Table Of Contents
Mobile Networks Dynamic Collocated Care-of Address
Restrictions for Mobile Networks Dynamic CCoA
Information About Mobile Networks Dynamic CCoA
Mobile Networks Dynamic CCoA Feature Design
Benefits of Mobile Networks Dynamic CCoA
How to Configure Mobile Networks Dynamic CCoA
Enabling Dynamic CCoA Processing on a Mobile Router Interface
Enabling CCoA-Only Processing on a Mobile Router Interface
Verifying the Dynamic CCoA Configuration
Configuration Examples for Mobile Networks Dynamic CCoA
Mobile Networks Dynamic CCoA: Example
Mobile Networks with CCoA-Only Processing: Example
ip mobile router-service collocated
show ip mobile router interface
Mobile Networks Dynamic Collocated Care-of Address
Before the introduction of the Mobile Networks Dynamic Collocated Care-of Address feature, Cisco mobile networks supported foreign agent care-of address (CoA) registration and static collocated care-of address (CCoA) registration.
Static CCoA registration is considered a special case and applies to networks where the endpoint IP address is always fixed, such as in a Cellular Digital Packet Data (CDPD) wireless network. The Mobile Networks Static Collocated Care-of Address feature allows a mobile router with a static IP address to roam to foreign networks where foreign agents are not deployed.
The Mobile Networks Dynamic Care-of Address feature allows the mobile router to register with the home agent using a CCoA that is acquired dynamically via the IP Control Protocol (IPCP). Support for CCoAs acquired through the Dynamic Host Configuration Protocol (DHCP) is planned for a future release.
Feature History for the Mobile Networks Dynamic Collocated Care-of Address Feature
Finding Support Information for Platforms and Cisco IOS Software Images
Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at http://www.cisco.com/go/fn. You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions that appear.
Contents
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Restrictions for Mobile Networks Dynamic CCoA
•
Information About Mobile Networks Dynamic CCoA
•
How to Configure Mobile Networks Dynamic CCoA
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Configuration Examples for Mobile Networks Dynamic CCoA
Restrictions for Mobile Networks Dynamic CCoA
The Mobile Networks Dynamic CCoA feature can be configured only on serial (point-to-point) interfaces.
Information About Mobile Networks Dynamic CCoA
Before you configure the Mobile Networks Dynamic CCoA feature, you should understand the following concepts:
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Mobile Networks Dynamic CCoA Feature Design
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Benefits of Mobile Networks Dynamic CCoA
Care-of Addresses
If a mobile router determines that it is connected to a foreign network, it acquires a care-of address. This care-of address is the exit point of the tunnel from the home agent toward the mobile router. The care-of address is included in the Mobile IP registration request and is used by the home agent to forward packets to the mobile router in its current location. There are two types of care-of addresses:
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Care-of address acquired from a foreign agent
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Collocated care-of address
A foreign agent care-of address is an IP address on a foreign agent that is advertised on the foreign network being visited by a mobile router. A foreign agent CoA can be shared by other mobile routers. A collocated care-of address is an IP address assigned to the interface of the mobile router itself. A collocated care-of address represents the current position of the mobile router on the foreign network and can be used by only one mobile router at a time.
Mobile Networks Dynamic CCoA Feature Design
The Mobile Networks Dynamic CCoA feature is very similar to the static CCoA implementation. Static CCoA uses the address configured on the roaming interface as the CCoA. Dynamic CCoA uses IPCP to obtain a CCoA for the roaming interface. See the Cisco Mobile Networks - Static Collocated Care-of Address feature documentation for more information on the static CCoA implementation.
For both static and dynamic CCoA, the interface can be configured to exclusively use CCoAs for registration or to use a foreign agent CoA if one is available. In the foreign agent case, when an interface first comes up, it will attempt to discover foreign agents on the link by soliciting and listening for agent advertisements. If a foreign agent is found, the mobile router will register using the advertised CoA. The interface will continue to register using a CoA as long as a foreign agent is heard. When foreign agents are not heard, either because no advertisements are received or the foreign agent advertisement hold time expires, CCoA processing is enabled and the interface registers its CCoA. The CCoA is the interface's statically configured or dynamically acquired primary IP address. If a foreign agent is heard again, the interface will again register the foreign agent CoA.
