Dynamic Aggregator Configuration

The Dynamic Aggregator feature will enable ports to choose their aggregator dynamically based on their partner information. When two ports are connected to a same partner and their LAGG ID (System ID + Admin key) information is identical, they will form a single aggregation. Otherwise, the ports will belong to different aggregators.

For a port to participate in this dynamic selection, it has to be configured as a “default” port of an aggregator. Only one default port can be configured for an aggregator. When a default port is configured for an aggregator, no other port can be configured to be a member of that aggregator. The port will belong to the default aggregator when it is connected to a unique partner or when no partner information is available.

Consider the following scenario where four aggregators are created and each has been assigned a default port.

Figure 1. Initial Scenario


All ports should be configured with the same Actor Admin key.

After the LACP PDUs are exchanged, selection logic is triggered to choose the aggregator based on the Partner information. The following parameters are compared for a port to belong to the same aggregator.
  • Actor System ID (MAC address + Priority)
  • Actor Admin Key
  • Partner System ID (MAC Address + Priority)
  • Partner Admin Key
Figure 2. Port Reallocation across Aggregator at end of Selection Logic


When two or more ports are connected to the same partner (these ports have same LAG-ID), then the lowest numbered aggregator associated with the set of ports will be chosen and all ports will be attached to that aggregator. The default port of the least aggregator is referred to as the “primary” port. Ports 1, 2, and 3 are connected to the same partner and Port 4 is connected to a different partner. Therefore, Ports 2 and 3 move out of their default aggregator and get attached to Agg-2.

Figure 3. Primary Port is down


When the primary port in aggregator goes down, the associated aggregator will also go down and the rest of the ports in the aggregator will move to next least numbered aggregator.

When a port moves to a different aggregator, the port will inherit all aggregator’s properties to which they are bound.

The port specific attributes, such as Actor Admin state, Partner Admin state, and Actor admin port will remain same even if the port moves to a new aggregator. VLAN/STP properties will be inherited from the new aggregator to which the ports get bound.

Parent topic: LA Configuration

Configuration

This section describes the configuration for creating an aggregator and binding a port to an aggregator.

The following configuration creates po25 and binds Port-3 to po25 with aAggPortActorAdminKey = 25 and aAggActorAdminKey = 25

  1. Execute the following commands.
    iS5comm# configure terminal
    iS5comm(config)# set port-channel enable
    iS5comm(config)# interface port-channel 25
    iS5comm(config-if)# no shutdown
    iS5comm(config-if)# exit
    iS5comm(config)# interface gigabitethernet 0/3
    iS5comm(config-if)# no negotiation
    iS5comm(config-if)# duplex full
    iS5comm(config-if)# channel-group 25 mode active
    iS5comm(config-if)# end
  2. View the information using the following command
    iS5comm# show etherchannel detail
    Port-channel Module Admin Status is enabled
    Port-channel Module Oper Status is enabled
    Port-channel recovery action on exceeding Threshold is None
    Port-channel Independent mode is disabled
    Port-channel System Identifier is  00:55:44:33:22:11
    LACP System Priority: 20
    LACP Error Recovery Time: 0
    LACP Error Recovery Threshold: 5
    LACP Recovery Triggered count: 0
    LACP Error Recovery Threshold for Defaulted State : 5
    LACP Error Recovery Threshold for Hardware Failure : 5
    LACP Same state threshold : 5
                     Channel Group Listing
    ---------------------
    Group: 1
    ----------
    Protocol :LACP
                     Ports in the Group
    ------------------
    

    Port : Gi0/1
    

    -------------
    

    

    Port State = Down, Not in Bundle
    

    Reason for port-down : Oper status of the port is down
    

    Channel Group : 1
    

    Mode : Active
    

    Port-channel = Null
    

    Pseudo port-channel = Po1
    

    LACP port-priority  = 128
    

    LACP Wait-time  = 2 secs
    

    LACP Port Identifier = 1
    

    LACP Activity : Active
    

    LACP Timeout : Long
    

    LACP Error State : None
    

    

