HP 3500 Series Advanced Traffic Management Manual page 220

Quality of Service: Managing Bandwidth More Effectively
Using Quality of Service Policies
Edge Switch
Classify inbound traffic
on these Class-of-
Service (CoS) types:
• IP-device (address)
• Protocol (LAN)
• VLAN-ID (VID).
• Source-Port
Apply 802.1p priority to
selected outbound
traffic on tagged VLANs.
Set Priority
Edge Switch
Classify inbound traffic
on IP-device (address)
and VLAN-ID (VID).
Apply DSCP markers to
selected traffic.
Set Policy
5-2
Control the priority of traffic from dedicated VLANs or applications.
■
■ Change the priorities of traffic from various segments of your network as
your business needs change.
Set priority policies in edge switches in your network to enable traffic-
■
handling rules across the network.
Honor Priority
Downstream
Switch
Tagged VLANs on
inbound and outbound
ports.
Traffic arrives with
priority set by edge
switch
Forward with 802.1p
priority.
Figure 5-1. Example of 802.1p Priority Based on CoS (Class-of-Service) Types and
Use of VLAN Tags
Honor Policy
Downstream
Switch
Traffic arrives with DSCP
markers set by edge
switch
Classify on ToS DiffServ.
Figure 5-2. Example Application of Differentiated Services Codepoint (DSCP)
Policies
Apply QoS to inbound traffic at the network edge. At the edge switch,
QoS classifies certain traffic types and in some cases applies a DSCP policy.
At the next hop (downstream switch) QoS honors the policies established at
the edge switch. Further downstream, another switch may reclassify some
traffic by applying new policies, and yet other downstream switches can be
configured to honor the new policies.
Downstream
Switch
Tagged VLANs on some
or all inbound and
outbound ports.
Classify inbound traffic
on CoS types.
Change priority on
selected CoS type(s).
Forward with 802.1p
priority.
Change Priority
Downstream
Switch
Classify on ToS DiffServ
and Other CoS
Apply new DSCP markers
to selected traffic.
Change Policy
Honor New Priority
Downstream
Switch
Tagged VLANs on at
least some inbound
ports.
Traffic arrives with the
priority set in the VLAN
tag. Carry priority
downstream on tagged
VLANs.
Honor New Policy
Downstream
Switch
Classify on ToS Diffserv