Link Aggregation Group Recommendations - IBM 8677 - BladeCenter Rack-mountable - Power Supply Planning And Installation Manual

v You must enable the trunk before connecting any cable between the switches to
avoid creating a data loop.
v Disconnect all trunk port cables or disable the trunk ports before removing a port
trunk to avoid creating a data loop.
v The configuration of the lowest numbered port in the group becomes the
configuration for all ports in the port trunking group. This port becomes the
Master Port of the group. All configuration options applied to the Master Port are
also applied to the entire port trunking group.
v Load balancing is automatically applied to the ports in the trunked group. A link
failure within the group causes the network traffic to be directed to the remaining
links in the group.
v The spanning tree protocol (STP) will treat a port trunking group as a single link
on the switch level. On the port level, the STP will use the port parameters of the
Master Port in the calculation of port cost and in determining the state of the port
trunking group. If two redundant port trunking groups are configured on the
switch, STP will block one entire group in the same way that STP blocks a single
port that has a redundant link.
v Use the Distribution Method to specify the method used to differentiate packets
that go through your network. The method you choose is used as a hashing
function to determine which packets go to which port.
802.3ad link aggregation
Notes:
1. The Mode determines whether or not a port is enabled to join or create a link
aggregation group.
2. The Administrator key controls the way that links are aggregated. Use the same
Administrator key for all ports to be aggregated together.
3. The Operator key is used by the port to communicate with other LACP
switches.

Link aggregation group recommendations

The external ports on a BladeCenter Ethernet switch module can be configured in
these ways:
v Multi-port Link Aggregation Group (LAG) using the Link Aggregation Control
Protocol (LACP) – 1 Gbps per port
v Multi-port Trunk – 1 Gbps per port
v Single port link – 1 Gbps
v Multi-port LAG using LACP – 100 Mbps per port
v Multi-port Trunk, 100 Mbps per port
The recommended configuration is:
v Define the four ports of each Ethernet switch module as a 4-port IEEE 802.3 Link
Aggregation Group (LAG).
v Configure the Link Aggregation Control Protocol (LACP) – define a minimum of 2
ports for an active group within a LAG to provide at least 2 Gbps full-duplex
bandwidth.
By defining a LAG port group and configuring LACP, LACP allows a subset of the
LAG ports to be active meaning 2, 3, or 4 ports are active which provides 2, 3, or 4
Gbps of bandwidth between the BladeCenter unit and the adjacent router or
Chapter 5. Configuration considerations
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