You can configure the interface to register only its CCoA and ignore foreign agent advertisements by using the ip mobile router-service collocated ccoa-only option.
When the mobile router registers a CCoA with a home agent, a single HA-CCoA tunnel is created and is used for traffic to the mobile router and its mobile networks.
The CCoA configured on the mobile router interface will become the endpoint of the HA-CCoA tunnel as the home agent tunnels packets to the mobile router. The mobile router will use this same tunnel to reverse tunnel packets back to the home agent if configured for reverse tunnel.
Benefits of Mobile Networks Dynamic CCoA
This feature allows a mobile router to roam to foreign networks where foreign agents are not deployed and to obtain a CCoA dynamically through IPCP.
How to Configure Mobile Networks Dynamic CCoA
This section contains the following procedures:
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Enabling Dynamic CCoA Processing on a Mobile Router Interface (required)
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Enabling CCoA-Only Processing on a Mobile Router Interface (optional)
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Verifying the Dynamic CCoA Configuration (optional)
Enabling Dynamic CCoA Processing on a Mobile Router Interface
This task shows how to enable dynamic CCoA processing on a mobile router interface.
SUMMARY STEPS
1.
enable
2.
configure terminal
3.
interface type number
4.
ip address negotiated
5.
encapsulation ppp
6.
ip mobile router-service roam
7.
ip mobile router-service collocated
8.
ip mobile router-service collocated registration retry seconds
DETAILED STEPS
Enabling CCoA-Only Processing on a Mobile Router Interface
Perform this task to configure a mobile router interface to ignore foreign agent advertisements and exclusively use CCoAs for registration to the home agent. This functionality works for both static and dynamic CCoA processing.
SUMMARY STEPS
1.
enable
2.
configure terminal
3.
interface type number
4.
ip address ip-address mask
or
ip address negotiated5.
ip mobile router-service roam
6.
ip mobile router-service collocated ccoa-only
7.
ip mobile router-service collocated gateway ip-address ccoa-only
8.
ip mobile router-service collocated registration retry seconds
DETAILED STEPS
Verifying the Dynamic CCoA Configuration
Perform this task to verify the dynamic CCoA configuration:
SUMMARY STEPS
1.
show ip mobile router interface
2.
show ip mobile router agent
3.
show ip mobile router registration
4.
show ip mobile router
5.
show ip mobile binding
DETAILED STEPS
Configuration Examples for Mobile Networks Dynamic CCoA
This section provides the following configuration example:
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Mobile Networks Dynamic CCoA: Example
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Mobile Networks with CCoA-Only Processing: Example
Mobile Networks Dynamic CCoA: Example
The following example shows a mobile router configured to obtain a CCoA dynamically through IPCP:
interface loopback 0! MR home addressip address 10.1.0.1 255.255.255.255!! Dynamic CCoA.interface Serial 3/1ip address negotiatedencapsulation pppip mobile router-service roamip mobile router-service collocatedMobile Networks with CCoA-Only Processing: Example
The following example shows a mobile router configured to obtain a static CCoA only. The interface will not listen to foreign agent advertisements.
interface loopback1ip address 20.0.4.1 255.255.255.255!! Static CCoA with CCoA-only optioninterface Ethernet 1/0ip address 10.0.1.1 255.255.255.0ip mobile router-service roamip mobile router-service collocated gateway 10.0.1.2 ccoa-onlyip mobile router-service collocated registration retry 30The following example shows a mobile router configured to obtain a dynamic CCoA only. The interface will not listen to foreign agent advertisements.
interface loopback1ip address 20.0.4.1 255.255.255.255!! Dynamic CCoA with CCoA-only optioninterface Serial 2/0ip address negotiatedencapsulation pppip mobile router-service roamip mobile router-service collocated ccoa-onlyip mobile router-service collocated registration retry 30Additional References
The following sections provide additional references related to the Mobile Networks Dynamic CCoA feature.
