Use the following fields to configure Equal-Cost Multiple Path
disabling, or changing ECMP on an existing virtual router causes
the system to restart the virtual router, which might cause existing
sessions to be terminated.
cause return packets to egress out the same interface on which the
associated ingress packets arrived. That is, the firewall will use
the ingress interface on which to send return packets, rather than
use the ECMP interface, so the
overrides load balancing. This behavior occurs only for traffic
flows from the server to the client.
Select the maximum number of equal-cost
paths: (2, 3, or 4) to a destination network that can be copied
from the RIB to the FIB. Default is 2.
Choose one of the following ECMP load-balancing algorithms to
use on the virtual router. ECMP load balancing is done at the session
level, not at the packet level. This means that the firewall (ECMP)
chooses an equal-cost path at the start of a new session, not each
time a packet is received.
default, the virtual router load balances sessions using this option,
which uses a hash of the source and destination IP addresses in
the packet header to determine which ECMP route to use.
—There are two IP hash methods
that determine which ECMP route to use:
If you select
, by default the firewall uses a hash of the source
and destination IP addresses.
Alternatively, you can select
Use Source Address
(available in PAN-OS 8.0.3 and later releases).
This IP hash method ensures that all sessions belonging to the same
source IP address always take the same path.
Use Source/Destination Ports
include the ports in either hash calculation. You can also enter
value (an integer) to further
randomize load balancing.
Weighted Round Robin
can be used to take into consideration different link capacities
and speeds. Upon choosing this algorithm, the Interface window opens.
and select an
be included in the weighted round robin group. For each interface,
to be used for that interface.
to 100; range is 1-255. The higher the weight for a specific equal-cost
path, the more often that equal-cost path will be selected for a
new session. A higher speed link should be given a higher weight
than a slower link, so that more of the ECMP traffic goes over the
faster link. Click
again to add another
interface and weight.
Balanced Round Robin
ECMP sessions equally across links.