Quality of Service (QoS) provides preferential treatment to specific traffic that is received on multiple ingress interfaces or Test Access Points (TAPs). QoS aggregates, filters, and forwards traffic to a monitoring tool on an egress interface or an egress group. The forwarding decision is based on the access control lists (ACLs) and route maps applied on the aggregated logical interface or port channel.
QoS allows a networking device prioritize critical traffic steams and provides dedicated bandwidth for effective delivery. In the case of network conjunctions, QoS can selectively drop the low priority streams to allow high priority traffic to pass through. QoS manages traffic delivery using queues, buffers, and schedulers to use the available resources for maximum throughput.
QoS supports eight queues per egress port on a device. The highest queue priority is q7 and q0 (default) is the lowest queue priority. Queue properties cannot be altered, although you can use the queue command to change a queue name.
When you configure a route-map, you can attach a QoS forwarding group name and queue priority. The ACL inherits the configuration.
The NPB application uses ACLs to classify and forward packets. An ACL can have multiple access control entries (ACEs). Each ACE has a match criterion and an action. The match criteria are the SAP, IPv4, IPv6, and MAC addresses, VLAN ID, and L4 ports. The actions are to permit or deny, log, and count. When a packet matches the criteria, the specified action is taken for the packets.
Additionally, the ACE includes a QoS forwarding group. You can configure the QoS forwarding group as an optional action in each ACE. If a packet matches the ACE match criteria, the packet is treated with the QoS configurations present in the attached QoS forwarding group.
Several commands support QoS configuration:
descriptionseq (IPv4 access list)seq (IPv6 access list)seq (MAC access list)show running-config qosFor more information, see: