Queue#

QoS → QQueues

Queues are intermediary first-in, first-out storage systems for packets as they are processed by a router. Although support depends on the hardware platform, generally there are queues for ingressing packets and for egressing packets.

When a packet arrives on a network element, the packet is classified by an IngressPolicy based on packet headers - the classification (priority level) of the packet is called a forwarding class. Based on this forwarding class, the packet is assigned to a Queue with a particular size (which can be static or dynamically growing/shrinking). From there, a scheduler visits all queues to dequeue packets for processing.

After the router decides where the packet should go, it goes through the same process on egress: based on the forwarding class that is attached to the packet, an EgressPolicy determines which egress Queue for that particular (sub)interface the packet will be added to. Again, a (port-specific) scheduler visits the queues in order of priority and dequeues packets that are then being forwarded out of the interface.

The information above is an abstracted and simplified view. The reality and OS-specific implementations introduce a lot of nuance and sometimes restrictions that need to be taken into account when designing a QoS architecture. For a full understanding of your network behavior, refer to the OS-specific documentation.

Several Queue resources are created by default when deploying EDA. They can be used as-is for unicast traffic or overwritten.

PFC#

Priority-based Flow Control or PFC is a mechanism (IEEE 802.1Qbb) that enables a network element to signal to one of their neighbors to stop sending traffic for a particular priority. When the queue depth (on ingress) exceeds the pfcOnThresholdPercent property of a Queue of an IngressPolicy, the switch will send out a PFC frame out of that interface to stop sending traffic for that particular priority.

Dependencies#

The Queue resource does not have any dependencies on other EDA resources.

Referenced resources#

The Queue resource does not reference any other EDA resources.

Examples#

apiVersion: qos.eda.nokia.com/v2
kind: Queue
metadata:
  labels:
    eda.nokia.com/bootstrap: 'true'
  name: pfc-5
  namespace: eda
spec:
  queueID: 5
  queueType: PFC
  trafficType: Unicast

cat << 'EOF' | kubectl apply -f -
apiVersion: qos.eda.nokia.com/v2
kind: Queue
metadata:
  labels:
    eda.nokia.com/bootstrap: 'true'
  name: pfc-5
  namespace: eda
spec:
  queueID: 5
  queueType: PFC
  trafficType: Unicast
EOF

Custom Resource Definition#

To browse the Custom Resource Definition go to crd.eda.dev.