User`s guide
Vigor2760 Series User’s Guide
65
4
4
.
.
1
1
.
.
7
7
.
.
2
2
D
D
N
N
S
S
S
S
e
e
t
t
t
t
i
i
n
n
g
g
This page is used to set the DNS server (including primary DNS and secondary DNS) that the
router will use.
Available parameters are listed below:
Item Description
Primary DNS
You must specify a DNS server IP address here because your
ISP should provide you with usually more than one DNS
Server. If your ISP does not provide it, the router will
automatically apply default DNS Server IP address:
198.95.1.1 to this field.
Secondary DNS
You can specify secondary DNS server IP address here
because your ISP often provides you more than one DNS
Server. If your ISP does not provide it, the router will
automatically apply default secondary DNS Server IP
address: 4.2.2.1 to this field.
Apply
Click it to save the settings.
Reset
Click it to retrieve the default settings of this page.
Refresh
Click it to refresh the web page.
After finished the settings above, click Apply to save the settings.
4
4
.
.
1
1
.
.
8
8
Q
Q
u
u
a
a
l
l
i
i
t
t
y
y
o
o
f
f
S
S
e
e
r
r
v
v
i
i
c
c
e
e
Service levels required and sufficient bandwidth to meet performance expectations is indeed
one important aspect of modern enterprise network.
One reason for QoS is that numerous TCP-based applications tend to continually increase their
transmission rate and consume all available bandwidth, which is called TCP slow start. If
other applications are not protected by QoS, it will detract much from their performance in the
overcrowded network. This is especially essential to those are low tolerant of loss, delay or
jitter (delay variation).
Another reason is due to congestions at network intersections where speeds of interconnected
circuits mismatch or traffic aggregates, packets will queue up and traffic can be throttled back
to a lower speed. If there’s no defined priority to specify which packets should be discarded
(or in another term “dropped”) from an overflowing queue, packets of sensitive applications
mentioned above might be the ones to drop off. How this will affect application performance?
There are two components within Primary configuration of QoS deployment: