Managing Switches
Configuring Switch Features
Guidelines for Configuring CoS Priorities
Using CoS in a tagged VLAN environment controls the following:
■ Outbound port
■ Outbound 802.1p
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| packet or the packet’s existing 802.1p setting. This enables the packet to | |
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| carry an 802.1p priority to the next downstream device. | |
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| Using CoS without a tagged VLAN environment affects only the outbound port | |
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| queue to which a packet is sent. It prioritizes traffic flow only within the | |
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| switch. However, without a tagged VLAN environment, an outbound packet | |
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| cannot carry an 802.1p priority setting to a downstream device. | |
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N o t e | If you use HP TopTools for Hubs & Switches to configure Quality of Service | |||
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| (QoS) policy in a network, it overrides any CoS settings configured through | |
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| the console or the web browser interface in any individual HP Procurve | |
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| switch. |
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| Steps for Configuring CoS Priority | |
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| The following table shows the Priority Criteria and their precedence. | |
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| Table | |
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| Precedence |
| Criteria | Description |
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| 1 |
| Device Priority (IP Address | You can specify a priority for any packet having a particular destination |
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| or source IP address. It is recommended that you prioritize server |
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| addresses instead of client addresses in order to include the widest |
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| possible range of traffic in your device priority policy. If an outbound |
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| packet has an IP address as the destination, it takes precedence over |
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| another outbound packet that has the same IP address as a source. |
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| (This can occur, for example, on an outbound port in a switch mesh |
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| environment.) Default state: No IP address prioritization. |
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| If a packet does not meet the criteria for device priority, then |
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| precedence defaults to IP Type of Service (ToS) criteria, below. |
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| 2 |
| IP | Applies only to IP packets. The ToS field in an IP packet is configured |
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| Service (ToS) | by an upstream device or application before the incoming packet |
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| enters the switch, and is not altered by the switch. The switch reads |
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| the packet’s Type of Service (ToS) field and prioritizes the packet (if |
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| specified in the CoS configuration) for outbound transmission. The |
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| default state is Disabled. |
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| If a packet does not meet the criteria for ToS priority, then precedence |
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| defaults to Protocol criteria, below. |
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