Related Documents
Standards
Standards TitleNo new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.
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MIBs
RFCs
RFCs TitleNo new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature.
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Technical Assistance
Command Reference
This section documents modified commands. All other commands used with this feature are documented in the Cisco IOS Release 12.3 T command reference publications.
•
ip mobile router-service collocated
•
show ip mobile router interface
ip mobile router-service collocated
To enable static or dynamic collocated care-of address (CCoA) processing on a mobile router interface, use the ip mobile router-service collocated command in interface configuration mode. To disable static or dynamic CCoA processing, use the no form of this command.
ip mobile router-service collocated [gateway ip-address] [ccoa-only]
no ip mobile router-service collocated [gateway ip-address] [ccoa-only]
Syntax Description
Defaults
No default behavior or values
Command Modes
Interface configuration
Command History
Release Modification12.2(15)T
This command was introduced.
12.3(4)T
The ccoa-only keyword was added. Dynamic CCoA functionality was added.
Usage Guidelines
The primary IP address of the interface is used as the CCoA. The interface must already be configured as a roaming interface using the ip mobile router-service roam interface configuration command for both static and dynamic CCoA processing.
The mobile router can register with the home agent using a CCoA that was acquired dynamically via the IP Control Protocol (IPCP).
The gateway IP address is the next-hop IP address for registration packets. Upon successful registration, this address will be used as the default gateway and default route.
You need not specify the gateway ip-address combination if using a serial interface. The gateway ip-address combination is required on all non point-to-point interfaces such as Ethernet LANs and must be on the same logical subnet as the primary interface IP address.
You can configure the mobile router interface to register only its CCoA and ignore foreign agent advertisements by using the ip mobile router-service collocated ccoa-only option. Using this command on an interface already registered with a foreign agent CoA will cause the mobile router to re-register immediately with a CCoA.
Using the no ip mobile router-service collocated ccoa-only command on an interface already registered with a CCoA will cause the interface to deregister its CCoA and begin foreign agent discovery.
Examples
The following example enables static CCoA processing on a mobile router interface:
interface FastEthernet0/0! Primary IP address is the static CCoAip address 172.21.58.23 255.255.255.0ip mobile router-service roam! Gateway IP address is next-hop destinationip mobile router-service collocated gateway 172.21.58.1The following example enables dynamic CCoA processing on a mobile router interface:
interface Serial 3/1ip address negotiatedencapsulation pppip mobile router-service roamip mobile router-service collocatedThe following example enables static CCoA-only processing. The interface will not listen to foreign agent advertisements.
interface Ethernet 1/0ip address 10.0.1.1 255.255.255.0ip mobile router-service roamip mobile router-service collocated gateway 10.0.1.2 ccoa-onlyip mobile router-service collocated registration retry 30The following example enables dynamic CCoA-only processing. The interface will not listen to foreign agent advertisements.
interface Serial 1/0ip address negotiatedencapsulation pppip mobile router-service roamip mobile router-service collocated ccoa-onlyRelated Commands
show ip mobile router agent
To display information about the agents for the mobile router, use the show ip mobile router agent command in privileged EXEC mode.
show ip mobile router agent
Syntax Description
This command has no arguments or keywords.
Defaults
No default behavior or values.
Command Modes
Privileged EXEC
Command History
Usage Guidelines
This command displays a list containing information on all foreign agents currently discovered on the mobile router. This list also displays information about each interface configured for static or dynamic CCoA. An interface must be "up" to be displayed on the list.
You can use the clear ip mobile router agent command to clear foreign agent care-of addresses (CoAs) but not static CCoAs. CCoAs cannot be cleared.
