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    <title>Oversubscription Ratio Restrictions </title>
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<a name="wp1075203"> </a><h1 class="pTitle">
Oversubscription Ratio Restrictions

</h1>
<a name="wp1075206"> </a><p class="pBody">
The 48-port and 24-port 4-Gbps, and all 8-Gbps Fibre Channel switching modules support 
oversubscription on switches with shared rate mode configurations. By default, all 48-port and 24-port 
4-Gbps, and 8-Gbps Fibre Channel switching modules have restrictions on oversubscription ratios 
enabled. As of Cisco SAN-OS Release 3.1(1) and NX-OS Release 4.1(1), you can disable restrictions 
on oversubscription ratios. 

</p>
<a name="wp1075210"> </a><p class="pBody">
<a href="gen217.html#wp1075218">Table&#160;13-9</a> describes the bandwidth allocation for oversubscribed interfaces configured in shared mode 
on the 4-Gbps and 8-Gbps modules.

</p>
<a name="wp1075407"> </a><p class="pBodyRelative">
</p><div>
<table border="2" cellpadding="2" id="wp1075218table1075211">
  <caption><a name="wp1075218"> </a><div class="pTableTitle">
Table&#160;13-9	Bandwidth Allocation for Oversubscribed Interfaces&#160;

</div>
</caption>
  <tr bgcolor="#CCCCCC" align="left" valign="middle">    <th colspan="1" rowspan="2"><a name="wp1075228"> </a><p class="pCellHeading">
Switching 
Module

</p>
</th>
    <th colspan="1" rowspan="2"><a name="wp1075230"> </a><p class="pCellHeading">
Configured Speed

</p>
</th>
    <th colspan="2" rowspan="1"><a name="wp1075232"> </a><p class="pCellHeading">
Reserved Bandwidth (Gbps)

</p>
</th>
    <th colspan="1" rowspan="2"><a name="wp1075236"> </a><p class="pCellHeading">
Maximum 
Bandwidth 
(Gbps)

</p>
</th>
</tr>
  <tr bgcolor="#CCCCCC" align="left" valign="middle">    <th><a name="wp1075242"> </a><p class="pCellHeading">
Ratios enabled

</p>
</th>
    <th><a name="wp1075244"> </a><p class="pCellHeading">
Ratios disabled

</p>
</th>
</tr>
  <tr align="left" valign="top">    <td colspan="1" rowspan="3"><a name="wp1075278"> </a><p class="pBody">
24-Port 8-Gbps 
Fibre Channel 
Module

</p>
</td>
    <td><a name="wp1075280"> </a><p class="pBody">
Auto 8 Gbps

</p>
</td>
    <td><a name="wp1075282"> </a><p class="pBody">
0.8

</p>
</td>
    <td><a name="wp1075284"> </a><p class="pBody">
0.8

</p>
</td>
    <td><a name="wp1075286"> </a><p class="pBody">
8

</p>
</td>
</tr>
  <tr align="left" valign="top">    <td><a name="wp1075290"> </a><p class="pBody">
Auto Max 4 Gbps

</p>
</td>
    <td><a name="wp1075292"> </a><p class="pBody">
0.4

</p>
</td>
    <td><a name="wp1075294"> </a><p class="pBody">
0.4

</p>
</td>
    <td><a name="wp1075296"> </a><p class="pBody">
4

</p>
</td>
</tr>
  <tr align="left" valign="top">    <td><a name="wp1075300"> </a><p class="pBody">
Auto Max 2 Gbps

</p>
</td>
    <td><a name="wp1075302"> </a><p class="pBody">
0.2

</p>
</td>
    <td><a name="wp1075304"> </a><p class="pBody">
0.2

</p>
</td>
    <td><a name="wp1075306"> </a><p class="pBody">
2

</p>
</td>
</tr>
  <tr align="left" valign="top">    <td colspan="1" rowspan="4"><a name="wp1075308"> </a><p class="pBody">
4/44-Port 
8-Gbps 
Host-Optimized 
Fibre Channel 
Module

