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The Cisco MC3810 multiservice access concentrator supports different PBX signaling formats. Depending on the PBX and the configuration, you can configure the Cisco MC3810 to support Channel Associated Signaling (CAS), Q.SIG PRI, or transparent Common Channel Signaling (CCS).
This chapter is divided into the following sections:
To configure the T1/E1 line to support CAS for voice traffic, complete the following steps in controller configuration mode:
| Step | Command | Purpose |
|---|---|---|
1 | router(config-controller)# mode cas | Configure the T1/E1 line to support CAS. |
2 | router(config-controller-
cas)# voice-group channel-no
timeslots timeslot-listtype
{e&m-immediate | e&m-delay |
e&m-wink| e&m-melcas |
fxs-ground-start |
fxs-loop-start | fxs-melcas |
fxo-ground-start |
fxo-loop-start | fxo-melcas)
|
When configuring a CAS group for a T1/E1 line to a PBX, make sure the channel numbers configured match the channels on the PBX. Contact the PBX administrator to determine which channels to use. |
3 | Repeat step 2 for each CAS group defined. | |
For CAS, you can also define the bit pattern for the seize and idle signals in both inbound and outbound directions on a voice port. To configure voice ports for this operation, perform the following tasks in voice-port configuration mode:
| Step | Command | Purpose |
|---|---|---|
1 | router(config-voiceport)#
define {Tx-bits | Rx-bits}
{seize | idle} {0000 | 0001 |
0010 | 0011 | 0100 | 0101 | 0110
| 0111 | 1000 | 1001 | 1010 |
1011 | 1100 | 1101 | 1110 |
1111}
|
E&M interfaces use two-state signaling, in which the interface is in either seize or idle state for both transmit and receive. The define command allows the seize and idle patterns to be customized. Note Be careful not to define invalid configurations, such as all 0000 on E1, or identical seize and idle states. |
2 | router(config-voiceport)#
ignore {rx-a-bit | rx-b-bit |
rx-c-bit | rx-d-bit}
| Configure the voice port to ignore specific receive bits. The ignore command customizes the receive pattern for determining the seize and idle state. |
This completes the CAS configuration.
The following restrictions and limitations apply to the Cisco MC3810 Q.SIG PRI implementation:
Figure 11-1 shows an example of a Q.SIG signaling configuration. In the example, the Cisco MC3810 either acts as a master to a slave PBX, or as a slave to a master PBX.
To configure Q.SIG PRI signaling support, complete the following steps beginning in global configuration mode:
| Step | Command | Purpose |
|---|---|---|
1 | router(config)# isdn switch-type [primary-qsig-slave | primary-qsig-master] | Configure the ISDN switch type to serve either as the primary Q.SIG slave or the primary Q.SIG master. If the PINX is the primary Q.SIG master, configure the Cisco MC3810 to serve as the primary Q.SIG slave. If the PINX is the primary Q.SIG slave, configure the Cisco MC3810 to serve as the primary Q.SIG master. Note You can configure the ISDN switch type using either this global command, or this same command in interface configuration mode, depending on your configuration. (See step 3.) If you configure the global isdn-switch-type command for Q.SIG support, you do not need to also configure the interface isdn-switch-type command for Q.SIG.For more information about the different options available with this command at the global and interface configuration level, see the "ISDN Switch Type Command Options" section. |
2 | router(config)# interface serial 1:x | Enter interface configuration mode for the ISDN PRI interface. For T1, enter serial 1:23. For E1, enter serial 1:15. |
3 | router(config-if)# | If you did not configure the global ISDN switch type for Q.SIG support in step 1, configure the interface ISDN switch type to serve either as the primary Q.SIG slave or the primary Q.SIG master. The same conditions that apply to this command in global configuration mode also apply to this command in interface configuration mode. Note This interface command overrides the global isdn switch-type command setting for this interface. |
4 | router(config-if)# isdn overlap-receiving value | |
5 | router(config-if)# isdn network-failure-cause [1-127] | |
6 | router(config-if)# isdn
bchan-number-order {ascending |
descending}
| (Optional) Configure the ISDN Primary Rate Interface (PRI) interface to make the outgoing call selection in ascending or descending order. The default is descending order, in which the first call from the Cisco MC3810 uses channel 23 (T1) or channel 31 (E1). The second call then uses channel 22 (T1) or channel 30 (E1), and so on in descending order. If you select ascending order and the PRI group starts with 1, the first call uses channel 1, the second call uses channel 2, and so on in ascending order. If the PRI group starts with a different timeslot, the ascending order starts with the lowest timeslot. |
7 | router(config)#
controller
{T1|E1} 1
| Enter controller configuration mode. Q.SIG is only supported on controller 1. |
8 | router(config-controller) # pri-group timeslot [1-31] |
You can configure the PRI group to include all the timeslots available, or you can configure a select group of timeslots for the PRI group. For example, if only timeslots 1-10 are in the PRI group, enter pri-group timeslot 1-10. If the PRI group includes all channels available for T1, enter pri-group timeslot 1-24. If the PRI group includes all channels available for E1, enter pri-group timeslot 1-31. Note When a PRI group is configured, T1 timeslot 24 or E1 timeslot 16 is automatically assigned to handle D-channel signaling. |
As shown in the procedure, you have a choice of configuring the isdn-switch-type command to support Q.SIG at either the global configuration level or at the interface configuration level. For example, if you have a Q.SIG connection on one line as well as on the BRI port, you can configure the ISDN switch type in one of the following combinations:
When voice dial peers are configured for use with Q.SIG PRI, voice port 1/1 is used for all bearer channels.
