Configuring a Dialer Interface for USB Modem Dial Backup

Branch Office

1. Configure the logical dialer interface on the branch office router for USB modem dial backup.
2. Configure the dialer interface dl0 in one of the following ways on the branch office router:
   • Configure the dialer interface dl0 as the backup interface on the branch office router's primary T1 interface t1-1/0/0.
   • Configure a dialer filter on the branch office router's dialer interface.
   • Configure a dialer watch on the branch office router's dialer interface.

• To configure the logical dialer interface, see Table 78.
• To configure dl0 as a backup for t1-1/0/0 see Configuring Dial Backup for a USB Modem Connection.
• To configure a dialer filter on dl0, see Configuring a Dialer Filter for USB Modem Dial Backup.
• To configure a dialer watch on dl0, see Configuring Dialer Watch for USB Modem Dial Backup.

Head Office

Configure dial-in on the dialer interface dl0 on the head office router.

To configure dial-in on the head office router, see Configuring Dial-In for a USB Modem Connection.

Navigate to the Interfaces level in the configuration hierarchy.

1. In the J-Web interface, select Configuration>Edit Configuration>View and Edit.
2. Next to Interfaces, click Configure or Edit.

From the [edit] hierarchy level, enter

edit interfaces

Create the new interface—for example, dl0.

Adding a description can differentiate between different dialer interfaces—for example, USB-modem-backup.

1. Next to Interface, click Add new entry.
2. In the Interface name box, type dl0.
3. In the Description box, type USB-modem-backup.
4. Click OK.

Create and name the interface:

1. edit dl0
2. set description USB-modem-backup

Configure Point-to-Point Protocol (PPP) encapsulation.

Note: You cannot configure Cisco High-Level Data Link Control (HDLC) or Multilink PPP (MLPPP) encapsulation on dialer interfaces used in USB modem connections.

1. In the Encapsulation column, next to the new interface, click Edit.
2. From the Encapsulation list, select ppp.

Enter

set encapsulation ppp

Create the logical unit 0.

Note: You can set the logical unit to 0 only.

1. Next to Unit, click Add new entry.
2. In the Interface unit number box, type 0.
3. Next to Dialer options, select Yes, and then click Configure.

Enter

set unit 0

Configure dialer options.

• Activation delay—Number of seconds to wait before activating the backup USB modem interface after the primary interface is down—for example, 30. The default value is 0 seconds, and the maximum value is 60 seconds. Use this option only for dialer backup and dialer watch.
• Deactivation delay—Number of seconds to wait before deactivating the backup USB modem interface after the primary interface is up—for example, 30. The default value is 0 seconds, and the maximum value is 60 seconds. Use this option only for dialer backup and dialer watch.
• Idle timeout—Number of seconds a connection is idle before disconnecting—for example, 30. The default value is 120 seconds, and the range is from 0 to 4294967295.
• Initial route check—Number of seconds to wait before checking if the primary interface is up—for example, 30. The default value is 120 seconds, and the range is from 1 to 300 seconds.
• Pool—Name of the dialer pool to use for USB modem connectivity—for example, usb-modem-dialer-pool.

1. In the Activation delay box, type 60.
2. In the Deactivation delay box, type 30.
3. In the Idle timeout box, type 30.
4. In the Initial route check box, type 30.
5. In the Pool box, type usb-modem-dialer-pool.

1. Enter

   edit unit 0 dialer-options

2. Enter

   set activation-delay 60

3. Enter

   set deactivation-delay 30

4. Enter

   set idle-timeout 30 initial-route-check 30 pool usb-modem-dialer-pool

Configure the telephone number of the remote destination to call if the primary interface goes down—for example, 5551212.

1. Next to Dial string, click Add new entry.
2. In the Dial string box, type 5551212.
3. Click OK.

Enter

set dial-string 5551212

Configure source and destination IP addresses for the dialer interface—for example, 172.20.10.2 and 172.20.10.1.

Note: If you configure multiple dialer interfaces, ensure that the same IP subnet address is not configured on different dialer interfaces. Configuring the same IP subnet address on multiple dialer interfaces can result in inconsistency in the route and packet loss. Packets can be routed through any of the dialer interfaces with the IP subnet address, instead of being routed through the dialer interface to which the USB modem call is mapped.

1. Select Inet under Family, and click Edit.
2. Next to Address, click Add new entry.
3. In the Source box, type 172.20.10.2.
4. In the Destination box, type 172.20.10.1.
5. Click OK.

1. From the [edit] hierarchy level, enter

   edit interfaces dl0 unit 0

2. Enter

   set family inet address 172.20.10.2 destination 172.20.10.1

Navigate to the Interfaces level in the configuration hierarchy.

