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Footnote 1: Some of the Brocade switches use trunk commands and others use lag

commands to create the LAGs, so check the config guides for more information.

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Footnote 1: The same adjacent switch includes stackable switches.

Link Aggregation Groups are also referred to as: Ethernet trunk, NIC Teaming, Port Channel,

Port Teaming, Port Trunking, Link Bundling, EtherChannel, Multi-Link Trunking (MLT), DMLT,

SMLT, DSMLT, R-SMLT, NIC bonding, Network Fault Tolerance (NFT), and Fast EtherChannel.

Footnote 2: Multi-Chassis Trunking is technology that allows multiple switches to appear as

single logical switch connecting to another switch using a standard LAG. Since the

technology is an enhancement to the standard LAG protocol, a single MCT-unaware server or

switch using a standard LAG trunk can connect to two MCT-aware switches--and the traffic is

dynamically load balanced. For more information on this topic, please refer to the FastIron

Config Guide for the particular platform.

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In addition to enabling load sharing of traffic, LAGs provide redundant, alternate paths for

traffic if any of the segments fail.

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Footnote 1: Besides Static and Dynamic LAG, there is also the Keep Alive LAG, which is a

single connection between two switches used for gathering statistical information. It does

not provide the benefits of static or dynamic link aggregation, it is only used for advanced

statistics gathering. To create a keep alive LAG:

Syntax: [no] lag <name> keep-alive

Example: Switch(config)# lag lag1 keep-alive

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Server vendors have differing requirements and capabilities, please refer to the proper

vendor manuals for more information.

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The trunk command is used for the FastIron and ServerIron platforms, and the lag

command is used on the NetIron platform.

Please check specific product documentation for command availability.

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Some network devices support multi-chassis trunking, which takes two physical switches

and creates a single logical switch. See appendix for more information.

Footnote 1: Each port in the LAG will operate at the speed of the slowest link. For example if

one LAG is created with 2 ports and one is running at 10 Gbps and the other is running at 1

Gbps; each link will run at 1 Gbps. This behavior will occur if the ports are configured to

auto, and negotiate to different speeds.

Footnote 2: Multiple LAGs can be created on a switch with some of them being static LAGs

and some of them being dynamic LAGs. A single port can only be part of one LAG.

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Brocade code supports the IEEE 802.3ad standard for link aggregation. This standard

describes the Link Aggregation Control Protocol (LACP), a mechanism for allowing ports on

both sides of a redundant link to form a trunk (aggregate link), without the need for manual

configuration of the ports into trunk groups. When link aggregation is enabled on a group of

Brocade ports, the Brocade ports can negotiate with the ports at the remote ends of the

links to establish LAGs. Brocade ports follow the same configuration rules for dynamically

created aggregate links as they do for statically configured LAGs.

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Dynamic Link Aggregation support is disabled by default. This feature can be enabled on an individual port basis, in active or passive mode.

Active mode – When a port is enabled for active link aggregation, the port can exchange standard LACP Protocol Data Unit (LACPDU) messages to negotiate trunk group configuration with the port on the other side of the link. In addition, the active port actively sends LACPDU messages on the link to search for a link aggregation partner at the other end of the link, and can initiate an LACPDU exchange to negotiate link aggregation parameters with an appropriately configured remote port.

Passive mode – When a port is enabled for passive link aggregation, the port can exchange LACPDU messages with the port at the remote end of the link, but the passive port cannot search for a link aggregation port or initiate negotiation of an aggregated link. Thus, the port at the remote end of the link must initiate the LACPDU exchange.

System Priority (optional parameter) - The system priority parameter specifies the Brocade device’s link aggregation priority relative to the devices at the other ends of the links on which link aggregation is enabled. A higher value indicates a lower priority (range 0–65535). The default is 1.

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Port Priority - The port priority parameter determines the active and standby links. When a group of ports is negotiating with a group of ports on another device to establish a trunk group, the Brocade port with the highest priority becomes the default active port. The other ports (with lower priorities) become standby ports in the trunk group. A priority from 0 –65535 may be specified. A higher value indicates a lower priority. The default is 1.

Link Type - The link type parameter specifies whether the trunk is connecting to a server (server link) or to another networking device (switch link). The default link type is switch.

Timeout - specifies a timeout mode, which determines how fast ports are removed from a trunk.

