INS_CWGE10FX2TX8MSPOE 02/19/21 PAGE 46
INSTALLATION AND OPERATION MANUAL
CWGE10FX2TX8MSPOE
TECH SUPPORT: 1.888.678.9427
The type of service is used to specify the treatment of the datagram during its transmission
through the internet system. Example mappings of the internet type of service to the actual
service provided on networks such as AUTODIN II, ARPANET, SATNET, and PRNET is given in
“Service Mappings”.
The Network Control precedence designation is intended to be used within a network only.
The actual use and control of that designation is up to each network. The Internetwork Control
designation is intended for use by gateway control originators only.
If the actual use of these precedence designations is of concern to a particular network, it is the
responsibility of that network to control the access to, and use of, those precedence designations.
DSCP Priority
DSCP Priority
DSCP Priority
0 0 1 0 2 0
. . .
60
0 61
0 62
0
63 0
Example:
IP Header
DSCP=50
45 C8 . . .
Queuing Algorithms
Queuing algorithms allow switches to maintain separate queues for packets from each individual
source or flow and prevent a source from monopolizing the bandwidth.
Strict-Priority (SPQ)
Strict-Queuing will empty the four hardware priority queues in order, beginning with the highest
priority queue, 3, to the lowest priority queue, 0. Each hardware queue will transmit all of the
packets in its buffer before permitting the next lower priority to transmit its packets. When the
lowest hardware priority queue has finished transmitting all of its packets, the highest hardware
priority queue will begin transmitting any packets it may have received.
Weighted Fair Queuing (WFQ)
WFQ is a data packet scheduling technique allowing different scheduling priorities to statistically
multiplexed data flows. It provides traffic priority management that automatically sorts among
individual traffic streams without requiring an access list. WFQ decides which queue is selected
in one slot time to guarantee the minimal packet rate of one queue. Thus, WFQ allows Internet
operators to define traffic classes and then assign different bandwidth proportions.
Weighted round robin (WRR)
Round Robin scheduling services queues on a rotating basis and is activated only when a port
has more traffic than it can handle. A queue is given an amount of bandwidth irrespective of the
incoming traffic on that port. This queue then moves to the back of the list. The next queue is
given an equal amount of bandwidth, and then moves to the end of the list; and so on, depending
on the number of queues being used. This works in a looping fashion until a queue is empty.