</p>
</td>
    <td><a name="wp1075310"> </a><p class="pBody">
8 Gbps

</p>
</td>
    <td><a name="wp1075312"> </a><p class="pBody">
0.87

</p>
</td>
    <td><a name="wp1075314"> </a><p class="pBody">
0.16

</p>
</td>
    <td><a name="wp1075316"> </a><p class="pBody">
8

</p>
</td>
</tr>
  <tr align="left" valign="top">    <td><a name="wp1075320"> </a><p class="pBody">
Auto Max 4 Gbps

</p>
</td>
    <td><a name="wp1075322"> </a><p class="pBody">
0.436

</p>
</td>
    <td><a name="wp1075324"> </a><p class="pBody">
0.08

</p>
</td>
    <td><a name="wp1075326"> </a><p class="pBody">
4

</p>
</td>
</tr>
  <tr align="left" valign="top">    <td><a name="wp1075330"> </a><p class="pBody">
Auto Max 2 Gbps

</p>
</td>
    <td><a name="wp1075332"> </a><p class="pBody">
0.218

</p>
</td>
    <td><a name="wp1075334"> </a><p class="pBody">
0.04

</p>
</td>
    <td><a name="wp1075336"> </a><p class="pBody">
2

</p>
</td>
</tr>
  <tr align="left" valign="top">    <td><a name="wp1075340"> </a><p class="pBody">
1 Gbps

</p>
</td>
    <td><a name="wp1075342"> </a><p class="pBody">
0.109

</p>
</td>
    <td><a name="wp1075344"> </a><p class="pBody">
0.02

</p>
</td>
    <td><a name="wp1075346"> </a><p class="pBody">
1

</p>
</td>
</tr>
  <tr align="left" valign="top">    <td colspan="1" rowspan="3"><a name="wp1075348"> </a><p class="pBody">
48-port 4-Gbps 
Fibre Channel 
switching 
module

</p>
</td>
    <td><a name="wp1075350"> </a><p class="pBody">
Auto 4 Gbps

</p>
</td>
    <td><a name="wp1075352"> </a><p class="pBody">
0.8

</p>
</td>
    <td><a name="wp1075354"> </a><p class="pBody">
0.09

</p>
</td>
    <td><a name="wp1075356"> </a><p class="pBody">
4

</p>
</td>
</tr>
  <tr align="left" valign="top">    <td><a name="wp1075360"> </a><p class="pBody">
Auto Max 2 Gbps

</p>
</td>
    <td><a name="wp1075362"> </a><p class="pBody">
0.4

</p>
</td>
    <td><a name="wp1075364"> </a><p class="pBody">
0.045

</p>
</td>
    <td><a name="wp1075366"> </a><p class="pBody">
2

</p>
</td>
</tr>
  <tr align="left" valign="top">    <td><a name="wp1075370"> </a><p class="pBody">
1 Gbps

</p>
</td>
    <td><a name="wp1075372"> </a><p class="pBody">
0.2

</p>
</td>
    <td><a name="wp1075374"> </a><p class="pBody">
0.0225

</p>
</td>
    <td><a name="wp1075376"> </a><p class="pBody">
1

</p>
</td>
</tr>
  <tr align="left" valign="top">    <td colspan="1" rowspan="3"><a name="wp1075378"> </a><p class="pBody">
24-port 4-Gbps 
Fibre Channel 
switching 
module

</p>
</td>
    <td><a name="wp1075380"> </a><p class="pBody">
Auto 4 Gbps

</p>
</td>
    <td><a name="wp1075382"> </a><p class="pBody">
1

</p>
</td>
    <td><a name="wp1075384"> </a><p class="pBody">
0.27

</p>
</td>
    <td><a name="wp1075386"> </a><p class="pBody">
4

</p>
</td>
</tr>
  <tr align="left" valign="top">    <td><a name="wp1075390"> </a><p class="pBody">
Auto Max 2 Gbps

