Beta Draft Confidential
12-21/19/05 ATM Services Configuration Guide for CBX 3500, CBX 500, GX 550, and B-STDX 9000
Configuring ATM Traffic Descriptors
Overview
Overview
Configuring a logical port associates ATM TDs with the logical port control channels.
Depending on the type of logical port, these control channels include ILMI, UNI
signaling, PNNI routing, trunk protocol, and management traffic control channels. To
simplify the provisioning process, you do not have to explicitly select the ATM TD
needed for the applicable control channel. A default value is always provided.
Table 12-5 (on page 12-13) through Table 12-7 (on page 12-15) describe these default
values in more detail.
In most cases, you do not need to change the control channel default TDs. However, if
you wish to have a particular control channel use a different QoS class or a different
peak cell rate (PCR), sustainable cell rate (SCR), or maximum burst size (MBS), you
have the ability to do so. For example, the default trunk signaling and management
control channels that are used on trunks between Lucent switches are assigned to use
the constant bit rate (CBR) QoS class and 5% of the configured logical port bandwidth
(2.5% for each of the two channels). If necessary, you can change the QoS class of the
trunk signaling channel; you can also change the amount of bandwidth associated with
it.
If you plan to change the default values for logical port control channels, follow these
guidelines:
• For control channels between two Lucent switches (which encompasses the trunk
signaling control channel and the node-to-node management traffic control
channel), the TD values (PCR/SCR/MBS) are only used to calculate the amount
of bandwidth reserved by the Connection Admission Control (CAC) for this type
of traffic. The TD values do not affect traffic shaping on these channels nor do
they affect the channel policing (these channels are never policed). You can
change the default amount of bandwidth reserved for these control channels if you
find the amount unacceptable.
• The default amount of control channel bandwidth reserved on OC-3c/STM1 and
OC-12c/STM4 trunks has changed. Previously, trunk control channel traffic was
reserved at 5% of the logical port bandwidth (regardless of the media type). In
some network scenarios for OC-3c/STM1 and OC-12c/STM4 trunks, this value
was excessive; see Table 12-7 on page 12-15 for new default reserved bandwidth
values.
• For control channels between a Lucent switch and another vendor device
(including the ILMI, UNI signaling, and PNNI routing control channels), the TD
values calculate both the amount of bandwidth reserved by CAC and the rate at
which the control channels are policed.
Control channels are not policed by default. You enable the usage parameter
control (UPC)/network parameter control (NPC) for the particular logical port,
and the control channel will be policed at the TD rate. Similar to the trunk control
channels, the TD values associated with the ILMI, UNI signaling, and PNNI
routing control channels do not affect the traffic shaping rate.
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