Key - The key identifies the group of potential trunk ports this port belongs to. The code assigns a default key based on the position of the four-port group in the chassis. The code numbers the keys in ascending order beginning with key 0 for the first group of four ports. For example, an 8-port module in chassis slot 1 contains keys 0 and 1 by default. Ports 1/1 – 1/4 have key 0 and ports 1/5 – 1/8 have key 1, and so on. All ports within an aggregate link must have the same key. However, if the device has ports that are connected to two different devices, and the port groups allow the ports to form into separate aggregate links with the two devices, then each group of ports can have the same key while belonging to separate aggregate links with different devices.

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As illustrated in the diagram, on SW1, because each four-port group has a different key, ports 1 to 4 and 5 to 8 will not be in the same link aggregation group; neither will ports 1 to 4 and ports 5 to 8 on SW2.

Keys on partner devices on the opposite side do not have to match.

NOTE: In conformance with the 802.3ad specification, the default key assigned to an aggregate link is based on the port type (1 Gbps port or 10 Gbps port). The Brocade device assigns different keys to 10 Gbps ports than 1 Gbps ports, so that ports with different physical capabilities will not be able to form a trunk.

LACP message parameters include:

• Local system identifier (priority and system MAC)

• Local port identifier (priority and port number)

• Key assigned to the port

• Local state flags

Syntax: [no] link-aggregate configure [port-priority <num>] |

[key <num>]

The port-priority <num> parameter specifies an individual port’s priority within the

port group. A higher value indicates a lower priority. You can specify a priority from 0 –65535. The default is 1.

The key <num> parameter identifies the group of ports that are eligible to be aggregated

into a trunk group. The software automatically assigns a key to each group of ports. The software assigns the keys in ascending numerical order, beginning with 10000. You can change a port group’s key to a value from 10000 – 65535.

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System ID - Lists the base MAC address of the device. This is also the MAC address of port 1 (or 1/1).

Port - Lists the port number.

Sys P -Lists the System Priority configured for this port.

Port P - Lists the Port’s link aggregation Priority.

Key - Lists the link aggregation Key.

Act- (Active) Indicates the link aggregation mode which can be one of the following:

• No – The mode is passive or link aggregation is disabled (off) on the port. If link aggregation is enabled (and the mode is passive), the port can send and receive LACPDU messages to participate in negotiation of an aggregate link initiated by another port, but cannot search for a link aggregation port or initiate negotiation ofan aggregate link.

• Yes – The mode is active. The port can send and receive LACPDU messages.

Tio –(Time Out) Indicates the Time Out value of the port. The timeout value can be one of the following:

• L – Long. The trunk group has already been formed and the port is therefore using alonger message timeout for the LACPDU messages exchanged with the remote port.Typically, these messages are used as confirmation of the health of the aggregate link.

• S – Short. The port has just started the LACPDU message exchange process with the port at the other end of the link. The S timeout value also can mean that the linkaggregation information received from the remote port has expired and the ports are starting a new information exchange.

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Agg –(Aggregation) Indicates the link Aggregation state of the port. The state can be oneof the following:

• Agg – Link aggregation is enabled on the port.

• No – Link aggregation is disabled on the port.

Syn – (synchronization ) Indicates the synchronization state of the port. The state can beone of the following:

•No – The port is out of sync with the remote port. The port does not understand thestatus of the LACPDU process and is not prepared to enter a trunk link.

• Syn – The port is in sync with the remote port. The port understands the status of the LACPDU message exchange process, and therefore knows the trunk group towhich it belongs, the link aggregation state of the remote port, and so on.

Col – (collection) Indicates the collection state of the port, which determines whether theport is ready to send traffic over the trunk link.

• Col – The port is ready to send traffic over the trunk link.

• No – The port is not ready to send traffic over the trunk link.

Dis –(distribution) Indicates the Distribution state of the port, which determines whether the port is ready to receive traffic over the trunk link.

• Dis – The port is ready to receive traffic over the trunk link.

• No – The port is not ready to receive traffic over the trunk link.

Def- (default) Indicates whether port is using default link aggregation values. Defaultvalues are used if no link aggregation information is received through LACP from the port at the remote end. This field can have one of the following:

•Def – The port has received link aggregation information from the port at the other endof the link and is using the settings negotiated with that port.

• No – The port has not received link aggregation values from the port at the other endof the link and is therefore using its default link aggregation settings.

Exp –(expired) Indicates whether the negotiated link aggregation settings have expired. Thesettings expire if the port does not receive an LACPDU message from the port at theother end of the link before the message timer expires.

• Exp – The link aggregation settings this port negotiated with the port at the other endof the link have expired. The port is now using its default link aggregation settings.

• No – The link aggregation values that this port negotiated with the port at the other end of the link have not expired, so the port is still using the negotiated settings.

