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Ingress Data
The Router can control outgoing data fairly easily. It can queue packets, delay them,
give precedence to other packets, or drop them. This helps in resolving upload (Tx)
traffic bottlenecks, and in most cases is sufficient. However, in the case of download
(Rx) traffic bottlenecks, the ability to control the flow is much more limited. The
Router cannot queue packets, since in most cases the local network (
faster then the Internet (
Internet, it passes it immediately to the local network.
o
for ingress data has the following limitations, which do not exist for outgoing data:
Q
S
•
o
can only be applied to
Q
S
• No borrowing mechanism
• When reserving Rx bandwidth, it is strictly taken from the bandwidth of all
other classes
Furthermore, the Router cannot control the behavior of the
have proper
o
handling. Unfortunately, this is a common situation. Let's look
Q
S
at a scenario of downloading a large file and surfing the Internet at the same time.
Downloading the file is distinguished by small requests, followed by very large
responses. This may result in blocking
situation is limiting the bandwidth of low-priority
download).
Differentiated Services Code Point Settings
In order to understand what
Differentiated Services model.
Differentiated Services (Diffserv) is a Class of Service (Co
best-effort Internet services by differentiating traffic by users, service requirements,
and other criteria. Packets are specifically marked, allowing network nodes to
provide different levels of service, as appropriate for voice calls, video playback, or
other delay-sensitive applications, via priority queuing or bandwidth allocation, or
by choosing dedicated routes for specific traffic flows.
Diffserv defines a field in
Codepoint (
). Hosts or routers passing traffic to a Diffserv-enabled network
DSCP
will typically mark each transmitted packet with an appropriate
markings are used by Diffserv network routers to appropriately classify packets and
to apply particular queue handling or scheduling behavior
Appendix A Quality of Service
), and when the Router receives a packet from the
WAN
streams (
TCP
HTML
is, one must first be familiarized with the
DSCP
packet headers referred to as the Differentiated Services
IP
135
streams cannot be delayed)
UDP
ISP
traffic at the
. A solution for such a
ISP
connections (such as the file
TCP
) model that enhances
S
) is much
LAN
, which may not
. The
DSCP
DSCP
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