User guide

24 Dell PowerConnect 55xx Systems User Guide
are established or enforced. 802.1p is a spin-off of the 802.1Q (VLANs)
standard. 802.1p establishes eight levels of priority, similar to the IP
Precedence IP Header bit-field.
Advanced QoS
Frames that match an ACL and were permitted entrance are implicitly
labeled with the name of the ACL that permitted their entrance. Advanced
mode QoS actions defined in network policies can then be applied to these
flows.
The switch can set DSCP values and map IPv6 DSCP to egress queues in the
same way it does for IPv4. The switch detects IPv6 frames by the IPv6 ether-
type.
For more information about Advanced QoS, see "QoS Advanced Mode" on
page 668.
TCP Congestion Avoidance
The TCP Congestion Avoidance feature activates an algorithm that breaks up
or prevents TCP global synchronization on a congested node, where the
congestion is due to multiple sources sending packets with the same byte
count.
For more information, see "The following is an example of the CLI
commands:" on page 656.
Device Management Features
SNMP Alarms and Trap Logs
The system logs events with severity codes and timestamps. Events are sent as
SNMP traps to a Trap Recipient List.
For more information, see "SNMP" on page 307
.