Examples
The following is sample output from the show ip mobile router agent command when a CCoA is configured on a mobile router interface:
Router# show ip mobile router agentMobile Router Agents:Foreign agent 45.0.0.2:Care-of address 42.0.0.2Interface Ethernet1, MAC 0030.9492.6627Agent advertisement seq 56649, Flags rbhFmGvt, Lifetime 36000IRDP advertisement lifetime 30, Remaining 29Last received 02/13/02 17:55:48First heard 02/13/02 11:21:46Collocated Care-of address 48.0.0.1 (static):Interface Ethernet2Default gateway 48.0.0.2Registration retry interval 60Next CCoA reg attempt in 00:00:55 secondsCollocated Care-of address 11.0.0.7 (dynamic):Interface Serial0Registration retry interval 60Table 1 describes the significant fields shown in the display.
Related Commands
Command Descriptionclear ip mobile router agent
Deletes learned agents and the corresponding care-of address of the foreign agent from the mobile router agent table.
show ip mobile router interface
To display information about the interfaces configured for roaming, use the show ip mobile router interface command in privileged EXEC mode.
show ip mobile router interface
Syntax Description
This command has no arguments or keywords.
Defaults
No default behavior or values
Command Modes
Privileged EXEC
Command History
Usage Guidelines
The mobile router uses the interfaces for roaming, discovering foreign agents, and registering its location on the foreign network.
Use this command to display information about roaming interfaces. If the interface is configured for collocated care-of address (CCoA), the CCoA (IP address) is displayed. If it is not configured for a CCoA, "none" is displayed. The interface can be up or down.
Examples
The following is sample output from the show ip mobile router interface command. Ethernet interface 2 has no CCoA configuration, serial interface 0 has a static CCoA configuration, and serial interface 1 has a dynamic CCoA address, with CCoA only.
Router# show ip mobile router interfaceMobile Router Interfaces:Listed in order of preference.Ethernet2:Priority 102, Bandwidth 10000, Address 48.0.0.5Periodic solicitation disabled, Interval 600 secRetransmit Init 1000, Max 5000 msec, Limit 3Current 0, Remaining 0 msec, Count 0Hold down 0 secRouting disallowedCollocated CoA disabledSerial0:Priority 100, Bandwidth 1544, Address 11.0.0.7Periodic solicitation disabled, Interval 600 secRetransmit Init 1000, Max 5000 msec, Limit 3Current 1000, Remaining 0 msec, Count 1Hold down 0 secRouting disallowedCollocated CoA 11.0.0.7 (static)Serial1Priority 100, Bandwidth 1544, Address 10.0.0.5Periodic solicitation disabled, Interval 600 secRetransmit Init 1000, Max 5000 msec, Limit 3Current 0, Remaining 0 msec, Count 0Hold down 0 secRouting disallowedCollocated CoA 45.0.0.5 - Solicit FA firstTable 2 describes the significant fields shown in the display.
Related Commands
Command Descriptionip mobile router-service
Enables mobile router service on an interface.
ip mobile router-service collocated
Enables static or dynamic CCoA processing on a mobile router interface.
Glossary
care-of address—The termination point of the tunnel to a mobile node or mobile router. This can be a collocated care-of address, by which the mobile node or mobile router acquires a local address and detunnels its own packets, or a foreign agent care-of address, by which a foreign agent detunnels packets and forwards them to the mobile node or mobile router.
collocated care-of address—The termination point of a tunnel toward a mobile node or mobile router. A CCoA is a local address that the mobile node or mobile router associated with one of its own network interfaces.
foreign agent—A router on the visited network of a foreign network that provides routing services to the mobile node or mobile router while registered. The foreign agent detunnels and delivers packets to the mobile node or mobile router that were tunneled by the home agent of the mobile node. For packets sent by a mobile node, the foreign agent may serve as a default router for registered mobile nodes.
Note
Refer to Internetworking Terms and Acronyms for terms not included in this glossary.
Copyright © 2003 Cisco Systems, Inc. All rights reserved.

