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About PortChanneling and Trunking
S e n d d o c u m e n t a t i o n c o m m e n t s t o m d s f e e d b a c k - d o c @ c i s c o . c o m .
About PortChanneling and Trunking
Trunking is a commonly-used storage industry term. However, the Cisco SAN-OS software and switches
in the Cisco MDS 9000 Family implement trunking and PortChanneling as defined below:
•
•
See
Figure 13-2
Switch 1
Figure 13-3
Switch 1
Port Channeling
PortChanneling and trunking are used separately across an ISL:
•
•
Both PortChanneling and trunking can be used between TE ports over EISLs.
About Load Balancing
Two mechanisms support the load balancing functionality:
•
•
Cisco MDS 9000 Family Configuration Guide
13-4
PortChanneling enables several physical links to be combined into one aggregated logical link.
Trunking enables a link transmitting frames in the EISL format to carry (trunk) multiple VSAN
traffic. When trunking is operational on an E port, that E port becomes a TE port. A TE port is
specific to switches in the Cisco MDS 9000 Family. An industry standard E port can link to other
vendor switches and is referred to as a nontrunking interface (see
Chapter 12, "Configuring Trunking"
Trunking Only
Any other
switch
ISL
E port
E port
PortChanneling and Trunking
Switch 2
ISL 1
ISL 2
ISL 3
PortChanneling—Interfaces can be channeled between E ports and TE ports.
Trunking—Trunking, which permits carrying traffic on multiple VSANs between switches, can be
done only between TE ports.
See
Chapter 16, "Configuring and Managing VSANs."
Flow based—All frames between source and destination follow the same links for a given flow. That
is, whichever link is selected for the first exchange of the flow is used for all subsequent exchanges.
Exchange based—The first frame in an exchange picks a link and subsequent frames in the exchange
follow the same link. However, subsequent exchanges can use a different link. This provides more
granular load balancing while preserving the order of frames for each exchange.
for information on trunked interfaces.
Switch 1
EISL
TE port
TE port
Trunking
Switch 1
EISL 1
EISL 2
EISL 3
PortChanneling
and trunking
Chapter 13
Configuring PortChannels
Figure 13-2
and
Figure
Switch 2
Switch 2
OL-6973-03, Cisco MDS SAN-OS Release 2.x
13-3).
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