Configuration Guide User guide

1968 FastIron Configuration Guide
53-1002494-02
QoS overview
Figure 222 illustrates how FastIron WS and Brocade FCX and ICX series devices determine the trust
level of a packet. As shown in the flowchart, the first criteria considered is whether the packet
matches on an ACL that defines a priority. If this is not the case and the MAC address of the packet
matches a static entry, the packet is classified with the priority of the static MAC entry. If neither of
these is true, the packet is next classified with the ingress port default priority. then DSCP/ToS
value, then 802.1p CoS value, and finally the default priority of zero (0).
FIGURE 222 Determining a packet trust level - FastIron WS and Brocade FCX Series and ICX devices
Packet received on
ingress port
Ye s
No
Ye s
Ye s
No
No
Ye s
No
Does the MAC
address match a
static entry?
Does the port
have default
priority?
Does the port
have Trust
DSCP enable?
Trust the priority
of the static
MAC entry
Trust the DCSP-
CoS-mapping or
the DSCP-marking
Trust the port’s
default priority
Trust the DSCP/
ToS value
Trust the 802.1p
CoS value
Use the default
priority of 0
Ye s
Does the
packet match an
ACL that defines
a priority?
No
Is the packet
tagged?