trunk Elements used by Management are Named ifindex

Link Aggregation - ONS 15305

The purpose of this section is to describe the tasks involved when managing the link aggregation functionality of the network element. Link aggregation is also called Trunking.

Link aggregation is used to optimize port (link) usage by grouping ports together to form a single aggregate. Link aggregation multiplies the bandwidth between the devices, increases port flexibility and provides link redundancy.

The network element defines the number of link aggregations and a maximal number of ports in each link aggregation.

6.1  View Link Aggregation

You can view specific object properties in the attributes pane:

Step 1 Select the device > Link Aggregation object in the topology pane to view the specific object properties in the attributes pane, Figure 6-1.

Figure 6-1 Attributes related to Link Aggregation

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6.1.1  Modify Link Aggregation

You can modify the modifiable Link Aggregation parameters, and this involves:

•Modification of attributes for an aggregation.

•MAC address type for an aggregation.

•Balancing attributes for an aggregation.

•Adding of new port(s) to an aggregation.

•Deletion of port(s) in an existing aggregation.

The link aggregation feature, also known as trunking, allows you to link a group of ports together to form a single trunk (aggregated group). Link aggregation can be used to increase bandwidth between devices and/or to provide link redundancy.

The link aggregation feature has a number of limitations:

•Only LAN and WAN ports can be part of a trunk.

•Maximum 8 trunks can be defined on the network element.

•Maximum 8 ports can be grouped within a single trunk.

Note 8 possible trunks are already created, but they include no port. The trunks are listed under the attribute Device > LinkAggregation > LinkAggregationList. Each trunk is identified by its ifIndex (from 65 to 72).

The number of trunks configured simultaneously is limited by equipped module type(s). Notice the following:

•Modules equipped with < 8 Ethernet LAN- and/or WAN-ports support one link aggregation trunk each.

•Modules equipped with 9-16 Ethernet LAN- and/or WAN-ports support two link aggregation trunks each, though limited within groups of bridge port numbers for configuration. Table below shows valid configurations for link aggregation using modules with 16 FE ports (FE = WAN- and/or LAN-ports).

Table 6-1 Valid Link Aggregation configuration for 16xFE port module

Slot

Trunk

Valid groups of bridge port numbers

1

1

1-8

1

2

9-16

2

1

17-24

2

2

25-32

3

1

33-40

3

2

41-48

4

1

49-56

4

2

57-64

In order to assign a port to a trunk, the port must comply with the following requirements:

•A layer 3 interface is not configured on the port.

•A VLAN is not configured on the port.

•The port is not assigned to a different trunk.

•An available MAC address exists which can be assigned to the port.

•Auto-negotiation mode is not configured on the port.

•The port is in full-duplex mode.

•All ports in a trunk must operate at the same rate.

•All ports in a trunk must have the same ingress filtering and tagged modes.

•All ports in a trunk must have the same back pressure and flow control modes.

•All ports in a trunk must have the same priority.

•All ports in a trunk must have the same transceiver type.

•All ports in a trunk must belong to the same module, that means they must be located on the same slot.

6.1.1.1  Assigning a Port to a Trunk

To assign a port to a trunk:

Step 1 Make sure that the port to be added to a trunk complies with the requirements listed above.

Step 2 Click on the ONS 15305 managed object, and then on the device managed object in the topology browser.

Step 3 Click on the linkAggregation attribute in the attribute window.

Step 4 Click on the linkAggregationPort attribute in the attribute window.

Step 5 Identify the port to add via its ifIndex listed under the portIfIndex attribute.

Step 6 Verify that the port can be part of a trunk by checking the aggregated attribute. If aggregated displays true, the port can be included in a trunk, go to the next step. If aggregated displays false, the port can only operate as an individual link, and cannot be part of a trunk. Select another port (go back to Step 5).

Step 7 Edit the actorAdminKey attribute. This attribute must be set to the ifIndex of the trunk to which the port shall be assigned. Legal values are [65:72].

Note To find out the ifIndex used by the trunk, check the Device > LinkAggregation > LinkAggregationList attribute

Step 8 Click Save.

6.1.2  Trunk Elements used by Management are Named ifindex

Regular ports, LAN and WAN, have ifIndexes from 1 to 64, depending on the slot and port number.

16 ifIndexes are reserved for each slot, although none of today's modules use more than 8. For example, a fast Ethernet (FE) module with 8 ports located in slot 3, have ifindex range from 33 for port 3/1 to 40 for port 3/8.

STM-1 modules are special since they are a combination of 8 SDH ports and 8 WAN ports. WAN ports in an 8XSTM1 module are numbered x/9 to x/16 (x is the slot), while the ifIndexes corresponds
to x/1to x/8. For an 8xSTM-1 module located in slot 2, the ifindex range is 17 to 24(17 for port 2/9, 24 for port 2/16). Giga bit Ethernet (GE) ports use the first ifIndexes for the particular slot. For example, a 2XGE in slot 4 have ifindex numbers 49 for port 4/1 and 50 for port 4/2.

Maximum number of trunks in the system is 8, and the trunk ifindex range is 65 to 72. The trunk ifindex is used as port number when a trunk is assigned to a VLAN.

An example to illustrate the creation of a trunk and adding the trunk to a VLAN, Figure 6-2.

The first two WAN ports of slot 1 are used to create a trunk with ifindex 65.

Figure 6-2 Creating and Editing a trunk to a VLAN

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The trunk and the second GE port in slot 2 are put together in a VLAN, Figure 6-3.

Figure 6-3 VLAN settings for a Trunk with GE