Hash-based algorithms prioritize session stickiness
—The
IP
Modulo
and
IP Hash
algorithms use
hashes based on information in the packet header, such as source
and destination address. Because the header of each flow in a given
session contains the same source and destination information, these
options prioritize session
stickiness. If you choose
the
IP Hash
algorithm, the hash can be based
on the source and destination addresses, or the hash can be based
on the source address only (in PAN-OS 8.0.3 and later releases).
Using an IP hash based on only the source address causes all sessions
belonging to the same source IP address to always take the same
path from available multiple paths. Thus the path is considered
sticky and is easier to troubleshoot if necessary. You can optionally
set a
Hash Seed
value to further randomize
load balancing if you have a large number of sessions to the same
destination and they’re not being distributed evenly over the ECMP
links.