You may need to configure voice dial peers to specify destination patterns for routing calls. For more information, refer to "Configuring Voice over Frame Relay," "Configuring Voice over ATM," or "Configuring Voice over HDLC," depending on your configuration.
You can configure transparent CCS in one of two ways: CCS cross-connect (or TDM cross-connect, which implies a fractional trunk), or CCS frame-forwarding. These procedures are described in the following sections:
This section is divided into the following procedures:
Figure 11-2 shows an example of CCS cross-connect. In this example, the CCS channel from the PBX is cross-connected on the Cisco MC3810 to a timeslot on the T1/E1 controller. The channel is then passed through the WAN as a leased line to the second Cisco MC3810, where it is cross-connected to the digital voice module (DVM) signaling timeslot (timeslot 24 for T1, or timeslot 16 for E1). The channel is then passed to the second PBX. The CCS signal byte stream is passed through transparently by the Cisco MC3810.
| Step | Command | Purpose |
|---|---|---|
1 | router(config)# controller T1 0 | Enter controller configuration mode for controller T1 0. |
2 | router(config-controller)# tdm-group tdm-group-no timeslot timeslot-list | Configure a TDM channel group for controller T1 0. Do not specify the type option in the command.
|
3 | router(config)# controller T1 1 | Enter controller configuration mode for controller T1 1. |
4 | router(config-controller)# mode ccs cross-connect | Configure CCS cross-connect for controller T1 1. |
5 | router(config-controller)# tdm-group tdm-group-no timeslot timeslot-list | Configure a TDM channel group for controller T1 1. Do not specify the type option in the command. |
6 | router(config)# cross-connect id controller-1 tdm-group-no-1 controller-2 tdm-group-no-2 | Configure cross-connect pass-through between the two controllers. |
To configure CCS cross-connect for E1, complete the following steps beginning in global configuration mode:
| Step | Command | Purpose |
|---|---|---|
1 | router(config)# controller E1 0 | Enter controller configuration mode for controller E1 0. |
2 | router(config-controller)# tdm-group tdm-group-no timeslot timeslot-list | Configure a TDM channel group for E1. Do not specify the type option in the command. |
3 | router(config)# controller E1 1 | Enter controller configuration mode for controller E1 1. |
4 | router(config-controller)# mode ccs cross-connect | |
5 | router(config-controller-cas)# voice-group channel-no timeslots timeslot-list type [ext-sig-master | ext-sig-slave] | Configure the specified channel to support CCS mode, and specify whether the T1/E1 trunk will be the external signaling master or slave. A channel configured as ext-sig-master automatically generates the off-hook signal and stays in the off-hook state. A channel configured as ext-sig-slave automatically generates the answer signal when a call is terminated to that channel. These type options are available only when the mode ccs command is enabled. |
6 | router(config)# cross-connect id controller-1 tdm-group-no-1 controller-2 tdm-group-no-2 | Configure cross-connect pass-through between the two controllers. |
If you will use CCS cross-connect for bearer channels of the T1/E1 trunk, you will need to perform some additional configuration. To configure the T1/E1 trunk to support CCS cross-connect for bearer channels, complete the following steps beginning in global configuration mode:
| Step | Command | Purpose |
|---|---|---|
1 | router(config)# controller | Enter controller configuration mode for the controller. |
2 | router(config-controller) # mode ccs cross-connect | Specify the controller to support CCS cross-connect. |
3 | router(config-controller- cas)# voice-group channel-no timeslots timeslot-list type [ext-sig-master | ext-sig-slave] | Configure the specified channel to support CCS mode, and specify whether the T1/E1 trunk will be the external signaling master or slave. A channel configured as ext-sig-master automatically generates the off-hook signal and stays in the off-hook state. A channel configured as ext-sig-slave automatically generates the answer signal when a call is terminated to that channel. These type options are available only when the mode ccs command is enabled. |
4 | router(config)# voice-port slot/port | Enter voice-port configuration mode. For digital voice ports, the slot number is 1 for this configuration. Valid numbers for port are 1-24 for T1, and 1-15 and 17-31 for E1. For more detailed information on how to configure voice ports, see "Configuring Voice Ports." |
