Cisco Mobile Networks Static Collocated Care-of Address
The Cisco Mobile Networks--Static Collocated Care-of Address feature allows a mobile router to roam to foreign networks where foreign agents are not deployed. Before the introduction of this feature, the mobile router was required to use a foreign agent care-of address when roaming. Now a roaming interface with a static IP address configured on the mobile router itself works as the collocated care-of address (CCoA).
Feature Specifications for Cisco Mobile Networks-Static Collocated Care-of Address
This feature was introduced.
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Prerequisites for Cisco Mobile Networks Static CCoA
Static CCoA applies to networks where the endpoint IP address is always fixed, such as in a Cellular Digital Packet Data (CDPD) wireless network.
Restrictions for Cisco Mobile Networks Static CCoA
Static CCoA is not recommended for environments where the endpoint IP address is not always fixed such as in the Dynamic Host Configuration Protocol (DHCP) or PPP/IPCP where the CCoA and gateway IP address are obtained dynamically.
Information About the Cisco Mobile Networks Static CCoA
If a mobile node or 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 towards the mobile node. 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 node in its current location. Two types of care-of addresses exist:
Care-of address acquired from a foreign agent
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 node. A mobile node that acquires this type of care-of address can share the address with other mobile nodes. A collocated care-of address is an IP address assigned to the interface of the mobile node itself. A collocated care-of address represents the current position of the mobile node on the foreign network and can be used by only one mobile node at a time.
For the Cisco Mobile Networks--Static CCoA feature, a static collocated care-of address is a fixed IP address configured on a roaming interface of the mobile router.
CCoA support using a dynamically acquired IP address will be available in a future release.
Benefits of Cisco Mobile Networks Static CCoA
This feature allows a mobile router to roam to foreign networks where foreign agents are not deployed.
Feature Design of Cisco Mobile Networks Static CCoA
In general, static CCoA is intended for links where there are no foreign agents. If foreign agents are present, the interface will not support foreign agent care-of address roaming while the interface is configured for static CCoA. Any foreign agent advertisements detected on that interface will be ignored. A static CCoA interface will solicit advertisements if configured but will not automatically solicit advertisements when the interface comes up. This behavior overrides the default behavior--typically, in the Cisco Mobile Networks feature, when an interface goes down and comes back up, foreign agent advertisements are solicited automatically.
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 static 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.
How to Configure Cisco Mobile Networks Static CCoA
Router(config-if)# ip mobile router-service collocated gateway 220.127.116.11
Enables static CCoA processing on a mobile router.
The gateway IP address is the next hop IP address for the mobile router to forward packets. The gateway IP address is required only on Ethernet interfaces, and must be on the same logical subnet as the primary interface address specified in Step 4.
The following example shows a mobile router configured with a static CCoA address of 172.21.58.23 and a next-hop gateway address of 172.21.58.1.
interface loopback 0
! MR home address
ip address 10.1.0.1 255.255.255.255
ip address 172.21.58.23 255.255.255.0
ip mobile router-service roam
ip mobile router-service collocated gateway 172.21.58.1
ip mobile router-service collocated registration retry 3
ip mobile router
address 10.1.0.1 255.255.255.255
ip mobile secure home-agent 18.104.22.168 spi 100 key hex 12345678123456781234567812345678
For additional information related to Cisco Mobile Networks--Static Collocated Care-of Address, see the following references:
Mobile IP configuration tasks
"Configuring Mobile IP" chapter in the
Cisco IOS IP Configuration Guide, Release 12.2
Mobile IP commands: complete command syntax, command mode, defaults, usage guidelines, and examples
"Mobile IP Commands" chapter in theCisco IOS IP Command Reference, Volume 1 of 3: Addressing and Services,
Mobile IP commands related to Cisco Mobile Networks
"Cisco Mobile Networks" feature document, Release 12.2(4)T and 12.2(13)T
No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.
No new or modified MIBs are supported by this feature, and support for existing MIBs has not been modified by this feature.
To obtain lists of supported MIBs by platform and Cisco IOS release, and to download MIB modules, go to the Cisco MIB website on Cisco.com at the following URL:
No 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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The following commands are introduced or modified in the feature or features documented in this module. For information about these commands, see the
Cisco IOS IP Mobility Command Reference at http://www.cisco.com/en/US/docs/ios/ipmobility/command/reference/imo_book.html. For information about all Cisco IOS commands, go to the Command Lookup Tool at
http://tools.cisco.com/Support/CLILookup or to the
Cisco IOS Master Commands List .
care-ofaddress--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.
foreignagent--A router on the visited network of a foreign network that provides routing services to the mobile node 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.
link--A facility or medium over which mobile nodes communicate at the link layer. A link underlies the network layer.