Link Aggregation Standard and Custom Algorithms
Standard Algorithms
The
following are the types of traffic to which standard addressed-based
algorithms apply and the traffic components used to select egress
links:
- Layer 2 frames, Unknown unicast packet and non-IP
traffic—The source and destination MAC addresses.
- IPv4 and IPv6 packets—Load sharing is based on the
configured options supported on each platform:
- L2 algorithm—Layer 2 source and destination MAC
addresses.
- L3 algorithm—Layer 3 source and destination IP
addresses.
- L3_L4 algorithm—Layer 3 and Layer 4, the
combined source and destination IP addresses and source and
destination TCP and UDP port numbers.
- MPLS packets—The source and destination MAC
addresses.
Custom Algorithms
The following are the types of traffic to which custom addressed-based
algorithms apply and the traffic components used to select egress links:
- Non-IP Layer 2—Uses the VLAN ID, the source and destination
MAC addresses, and the ethertype.
- IPv4 packets—Uses IP address information from an IP header,
or for tunneled packets, the custom algorithm always uses the inner header
of an IP-in-IP or GRE tunnel packet. The configuration options are:
- The source and destination IPv4 addresses and
Layer 4 port numbers (default)
- The source IP address only,
- The destination IP address only
- The source and destination IP addresses
- IPv6 packets—Uses the source and destination IPv6 addresses
and Layer 4 port numbers.
- MPLS packets—Uses the top, second, and reserved labels and
the source and destination IP addresses.
![Note](images/note.png)
Note
In a switch having at least one LAG group with custom
algorithm, the egress port for unknown unicast packets across all LAG groups in
switch will be decided based on Layer 3 source and destination IP address.
The following command allows you to enable load sharing and select
either a standard algorithm or specify that you want to use a custom algorithm:
enable sharing port grouping port_list {algorithm [address-based {L2 | L3 | L3_L4 | custom} | port-based }]} {lacp | health-check}
If you choose the custom option when you enable load
sharing, you can use the following command to select a custom load sharing
algorithm:
configure sharing
address-based custom [ipv4 [L3-and-L4 | source-only | destination-only | source-and-destination] | hash-algorithm [xor | crc-16]]
The hash-algorithm option controls how the source
information (such as an IP address) is used to select the egress port. The
xor hash algorithm guarantees that the same egress port is
selected for traffic distribution based on a pair of IP addresses, Layer 4 ports, or
both, regardless of which is the source and which is the destination.
![Note](images/note.png)
Note
Use of the ACL redirect-port-no-sharing
port action overrides any load-sharing algorithm hash that is generated
based on the lookup results. For more information on this action, see
LAG Port Selection.