Industrial Communication Systems

19-6 Industrial Communication Systems

• Queuing is used to evaluate the priority value and the congured police and to determine in

which

of th

e

ou

tput

qu

eues

th

e

pa

cket

mu

st

be pu

t.

•

Scheduling

is

the

process

that

services

the

transmit

queues,

based

on

the

sharing

and

shaping

conguration

of th

e

tr

ansmit

po

rt.

•

Dropping

is

used

to

drop

packets,

to

take

advantage

of

Transmission

Control

Protocol

(TCP)

and

windowing

mechanisms

that

drop

selectively

some

packets

in

an

attempt

to

avoid

dropping

much

more

packets.

is

does

not

work

with

applications

using

User

Datagram

Protocol

(UDP)

as

the

transport

pr

otocol,

on

ly

fo

r

th

e

TC

P

on

es.

By

the

other

side,

the

QoS

features

must

be

congured

throughout

the

network

for

providing

end-to-

end

Qo

S

de

liver ...