1. In the J-Web interface, select Configuration>Edit Configuration>View and Edit.
2. Next to Interfaces, click Edit.

From the [edit] hierarchy level, enter

edit interfaces t1-1/0/0 unit 0

Select the physical interface for USB modem USB modem backup connectivity—for example, t1–1/0/0.

1. In the Interface name column, click the physical interface name.
2. Under Unit, in the Interface unit number column, click 0.

Configure the backup dialer interface—for instance, dl0.0.

1. Next to Backup options, click Configure.
2. In the Interface box, type dl0.0.
3. Click OK until you return to the Interfaces page.

Enter

set backup-options interface dl0.0

Navigate to the Firewall level in the configuration hierarchy.

1. In the J-Web interface, select Configuration>Edit Configuration>View and Edit.
2. Next to Firewall, click Edit.

From the [edit] hierarchy level, enter

edit firewall

Configure the dialer filter name—for example, interesting-traffic.

1. Next to Inet, click Configure or Edit.
2. Next to Dialer filter, click Add new entry.
3. In the Filter name box, type interesting-traffic.

1. Enter

   edit family inet

2. Then enter

   edit dialer-filter interesting-traffic

Configure the dialer filter rule name—for example, term1.

Configure term behavior. For example, you might want to configure the dialer filter to allow only traffic between the TGM550 gateway module installed in the Services Router and the Media Gateway Controller (MGC) over the backup USB modem connection. In this example, the TGM550 has the IP address 20.20.90.4/32 and the MGC has the IP address 200.200.201.1/32.

To configure the term completely, include both from and then statements.

1. Next to Term, click Add new entry.
2. In the Rule name box, type term1.
3. Next to From, click Configure.
4. Next to Source address, click Add new entry.
5. In the Address box, type 20.20.90.4/32.
6. Click OK.
7. Next to Destination address, click Add new entry.
8. In the Address box, type 200.200.201.1/32.
9. Click OK until you return to the Term page.

1. Enter

   edit term term1

2. Enter

   set from source-address 20.20.90.4/32

3. Enter

   set from destination-address 200.200.201.1/32

Configure the then part of the dialer filter to discard Telnet traffic between the TGM550 and the MGC.

1. Next to Then, click Configure.
2. From the Designation list, select Note.
3. Click OK.

Enter

set then note

Navigate to the Interfaces level in the configuration hierarchy.

1. In the J-Web interface, select Configuration>Edit Configuration>View and Edit.
2. Next to Interfaces, click Edit.

From the [edit] hierarchy level, enter

edit interfaces dl0 unit 0

Select the dialer interface to apply the filter—for example, dl0.

1. In the Interface name column, click dl0.
2. Under Unit, in the Interface unit number column, click 0.

Apply the dialer filter to the dialer interface.

1. In the Family section, next to Inet, click Edit.
2. Next to Filter, click Configure.
3. In the Dialer box, type interesting-traffic, the dialer filter configured in Configuring the Dialer Filter.
4. Click OK.

1. Enter

   edit family inet filter

2. Enter

   set dialer interesting-traffic

Navigate to the Interfaces level in the configuration hierarchy.

1. In the J-Web interface, select Configuration>Edit Configuration>View and Edit.
2. Next to Interfaces, click Edit.

From the [edit] hierarchy level, enter

edit interfaces

Select a dialer interface—for example, dl0.

Adding a description, such as dialer-watch, can help you identify one dialer interface from another.

1. Under Interface name, select dl0.
2. In the Description box, type dialer-watch.

1. Enter

   edit dl0

2. Enter

   set description dialer-watch

On a logical interface—for example, 0—configure the route to the MGC for dialer watch—for example, 200.200.201.1/32.

1. Under Unit, click the logical unit number 0.
2. Next to Dialer options, click Edit.
3. Next to Watch list, click Add new entry.
4. In the Prefix box, type 200.200.201.1/32.
5. Click OK.

1. Enter

   edit unit 0 dialer-options

2. Enter

   set watch-list 200.200.201.1/32

Configure the name of the dialer pool to use for dialer watch—for example, dw-pool.

1. In the Pool box, type dw-pool.
2. Click OK.

Enter

set pool dw-pool

Navigate to the Interfaces level in the configuration hierarchy, and select the USB modem physical interface umd0.

1. In the J-Web interface, select Configuration>Edit Configuration>View and Edit.
2. Next to Interfaces, click Edit.
3. Under Interface name, click umd0.

From the [edit] hierarchy level, enter

edit interfaces umd0 dialer-options pool dw-pool

Configure dialer watch options for the USB modem interface participating in the dialer watch.

The USB modem interface must have the same pool identifier to participate in dialer watch. Therefore, the dialer pool name dw-pool, for the dialer watch interface configured in Table 82, is used when configuring the USB modem interface.

1. Next to Dialer options, click Edit.
2. Next to Pool, click Add new entry.
3. In the Pool identifier box, type dw-pool.
4. Click OK.