Link Aggregation — Port Trunking

Sub-topics:

Link Aggregation — Global Configuration

Link Aggregation Trunk Table

Link Aggregation Port Table

Link aggregation, also known as port trunking, is a method of increasing bandwidth by combining physical network links into a single logical link. Link aggregation increases the capacity and availability of the communications channel between devices (both switches and end stations) by using Fast Ethernet and Gigabit Ethernet technology.

Multiple parallel physical links between two devices can be grouped together to form a single logical link. Link aggregation also provides load balancing where processing and communications activities are distributed across several links in a trunk. This prevents single link overloading.

Treating multiple LAN connections as one aggregated link offers the following advantages:

Higher link availability.

Increased link capacity.

Improvements in existing hardware. Upgrading to higher-capacity link technology is not necessary.

LinkProof supports port trunking according to the IEEE 802.3ad standard for link aggregation.

According to the IEEE 802.3ad standard:

Link aggregation is supported only on links using the IEEE 802.3 MAC.

Link aggregation is supported only on point-to-point links.

Link aggregation is supported only on links operating in full duplex mode.

Aggregation is permitted only among links with same speed and direction. On the LinkProof device, bandwidth increments are provided in units of 100 Mbit/s and 1 Gbit/s respectively.

Traffic from the same MAC client may be distributed across multiple links. To guarantee correct ordering of frames at the receiving-end station, all frames belonging to one conversation must be transmitted through the same physical link. The algorithm for assigning frames to a conversation depends on the application environment. LinkProof can define conversations using Layer 2, 3, or 4 information or a combination of layers (Layer 3 and 4 for example).

The failure or replacement of a single link within a Link Aggregation Group will not cause failure from the perspective of the client’s MAC address.

The LinkProof Link Aggregation feature allows defining up to seven trunks. Up to eight physical links can be aggregated into one trunk. All trunk configurations are static.

To provide optimal distribution for different scenarios the load sharing algorithm allows decisions based on source or destination (or both) L2 address (MAC), L3 address (IP), and L4 address (TCP/UDP port numbers). These parameters are used as input for a hashing function.

Notes

>>	A port belonging to a trunk should not be copied to another port.

>>	A trunk cannot be mirrored.

>>	Ports that are part of a trunk cannot be used in port rules. The entire trunk, however, can be used in port rules.

>>	Radware recommends that you configure Link Aggregation using CLI. For more information, see the user guide.

>>	When choosing the Link Aggregation configuration using Web Based Management, it important for the administrator to choose the valid Link Aggregation configuration from Table 49 - Supported Link-Aggregation Configurations for OnDemand Switch 2, page 108.

 

The following table lists combinations for link aggregation supported on the OnDemand Switch 2 platform.

 

Table 49: Supported Link-Aggregation Configurations for OnDemand Switch 2

Layer	1	2	3	4	5	6	7	8	9
2	Source MAC	Destination MAC	Both	Ignore	Ignore	Ignore	Ignore	Ignore	Ignore
3	Ignore	Ignore	Ignore	Source IP	Destination IP	Both	Source IP	Destination IP	Both
4	Ignore	Ignore	Ignore	Ignore	Ignore	Ignore	Source Port	Destination Port	Both

Note	On OnDemand Switch VL platforms, combinations for link aggregation are not limited.