    Aggregation State : Aggregation, Defaulted
    

    

    Port : Gi0/2
    

    -------------
    

    

    Port State = Down, Not in Bundle
    

    Reason for port-down : Oper status of the port is down
    

    Channel Group : 1
    

    Mode : Active
    

    Port-channel = Null
    

    Pseudo port-channel = Po1
    

    LACP port-priority  = 128
    

    LACP Wait-time  = 2 secs
    

    LACP Port Identifier = 2
    

    LACP Activity : Active
    

    LACP Timeout : Long
    

    LACP Error State : None
    

    

    Aggregation State : Aggregation, Defaulted
    

    

    

    Port : Gi0/24
    

    -------------
    

    

    Port State = Up in Bundle
    

    Channel Group : 1
    

    Mode : Active
    

    Port-channel = Po1
    

    Pseudo port-channel = Po1
    

    LACP port-priority  = 20
    

    LACP Wait-time  = 1 secs
    

    LACP Port Identifier = 1
    

    LACP Activity : Active
    

    LACP Timeout : Short
    

    LACP Error State : None
    

    

    Aggregation State : Aggregation, Sync, Collecting, Distributing, Defaulted
    

                     LACP Port   Admin  Oper   Port    Port
    

    Port     State   Priority    Key    Key    Number  State
    

    ---------------------------------------------------------------------
    

    Gi0/1    Down    128         1      1      0x1     0xa2
    

    Gi0/2    Down    128         1      1      0x2     0xa2
    

    Gi0/24   Bundle  20          1      1      0x18    0xfe
    

    

    Port-channel : Po1
    

    -------------------
    

    

    Number of Ports = 3
    

    HotStandBy port = null
    

    Port state = Port-channel Ag-Inuse
    

    Protocol = LACP
    

    Aggregator-MAC  e8:e8:75:90:5f:9d
    

    Maximum number of Ports  = 8
    

    

    Port-Channel Mtu         = 1500
    

    Port-Channel Speed       = 1000 Mbps
    

    Port-Channel High Speed  = 1000 Mbps
    

    Port-Channel Member Ports Speed = 1000 Mbps
    

    Port-Channel Member Ports High Speed  = 1000 Mbps
    

    

    

                     Channel Group Listing
    

    ---------------------
    

    Group: 25
    

    ----------
    

    Protocol :LACP
    

    

                     Ports in the Group
    

    ------------------
    

    

    Port : Gi0/3
    

    -------------
    

    

    Port State = Down, Not in Bundle
    

    Reason for port-down : Oper status of the port is down
    

    Channel Group : 25
    

    Mode : Active
    

    Port-channel = Null
    

    Pseudo port-channel = Po25
    

    LACP port-priority  = 128
    

    LACP Wait-time  = 2 secs
    

    LACP Port Identifier = 3
    

    LACP Activity : Active
    

    LACP Timeout : LongLACP Error State : None
    

    

    Aggregation State : Aggregation, Defaulted
    

    

                     LACP Port   Admin  Oper   Port    Port
    

    Port     State   Priority    Key    Key    Number  State
    

    ---------------------------------------------------------------------
    

    Gi0/3    Down    128         25     25     0x3     0xa2
    

    

    Port-channel : Po25
    

    -------------------
    

    

    Number of Ports = 1
    

    HotStandBy port = null
    

    Port state = Port-channel Ag-Not-Inuse
    

    Protocol = LACP
    

    Aggregator-MAC  e8:e8:75:90:5f:9e
    

    Maximum number of Ports  = 8
    

    

    Port-Channel Mtu         = 1500
    

    Port-Channel Speed       = 0 Mbps
    

    Port-Channel High Speed  = 0 Mbps
    

    Port-Channel Member Ports Speed = 0 Mbps
    

    Port-Channel Member Ports High Speed  = 0 Mbps
    

    3.