Quality of Service (QoS): Managing Bandwidth More Effectively

QoS Operating Notes and Restrictions

QoS Operating Notes and Restrictions

QoS support based on packet type is shown below.

Table 5-11. Details of Packet Criteria and Restrictions for QoS Support

Packet Criteria or

 

QoS Classifiers

 

DSCP

Restriction

 

 

 

 

Overwrite

 

 

 

 

 

(Re-

 

Device

IP Type-of-

Source

Incoming

 

Marking)

 

Priority (IP

Service

Port

802.1p

 

 

Address)

 

 

 

 

 

 

 

 

 

 

Restricted to IPv4 Packets Only

Yes

Yes

No

No

Yes

 

 

 

 

 

 

Allow Packets with IP Options1

Yes

Yes

Yes

Yes

Yes

Support IPv6 Packets2

No

No

Yes

Yes

No

Support Layer-2 SAP

No

No

Yes

Yes

No

Encapsulation

 

 

 

 

 

1An “IP Option” is an optional, extra field in the header of an IP packet.

2All Switches: For explicit QoS support of IPv6 packets, force IPv6 traffic into its own set of VLANs and then configure VLAN-based classifiers for those VLANs.

All Switches: For explicit QoS support of IP subnets, ProCurve recom- mends forcing IP subnets onto separate VLANs and then configuring VLAN-based classifiers for those VLANs.

For Devices that Do Not Support 802.1Q VLAN-Tagged Ports: For communication between these devices and the switch, connect the device to a switch port configured as Untagged for the VLAN in which you want the device’s traffic to move.

Port Tagging Rules: For a port on the switch to be a member of a VLAN, the port must be configured as either Tagged or Untagged for that VLAN. A port can be an untagged member of only one VLAN of a given protocol type. Otherwise, the switch cannot determine which VLAN should receive untagged traffic. For more on VLANs, refer to chapter 2, “Static Virtual LANs (VLANs)”.

Maximum QoS Configuration Entries: The switches covered in this guide accept the maximum outbound priority and/or DSCP policy config- uration entries. They support a maximum of 250 QoS entries. Each device (IP address) QoS configuration uses two entries. Each TCP/UDP port QoS configuration uses two entries. All other classifier configurations use one entry each.

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