Chapter 3: System planning
Data network planning
Page 3-34
Operators may configure priority precedence as 802.1p Then Diffserv (Default) or Diffserv Then
802.1p. Since these priority precedence configurations are independent between the AP and SM,
this setting must be configured on both the AP and SM to ensure that the precedence is adhered to
by both sides of the link.
VLAN settings can also cause the module to convert received non-VLAN packets into VLAN
packets. In this case, the 802.1p priority in packets leaving the module is set to the priority
established by the DiffServ configuration.
If VLAN is enabled, immediately monitor traffic to ensure that the results are as desired. For
example, high-priority traffic may block low-priority.
Q-in-Q DVLAN (Double-VLAN) Tagging (802.1ad)
PMP and PTP modules can be configured with 802.1ad Q-in-Q DVLAN (Double-VLAN) tagging
which is a way for an operator to put an 802.1Q VLAN inside of an 802.1ad VLAN. A nested VLAN,
which is the original 802.1Q tag and a new second 802.1ad tag, allows for bridging of VLAN traffic
across a network and segregates the broadcast domains of 802.1Q VLANs. Q-in-Q can be used
with PPPoE and/or NAT.
The 802.1ad standard defines the S-VLAN as the Service Provider VLAN and the C-VLAN as the
customer VLAN. The radio software does 2 layer Q-in-Q whereby the C-VLAN is the 802.1Q tag and
the S-VLAN is the second layer Q tag as shown in
Table 69
.
Table 69 Q-in-Q Ethernet frame
Ethernet Header
S-VLAN EthType
0x88a8
C-VLAN EthType
0x8100
IP Data EthType 0x0800
The 802.1ad S-VLAN is the outer VLAN that is configurable on the Configuration > VLAN web page
of the AP/BHM. The Q-in-Q EtherType parameter is configured with a default EtherType of 0x88a8
in addition to four alternate EtherTypes that can be configured to aid in interoperability with
existing networks that use a different EtherType than the default.
The C-VLAN is the inner VLAN tag, which is the same as 802.1Q. As a top level concept, this
operates on the outermost tag at any given time, either “pushing” a tag on or “popping” a tag off.
This means packets will at most transition from an 802.1Q frame to an 801.ad frame (with a tag
“pushed” on) or an untagged 802.1 frame (with the tag “popped” off. Similarly, for an 802.1ad
frame, this can only transition from an 802.1ad frame to an 802.1Q frame (with the tag “popped”
off) since the radio software only supports 2 levels of tags.
Содержание PMP 450d Series
Страница 101: ...Chapter 2 System hardware GPS synchronization Page 2 40 Figure 25 Cluster Management Scenario 1 ...
Страница 125: ...Chapter 3 System planning Typical deployment Page 3 3 Figure 37 Wall installation ...
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Страница 127: ...Chapter 3 System planning Typical deployment Page 3 5 Figure 39 GPS receiver wall installation ...
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