User guide

4-8 E
XTREME
W
ARE
S
OFTWARE
U
SER
G
UIDE
C
ONFIGURING
B
LACK
D
IAMOND AND
A
LPINE
S
WITCH
S
LOTS AND
P
ORTS
For example, VLANs see the load-sharing group as a single logical port. Most
load-sharing algorithms guarantee packet sequencing between clients.
If a port in a load-sharing group fails, traffic is redistributed to the remaining ports in
the load-sharing group. If the failed port becomes active again, traffic is redistributed to
include that port.
Load sharing must be enabled on both ends of the link, or a network loop may
result. The load-sharing algorithms do not need to be the same on both ends.
This feature is supported between Extreme Networks switches only, but may be
compatible with third-party “trunking” or link-aggregation algorithms. Check with an
Extreme Networks technical representative for more information.
L
OAD
-S
HARING
A
LGORITHMS
Load sharing algorithms allow you to select the distribution technique used by the
load-sharing group to determine the output port selection. Algorithm selection is not
intended for use in predictive traffic engineering. You can configure one of three
load-sharing algorithms on the switch, as follows:
• Port-based — Uses the ingress port to determine which physical port in the
load-sharing group is used to forward traffic out of the switch.
• Address-based — Uses addressing information to determine which physical port in
the load-sharing group to use for forwarding traffic out of the switch. Addressing
information is based on the packet protocol, as follows:
— IP packets — Uses the source and destination MAC and IP addresses, and the
TCP port number.
— IPX packets — Uses the source and destination MAC address, and IPX network
identifiers.
— All other packets — Uses the source and destination MAC address.
• Round-robin — When the switch receives a stream of packets, it forwards one packet
out of each physical port in the load-sharing group using a round-robin scheme.
Using the round-robin algorithm, packet sequencing between clients is not
guaranteed.
If you do not explicitly select an algorithm, the port-based scheme is used. However,
the address-based algorithm has a more even distribution and is the recommended
choice.