command: Home(config-if)#dialer-group 1 In
the command, group-number specifies the number of the
dialer group to which the interface belongs. The group number
can be an integer from 1 to 10. This number must match the
dialer-list group-number. Each interface can have
only one dialer group. However, the same dialer list can be
assigned to multiple interfaces with the dialer-group
command. The correct dialing information for the remote DDR
interface needs to be specified. This is done using the
dialer map command. The dialer map command maps
the remote protocol address to a telephone number. This command
is necessary to dial multiple sites.
Router(config-if)#dialer map protocol
next-hop-address [name hostname] [speed
56 | 64] [broadcast] dial-string If
dialing only one site, use an unconditional dialer
string command that always dials the one phone number
regardless of the traffic destination. This step is unique to
legacy DDR. Although the information is always required, the
steps to configure destination information are different when
using dialer profiles instead of legacy DDR. The dialer
idle-timeout seconds command may be used to specify
the number of idle seconds before a call is disconnected.
The seconds represent the number of seconds until a
call is disconnected after the last interesting packet is sent.
The default is 120. Web Links Configuration Examples
http://www.cisco.com/en/US/tech/tk801/
tk133/tech_configuration_ examples_list.html
Content
4.3 DDR Configuration 4.3.6
Dialer profiles Legacy DDR is limited because the configuration
is applied directly to a physical interface. Since the IP
address is applied directly to the interface, then only DDR
interfaces configured in that specific subnet can establish a
DDR connection with that interface. This means that there is a
one-to-one correspondence between the two DDR interfaces at
each end of the link. Dialer profiles remove the configuration
from the interface receiving or making calls and only bind the
configuration to the interface on a per-call basis. Dialer
profiles allow physical interfaces to dynamically take on
different characteristics based on incoming or outgoing call
requirements. Dialer profiles can do all of the following:
- Define encapsulation and access control lists
- Determine minimum or maximum calls
- Turn features
on or off
Dialer profiles aid in the design and
deployment of more complex and scalable circuit-switched
internetworks by implementing a more scalable DDR model in
Cisco routers and access servers. Dialer profiles separate the
logical portion of DDR, such as the network layer,
encapsulation, and dialer parameters, from the physical
interface that places or receives calls. Using dialer profiles,
the following tasks may be performed: - Configure B
channels of an ISDN interface with different IP subnets.
- Use different encapsulations on the B channels of an ISDN
interface.
- Set different DDR parameters for the B
channels of an ISDN interface.
- Eliminate the waste of
ISDN B channels by letting ISDN BRIs belong to multiple dialer
pools.
A dialer profile consists of the following
elements: - Dialer interface – A logical entity
that uses a per-destination dialer profile.
- Dialer
pool – Each dialer interface references a dialer pool,
which is a group of one or more physical interfaces associated
with a dialer profile.
- Physical interfaces –
Interfaces in a dialer pool are configured for encapsulation
parameters and to identify the dialer pools to which the
interface belongs. PPP authentication, encapsulation type, and
multilink PPP are all configured on the physical interface.
Like legacy DDR, dialer profiles activate when
interesting traffic is queued to be sent out a DDR interface.
First, an interesting packet is routed to a remote DDR IP
address. The router then checks the configured dialer
interfaces for one that shares the same subnet as the remote
DDR IP address. If one exists, the router looks for an unused
physical DDR interface in the dialer pool. The configuration
from the dialer profile is then applied to the interface and
the router attempts to create the DDR connection. When the
connection is terminated, the interface is returned to the
dialer pool for the next call. Web Links Dialer
Profiles http://www.cisco.com/en/US/tech/ tk801/tk133/tk159/
tech_protocol_home.html
Content 4.3 DDR
Configuration 4.3.7 Configuring dialer profiles
Multiple dialer interfaces may be configured on a router. Each
dialer interface is the complete configuration for a
destination. The interface dialer command creates a
dialer interface and enters interface configuration mode. To
configure the dialer interface, perform the following tasks:
- Configure one or more dialer interfaces with all the
basic DDR commands:
- IP address
- Encapsulation
type and authentication
- Idle-timer
- Dialer-group for interesting traffic
- Configure a dialer string and dialer
remote-name to specify the remote router name and phone
number to dial it. The dialer pool associates this
logical interface with a pool of physical interfaces.
- Configure the physical interfaces and assign them to a
dialer pool using the dialer pool-member command.
An interface can be assigned to multiple dialer pools by
using multiple dialer pool-member commands. If more than
one physical interface exists in the pool, use the
priority option of the dialer pool-member command
to set the priority of the interface within a dialer pool. If
multiple calls need to be placed and only one interface is
available, then the dialer pool with the highest priority is
the one that dials out. A combination of any of these
interfaces may be used with dialer pools: - Synchronous
Serial
- Asynchronous Serial
- BRI
- PRI
Lab Activity Lab Exercise:
Configuring Dialer Profiles In this lab, the student will
configure ISDN Dialer Profiles on the routers. Web
Links Dialer Profiles http://www.cisco.com/en/US/tech/
tk801/tk133/tk159/ tech_protocol_home.html
Content
4.3 DDR Configuration 4.3.8
Verifying DDR configuration The show dialer interface
[BRI] command displays information in the same format as
the legacy DDR statistics on incoming and outgoing calls. The
message “Dialer state is data link layer up” suggests that the
dialer came up properly and interface BRI 0/0:1 is bound to the
profile dialer1. The show isdn active command displays
information about the current active ISDN calls. In this
output, the ISDN call is outgoing to a remote router named
Seattle. The show isdn status command displays
information about the three layers of the BRI interface. In
this output, ISDN Layer 1 is active, ISDN Layer 2 is
established with SPID1 and SPID2 validated, and there is one
active connection on Layer 3. Web Links Configuration
Examples http://www.cisco.com/en/US/tech/
tk801/tk133/tech_configuration_
examples_list.html
Content 4.3 DDR Configuration
4.3.9 Troubleshooting the DDR configuration There are two
major types of DDR problems. Either a router is not dialing
when it should, or it is constantly dialing when it should not.
Several debug commands can be used to help troubleshoot
problems with a DDR configuration.The debug isdn q921
command is useful for viewing Layer 2 ISDN call setup
exchanges. The “i =” field in the Q.921 payload field is the
hexadecimal value of a Q.931 message. In the following lines,
the seventh and eighth most significant hexadecimal numbers in
the “i =” field indicate the type of Q.931 message:
- 0x05 indicates a call setup message
- 0x02
indicates a call proceeding message
- 0x07 indicates a