5 | router(config-voiceport)# connection plar string | Configure the voice-port connection to support Private Line Auto Ringdown (PLAR) mode. For the string, enter the number of the voice channel that was configured as the ext-sig-slave for the voice-group command. Note After a transparent CCS connection is configured by entering the connection plar command, any change to the configuration will not take place until the connection is shut down with a shutdown command and then restarted with a no shutdown command. For example, the phone number supplied in the connection plar command can be changed while the connection is in no shutdown state, but the change will not cause the current connection to be closed and a new connection opened to the new phone number. This will only take effect on the next no shutdown command after a shutdown command. |
The voice channel type configured as the ext-sig-master is considered the master side of the permanent virtual circuit (PVC) connection and is responsible for establishing the PVC connection. After the master channel is configured, a fixed timer of 30 seconds starts. The voice signaling driver then generates an off-hook signal on the master voice channel after the timer expires. The call is treated as a regular call, and the master voice channel will not hang up after the connection is made. If the call does not go through, or if the T1/E1 trunk is down, the 30-second timer on the master channel side restarts. A new off-hook signal is then generated at the master channel side after the timer expires.
CCS cross-connect is not supported on analog PVC connections.
With CCS frame-forwarding, the connection between PTNXs over the network must be point-to-point and preconfigured. With the CCS frame-forwarding implementation, calls from the PTNXs are not routed, but follow a preconfigured route to the destination.
Figure 11-3 shows an example of CCS frame-forwarding. In the example, the Cisco MC3810 captures the signaling frame from the PBX. The Cisco MC3810 then transports the signaling frame as a data frame through the Frame Relay or ATM network to the second Cisco MC3810. The second Cisco MC3810 then forwards the signaling frame to the PBX signaling channel.
To configure CCS frame-forwarding, complete the following steps beginning in global configuration mode:
| Step | Command | Purpose |
|---|---|---|
1 | router(config)# controller | Enter controller configuration mode. CCS frame-forwarding is only available on controller T1/E1 1. |
2 | router(config-controller) # mode ccs frame-forwarding | Specify the controller to support CCS transparent signaling. |
3 | router(config-controller- cas)# voice-group channel-no timeslots timeslot-list type [ext-sig-master | ext-sig-slave] | Configure the specified channel to support CCS mode, and specify whether the T1/E1 trunk will be the external signaling master or slave. A channel configured as ext-sig-master automatically generates the off-hook signal and stays in the off-hook state. A channel configured as ext-sig-slave automatically generates the answer signal when a call is terminated to that channel. These type options are available only when the mode ccs command is enabled. |
4 | router(config)# voice-port slot/port | Enter voice-port configuration mode. For digital voice ports, the slot number is always 1. Valid numbers for port are 1-24 for T1, and 1-15 and 17-31 for E1. For more detailed information on how to configure voice ports, see "Configuring Voice Ports." |
5 | router(config-voiceport)# connection plar string | If the voice port in the voice group is configured as the ext-sig-master, configure the voice-port connection to support PLAR mode for bearer channels. For the string, enter the number of the voice channel that was configured as the ext-sig-master for the voice-group command. If the voice port in the voice group is configured as the ext-sig-slave, the dial peer should just terminate the PLAR calls. Note After a transparent CCS connection is configured by entering the connection plar command, any change to the configuration will not take place until the connection is shut down with a shutdown command and then restarted with a no shutdown command. For example, the phone number supplied in the connection plar command can be changed while the connection is in no shutdown state, but the change will not cause the current connection to be closed and a new connection opened to the new phone number. This will only take effect on the next no shutdown command after a shutdown command. |
6 | router(config)# interface serial 1:x | Enter interface mode for serial 1:x where x represents the channel number. For E1, enter 15. For T1, enter 23. This procedure maps the D channel from the DVM to the specified interface. |
7 | router(config-if)# ccs
connect {serial |atm} number
[dlcidlci| pvc vci | pvc vcd |
pvcvpi/vci | pvc string]
| |
8 | router(config-if)# no cdp enable | Disable Cisco Discovery Protocol (CDP) on the interface. |
9 | router(config-if)# no keepalive | Disable keepalive packets on the interface. |
Posted: Tue Apr 27 13:14:16 PDT 1999
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