Ope - Operational state: This shows the operation state of the link

• Ina – Inactive

• Ope – Operational

• Blo – Port is blocked

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The rules for chassis trunking are the same as those for standalone devices.

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The following configuration steps are used to configure a LAG. Depending upon whether a

static, dynamic or keep-alive LAG is being configured. See the platform specific

Configuration Guide for more information.

Creating a Link Aggregation Group – Required for all static, dynamic or keep alive LAGs.

Adding Ports to a LAG – Required for all static, dynamic, or keep alive LAGs. A keep alive LAG

contains only one port with static and dynamic LAGs can have 2 to 32 ports.

Configuring the Primary Port for a LAG – Required for all static and dynamic LAGs. Since a

keep alive LAG contains only one port, it is unnecessary to configure this parameter.

Configuring the Load Sharing Type – Optional for all static and dynamic LAGs. Since a keep

alive LAG contains only one port, it is unnecessary to configure this parameter.

Specifying the LAG Threshold for a LAG Group – Optional for static and dynamic LAGs. Since

a keep alive LAG contains only one port, it is unnecessary to configure this parameter.

Configuring LACP Port Priority – Optional for dynamic and keep alive LAGs. Because static

LAGs do not support LACP, it is unnecessary to configure this parameter.

Configuring an LACP Timeout – Optional for dynamic and keep alive LAGs. Because static

LAGs do not support LACP, it is unnecessary to configure this parameter.

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Footnote 1: The primary port could also have been called out on the previous command line.

The trunk command is used for the FastIron and ServerIron platforms, and the lag

command is used on the NetIron platform.

Port 3/1 is used for lag configuration, so its operational state doesn’t matter.

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Footnote 1: This command is only available for the NetIron series. Hash-based is the default setting.

Per Packet Load Sharing: Per packet LAG load balancing is a type of LAG that load balances traffic on a per-packet basis, as compared to traditional server LAG load-balancing which balances traffic based on packet content such as source or destination addresses. In per packet server LAG load balancing, the packet processor (PPCR) on each module selects a port in the per packet server LAG to forward traffic in a round-robin fashion. For example, if the first port of the per packet server LAG is currently selected, the second port of the per-packet server LAG will be used next, and so on. Consequently, traffic is evenly distributed among all of the ports that are configured in a per packet server LAG. Traffic that can be forwarded out of a per-packet LAG includes L2 switching traffic, L3 routing traffic, L3VPN (2547) traffic, VLL and VPLS traffic.

Hash Based Load Sharing: shares the traffic load evenly across the ports in LAG group, while ensuring that packets in the flow are not reordered. Individual flows are assigned a LAG index to identify them. Hash based load sharing provides:

• Better Distribution

• Support for 32-port LAGs

• An increased number of fields in the packet header that can be used for load balancing

• Enhanced load sharing in configurations of ECMP with LAGs.

See the platform specific configuration guide for more information.

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Load sharing procedures differ depending on the code version the device is running.

Generally speaking, in earlier releases, the Brocade device load balances all bridged traffic

based on source and destination MAC addresses. In subsequent releases, the load

balancing method for bridged traffic varies depending on the traffic type.

Load Sharing for Unknown Unicast, Multicast, and Broadcast Traffic

The Brocade device load balances unknown unicast, multicast, and broadcast traffic based

on the source port and VLAN ID and not on any source or destination information in the

frame.

For example, when the switch receives unknown unicast, multicast, and broadcast frames,

and the frames are from the same source port, the frames are forwarded to the same port

of the trunk group. Conversely, when the switch receives unknown unicast, multicast, and

broadcast frames, and the frames are from different source ports, the frames are load-

balanced across all the ports of the trunk group. Note that this does not apply to known

unicast traffic, which is always load balanced across all the ports of a trunk group based on

the traffic's Layer 2 and Layer 3 source and destination parameters.

Check the Configuration Guide for the specific hardware/code before configuration.

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Syntax: [no] lag <name> [static | dynamic] [id <number>]

The ID parameter is optional, and the valid ID is 1 to 256. If not specified, the system will

automatically generate an ID number. Once the LAG ID is generated, it will be saved in the

configuration file along with the LAG name.

NOTE: The LAG ID parameter is for static and dynamic LAGs only. No explicit configuration of

a LAG ID is allowed on keepalive LAGs.

The static parameter specifies that the LAG with the name specified by the

<lag-name> variable will be configured as a static LAG.

The dynamic option specifies that the LAG with the name specified by the <lag-name>

variable will be configured as a dynamic LAG.

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