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Qos over fc routers, Figure 69 – Dell POWEREDGE M1000E User Manual

Page 527

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Fabric OS Administrator’s Guide

527

53-1002745-02

QoS zones

21

NOTE

By default, QoS is enabled on 8-Gbps ports, except for long-distance 8-Gbps ports. QoS is disabled
by default on all 4-Gbps ports and long-distance 8-Gbps ports.

FIGURE 69

QoS with E_Ports enabled

You need to enable QoS on the E_Ports on both ISLs between domain 3 and domain 4, because
either path might be selected to carry the traffic.

You do not need to enable QoS on the E_Ports on the ISLs between domain 1 and domain 2 and
between domain 2 and domain 3, because these are not the shortest paths between the hosts and
the targets. However, if the ISL between domain 1 and domain 3 is broken, then the path through
domain 2 would be used.

To guarantee traffic priority, you should enable QoS on all possible E_Ports. Alternatively, you could
use a TI zone to limit the E_Ports that carry the traffic between a “host,target” pair and enable QoS
on only those E_Ports.

If QoS is not enabled on an E_Port, the traffic prioritization stops at that point. For example, in

Figure 69

if you disabled QoS on E_Ports “3,12” and “3,13,” then the traffic from H1 and H2 to S3

would be low priority from the hosts to domain 3, but would switch to the default (medium) priority
from domain 3 to the target S3.

QoS over FC routers

QoS over FC routers uses QoS traffic prioritization between devices in edge fabrics over an FC
router. See

Chapter 24, “Using FC-FC Routing to Connect Fabrics,”

for information about FC routers,

phantom switches, and the FC-FC Routing Service.

To establish QoS over FC routers, you must do the following:

Define QoS zones in each edge fabric.

Define LSAN zones in each edge fabric.

Enable QoS on the E_Ports in each edge fabric.

Enable QoS on the EX_Ports in the backbone fabric.

See

“Setting QoS zone-based traffic prioritization over FC routers”

on page 532 for detailed

instructions.

7

12

3

14

15

16

8

13

Domain 1

Domain 3

Domain 4

Domain 2

H1

1

9

S3

S2

S1

H2

= High priority

= Medium priority

= Low priority

= E_Ports with
QoS enabled