Figure 4 Fifo Scheduling - Zte ZXR10 5900 Product Description

been classified, QoS features can be applied to the different types, to perform class-
based congestion management and traffic shaping.
Network administrators can configure the policy for classifying packets. This policy not
only includes in-band identifications parameters such as IP priority or DSCP value of IP
packet and CoS value of 802.1p, but can also specify input interface, source address,
destination address, MAC address, IP protocol or application port number, etc. The
classification result is beyond scope limits, which can be a flow determined by the
quintuple (source address, source port number, protocol number, destination address,
destination port number), or all packets destined toward a network segment. The ACL,
especially the expanded ACL technology, can be used to classify packets into different
types based on different requirements.
Usually when packets are classified at the edge network, IP priority or DSCP is marked
at the same time in order to simply use the IP priority or DSCP as the criteria for
classification inside the network. And this priority can be used by queuing technology to
process packets differently. Downstream networks can selectively receive the classified
results from upstream, or re-classify the packet flow based on their own classification
criteria.
For example, perform classification and marking at the edge network as follows:
To aggregate all VOIP data packets into the EF ToS, and mark the packet IP priority as 5
or the DSCP value as EF aggregate all VOIP control packets into the AF ToS, and the
packet IP priority as 4, or the DSCP value as AF31.
When packets are marked and classified at the edge network, differentiated services can
be provided to different type's traffic in the intermediate nodes of the network according
to the labels. For example, the delay and less jitter are ensured for packets of the EF
ToS in the above example, and are put under traffic policing, while for the AF ToS,
appropriate bandwidth is still assured even during traffic congestion, etc.
3.19.2.2 Congestion Management
Congestion management usually employs queuing technology, which packets are
temporarily buffered into queues inside the router based on appropriate policies, and
withdraw from the queue by certain scheduling policy before being sent out of the
interface. Depending on the in-queue and out-queue policy, congestion management
can be classified as follows:
1. First In First Out Queuing, FIFO
Figure 4 FIFO Scheduling
As indicated in Figure 4, instead of classifying the packets, the FIFO queuing (FIFO
hereinafter) accepts the packets into the queue based on their arriving sequence at the
interface when the speed of the packets arriving at the interface is faster than the speed
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ZXR10 5900 5200 Product Description
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