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Configuring Channelized DS3-to-DS1 Interfaces


You can configure 28 T1 channels per T3 interface, and each interface can have logical interfaces. To specify the channel number, include it after the colon (:) in the interface name. For example, a 4-port T3 PIC in FPC 1 and slot 1 will have the following physical interfaces, depending on the media type:

where x is a channel number ranging from 0 through 27.

To configure channelized DS3-to-DS1 interface properties, you can include both the t1-options and t3-options statements. Only a subset of the T3 options is valid for this configuration, and the buildout, invert-data, and line-encoding statements at the [edit interfaces interface-name t1-options] hierarchy level are ignored. Likewise, only a subset of the DS0 options are valid for this configuration, and the bert-algorithm, bert-error-rate, bert-period, and loopback payload statements at the [edit interfaces interface-name ds0-options] hierarchy level are ignored. The following configuration lists all the valid parameters.

To specify options for the T3 side of the connection, include the t3-options statement at the [edit interfaces interface-name] hierarchy level:

The statements in the t3-options hierarchy are supported only for channel 0; they are ignored if configured on other channels.

To specify options for each of the T1 channels, include the t1-options statement at the [edit interfaces interface-name] hierarchy level:

For T1 channels on a channelized T3 interface, the clocking statement is supported only for channel 0; it is ignored if included in the configuration of channels 1 through 11. The clock source configured for channel 0 applies to all channels on the channelized T3 interface. The individual T1 channels use a gapped 45-MHz clock as the transmit clock. When you configure the clock source for a channelized interface—ds-fpc/pic/port :0, for example—you must also include the channel-group statement at the [edit chassis] hierarchy level, and specify channel group 0. For more information, see Clock Sources on Channelized Interfaces.

For information about Frame Relay DLCI limitations for channelized interfaces, see Data-Link Connection Identifiers on Channelized Interfaces. For more information about Frame Relay DLCIs, see Configuring Frame Relay DLCIs. For more information about DLCI sparse mode, see the Junos OS Administration Library.

For more information about specific parameters, see T1 Interfaces Overview and T3 Interfaces Overview. For a configuration example, see Examples: Configuring Channelized DS3-to-DS1 Interfaces.