Quality of Service 72
Table 15 Well-known application ports
Number TCP/UDP
Application
Number TCP/UDP
Application
Number TCP/UDP
Application
69 tftp 161 snmp 1985
70 gopher 162 snmptrap
Table 16 Well-krown TCP flag values
Flag Value
URG 0x0020
ACK 0x0010
PSH 0x0008
RST 0x0004
SYN 0x0002
FIN 0x0001
• Packet Format
• Ethernet format (eth2, SNAP, LLC)
• Ethernet tagging format
• Egress port packets
Note that the egress port ACL will not match a broadcast, multicast, unknown unicast, or Layer 3 packet. The
egress port ACL will not match packets if the destination port is a trunk member.
Summary of ACL actions
Actions determine how the traffic is treated. The GbE2c QoS actions include the following:
• Pass or Drop
• Re-mark a new DiffServ Code Point (DSCP)
• Re-mark the 802.1p field
• Set the COS queue
Understanding ACL precedence
Each ACL has a unique precedence level, based on its number. When an incoming packet matches the highest
precedence ACL, the ACL’s configured action takes place. The other assigned ACLs also are considered, in order of
precedence.
ACLs are divided into Precedence Groups, as shown in the following table. Each Precedence Group provides a
different set of packet classifiers for the ACLs within the Precedence Group.
Table 17 ACI Precedence Groups
Precedence Group ACLs Packet Classifiers Precedence Level
Precedence Group 1 ACL 1 – ACL 127
Source MAC address
Destination MAC address
Ethernet Type
VLAN ID
802.1p
Packet Format
Low
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