In some deployments, it may be necessary to control which spectrum the cellular interface uses when it is searching for a cellular network to connect to. This can be achieved by configuring a list of cellular bands for each SIM using the command configure>card>mda>cellular>sim>band-list. See the 7705 SAR-Hm and SAR-Hmc Software Release Notes for information about the platforms that support cellular band selection.
The operator creates the band list by specifying the bands that are supported on the MDA. A total of four bands can be configured in the list: up to three LTE bands and one 3G band.
In a dual SIM deployment, a band list can be configured on one or both SIMs.
A SIM switchover causes the MDA to reset. If a band list is configured on the newly active SIM, the reset enables this band list. If the newly active SIM is not configured with a band list, the node uses the bands that are supported by the firmware.
If the list contains bands that are not supported by the firmware for a specific carrier, the node will use only the bands that are supported by the firmware. For example, if the firmware supports bands B2, B5, B7, B13, and B66 but the band-list is configured with bands B2, B42, B48, and B71, the node will only allow B2 to be configured on the MDA because it is the only band on the list that is supported by the firmware.
If none of the bands on the list are supported by the firmware, the node considers the band list to be misconfigured and ignores it. The node reverts to enabling all the bands supported by the firmware. Enabling all the supported bands ensures that the node can connect to the network if further actions are required to manage the node.
When a band list changes, the PDN interface goes down and attempts to reattach to the network. This may result in a brief data outage.
The output from the show mda 1/1 command provides information about the operational bands in use and whether the band list was applied or ignored. The command output also displays whether 3G is enabled or disabled.