</p>
</td>
    <td><a name="wp1075392"> </a><p class="pBody">
0.5

</p>
</td>
    <td><a name="wp1075394"> </a><p class="pBody">
0.135

</p>
</td>
    <td><a name="wp1075396"> </a><p class="pBody">
2

</p>
</td>
</tr>
  <tr align="left" valign="top">    <td><a name="wp1075400"> </a><p class="pBody">
1 Gbps

</p>
</td>
    <td><a name="wp1075402"> </a><p class="pBody">
0.25

</p>
</td>
    <td><a name="wp1075404"> </a><p class="pBody">
0.067

</p>
</td>
    <td><a name="wp1075406"> </a><p class="pBody">
1

</p>
</td>
</tr>
</table>
</div>
<p class="pBodyRelative">
</p>
<a name="wp1075408"> </a><p class="pBody">
All ports in the 48-port and 24-port 4-Gbps modules can be configured to operate at 4 Gbps in shared 
mode even if other ports in the port group are configured in dedicated mode, regardless of available 
bandwidth. However, when oversubscription ratio restrictions are enabled, you may not have all shared 
4-Gbps module ports operating at 4 Gbps. 

</p>
<a name="wp1075409"> </a><p class="pBody">
All ports in the 48-port, 32-Port, and 24-port 8-Gbps modules can be configured to operate at 8 Gbps in 
shared mode even if other ports in the port group are configured in dedicated mode, regardless of 
available bandwidth. However, when oversubscription ratio restrictions are enabled you may not have 
all shared 8-Gbps module ports operating at 8 Gbps. 

</p>
<a name="wp1075410"> </a><p class="pBody">
On the 48-port, 32-Port, and 24-port 8-Gbps modules, if you have configured one 8-Gbps dedicated port 
in one port group, no other ports in the same port group can be configured to operate at 8-Gbps dedicated 
mode. You can have any number of 8-Gbps shared and 4-Gbps dedicated or shared ports. On the 
4/44-port 8-Gbps module, only one port per port group can be configured in 8-Gbps dedicated or shared 
mode.

</p>
<a name="wp1075411"> </a><p class="pBody">
In the following example, a 24-port 4-Gbps module has oversubscription ratios enabled and three 
dedicated ports in one port group operating at 4-Gbps. No other ports in the same port group can be 
configured to operate at 4 Gbps.

</p>
<a name="wp1075431"> </a><p class="pBody">
For dedicated ports, oversubscription ratio restrictions do not apply to the shared pool in port groups. So 
if oversubscription ratio restrictions are disabled, and you have configured three 4-Gbps dedicated ports 
in one port group, then you can configure all other ports in the same port group to operate at a shared 
rate of 4 Gbps. 

</p>
<a name="wp1075432"> </a><p class="pBody">


</p>
<a name="wp1075468"> </a><p class="pBody">
When disabling restrictions on oversubscription ratios, all ports in shared mode on 48-port and 24-port 
4-Gbps or any 8-Gbps Fibre Channel switching modules must be shut down. When applying restrictions 
on oversubscription ratios, you must take shared ports out of service. 

</p>
<a name="wp1075469"> </a><p class="pBodyAutonumNoRule">
<strong>Note	&nbsp;&nbsp;&nbsp;</strong> When restrictions on oversubscription ratios are disabled, the bandwidth allocation among the shared 
ports is proportionate to the configured speed. If the configured speed is auto on Generation 2 modules, 
then bandwidth is allocated assuming a speed of 4 Gbps. For example, if you have three shared ports 
configured at 1, 2, and 4 Gbps, then the allocated bandwidth ratio is 1:2:4. <br />
As of Cisco SAN-OS Release 3.0 and NX-OS Release 4.1(1) or when restrictions on oversubscription 
ratios are enabled, the port bandwidths are allocated in equal proportions, regardless of port speed, so, 
the bandwidth allocation for the same three ports mentioned in the example would be 1:1:1.

</p>
<hr /><br><p class="pBody">Copyright 2010-2013, Cisco Systems, Inc. All rights reserved.</p> 

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