Quality of Service (QoS): Managing Bandwidth More Effectively
Introduction
Precedence | Criteria | Overview |
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6 | Incoming | Where a | ||
| 802.1p | VLAN, if QoS is not configured to override the packet’s priority setting, the switch uses the | ||
| Priority | packet’s existing 802.1p priority (assigned by an upstream device or application) to determine | ||
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| which inbound and outbound port queue to use. If there is no QoS policy match on the packet, | ||
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| and it then leaves the switch through a port that is a tagged member of the VLAN, then there | ||
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| is no change to its 802.1p priority setting. If the packet leaves the switch through a port that is | ||
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| an untagged member of the VLAN, the 802.1p priority is dropped. | ||
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| Entering | Outbound Port | Exiting |
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| (Inbound) 802.1p | Queue | (Outbound) |
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| Priority |
| 802.1p Priority |
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| 1 - 2 | Low | 1 - 2 |
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| 0 - 3 | Normal | 0 - 3 |
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| 4 - 5 | Medium | 4 - 5 |
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| 6 - 7 | High | 6 - 7 |
If a packet does not meet the criteria for Incoming 802.1p priority, then the packet goes to the “normal” outbound queue of the appropriate port. If the packet entered the switch through a port that is an untagged member of a VLAN, but exits through a