Specifications

Engineering Guidelines
334
Standalone CXi, voice only
This is a self-contained configuration, with only the CXi unit involved in the network. There are
only voice devices connected to the CXi.
There is only a single device at each egress point of the Layer 2 switch, and so there are no
contention issues with data. There are also no data devices, so assigning priority to voice is
meaningless, since all voice devices will have equal priority. The network switch internal
bandwidth is in excess of the port capabilities, and much higher than the voice devices need
to handle. There is unlikely to be any throughput issues.
Connection to an expansion Layer 2 switch is also not an issue. Again the connection bandwidth
(Gig Ethernet) is in excess of that needed for the number of voice devices. Again VLAN and
priority settings will not provide benefit on this link.
In effect, for this configuration, there is no requirement for VLAN settings.
Physical segregation of voice and data networks
One method to maintain priority between voice and data networks is to operate these as two
independent networks. Although this may seem a little counter intuitive, it can be useful in
providing demarcation between the different services where different personnel look after
different parts of the network. The two networks are then joined at a higher level through a
router. The two “networks” would still need to be considered as a single system and IP addresses
assigned as appropriate.
From the voice side of the network this is very similar to the standalone case. The main
difference is a single connection to a router. This should be taken from the highest hierarchical
point in both voice and data networks.
Connection of the router allows various PC devices to gain access to services of the ICP
controller (CXi), if needed. For basic data operation, use of VLANs is unlikely to be needed,
since the bandwidth available at the CXi will be higher than the router connection.
The one exception to VLAN usage might be on the data side of the network where
MiCollab
Client
Softphones are in use. These devices are PC based, but are in effect voice devices. For
the
MiCollab Client Softphone, it is possible to queue data within the network, based on the value
of the DSCP/Type of service field. It may be necessary to implement VLAN within the data
section of the network in this case. The standard PC services will then take a VLAN and low
priority value. The voice applications will need to map the Type of service field to a VLAN priority,
to ensure correct priority queuing. All data from the PC will be in the same VLAN, just voice will
have a higher priority marking. The router will remove the VLAN information.
So, in general:
• VLAN is not needed in the voice portion of the network
• VLAN is not needed in the data portion of the network, except when
MiCollab Client Soft-
phones are in use.