Table Of Contents
Cisco Mobile Networks—Priority HA Assignment
Information About Cisco Mobile Networks—Priority HA Assignment
Feature Design of Cisco Mobile Networks—Priority HA Assignment
Benefits of Cisco Mobile Networks—Priority HA Assignment
How to Configure Cisco Mobile Networks—Priority HA Assignment
Configuring Care-of Address Access Lists on an HA
Configuring HA Priorities on the Mobile Router
Configuration Examples for Cisco Mobile Networks—Priority HA Assignment
HA Priority Configuration Example
Cisco Mobile Networks—Priority HA Assignment
Before the introduction of the Cisco Mobile Networks—Priority HA Assignment feature, the mobile router preconfigured home agents (HAs) with different priorities, registering with only the highest priority home agent. However, a mobile router may roam to an area where registration with a closer home agent is more desirable. This feature allows a mobile router to register with the closer home agent using the combination of existing home agent priority configurations on the mobile router and care-of address access lists configured on the home agent.
Feature Specifications for the Cisco Mobile Networks—Priority HA Assignment Feature
12.2(15)T
This feature was introduced.
For information about platforms supported, refer to Cisco Feature Navigator.
Finding Support Information for Platforms and Cisco IOS Software Images
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Contents
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Information About Cisco Mobile Networks—Priority HA Assignment
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Information About Cisco Mobile Networks—Priority HA Assignment
Before you configure the Cisco Mobile Networks—Priority HA Assignment feature, you should understand the following concepts:
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Feature Design of Cisco Mobile Networks—Priority HA Assignment
Benefits of Cisco Mobile Networks—Priority HA Assignment
This feature allows a mobile router to register with a geographically closer HA, which improves latency on the network.
How to Configure Cisco Mobile Networks—Priority HA Assignment
This section includes the following procedures:
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Configuring Care-of Address Access Lists on an HA
This task describes how to configure care-of address access lists on an HA.
Best HA Selection Process
If more than one HA is reachable from any care-of address that may be used by the mobile router, then the HAs need an access list (which is a foreign agent care-of address or collocated care-of address) configured to enforce the best HA selection process. This configuration enforces a region covered by a specific HA defined by the care-of addresses (configured as access lists) within the region. Registrations originating outside the region are administratively denied while registrations within the region are processed.
Restrictions
Without the distribute-list command configured, each HA will advertise a route to the same virtual network. This situation may cause routing conflicts and traffic destined to the home network of the mobile router to be dropped.
With the distribute-list command configured, you can suppress the advertisement of the virtual networks to the rest of the network. However, pings to the mobile router home address will fail but pings to an address with the mobile network served by the mobile router will succeed. Traffic destined to the mobile network would continue to reach the destination without problems.
If the home network consists of both mobile routers and mobile nodes, the distribute-list command will block only the addresses of the mobile routers and not the entire subnet.
Routes to the mobile router are not advertised when the mobile router is not registered. Pings to an address on the mobile network will return unreachable if the mobile router is not registered.
Mobile networks will only be advertised by one HA at a time as long as deregistration to the old HA is successful. After roaming to a new HA, pings to the mobile network may take some time depending on how fast the mobile network route is propagated throughout the network by the routing protocol.
SUMMARY STEPS
1.
2.
3.
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6.
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8.
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10.
11.
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13.
14.
DETAILED STEPS
Step 1
enable
Example:Router> enable
Enables privileged EXEC mode.
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Step 2
configure terminal
Example:Router# configure terminal
Enters global configuration mode.
Step 3
ip mobile home-agent care-of-access access-list
Example:Router(config)# ip mobile home-agent care-of-access HA1-FA1
Controls which care-of addresses in registration requests are permitted by the home agent.
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Step 4
ip access-list standard access-list-name
Example:Router(config)# ip access-list standard HA1-FA1
Defines a standard access list and enters standard named access list configuration mode.
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Step 5
permit coa-ip-address
Example:Router(config-std-nacl)# permit 3.3.3.2
Sets conditions for an access list.
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Step 6
permit mr-home-address
Example:Router(config-std-nacl)# permit 5.5.5.3
Sets conditions for an access list.
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Step 7
exit
Example:Router(config-std-nacl)# exit
Exits to global configuration mode.
Step 8
router protocol
Example:Router(config)# router ospf
Configures a routing protocol.
Step 9
redistribute mobile subnets
Example:Router(config-router)# redistribute mobile subnets
Enables redistribution of a virtual network into routing protocols.
Step 10
distribute-list access-list out
Example:Router(config-router)# distribute-list 1 out
(Optional) Suppresses networks from being advertised in updates.
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Step 11
exit
Example:Router(config-router)# exit
Exits to global configuration mode.
Step 12
access-list access-list-number deny source
Example:Router(config)# access-list 1 deny 5.5.5.0
Defines a standard IP access list.
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Step 13
access-list access-list-number permit any
Example:Router(config)# access-list 1 permit any
Defines a standard IP access list.
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Step 14
Repeat Steps 3 through 7 for each HA configured on the mobile router. Repeat Steps 8 through 13 for each HA if virtual networks are configured.
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Troubleshooting Tips
Care-of Address List Operation
Any time an HA has a care-of address access list configured, the access list should permit the mobile router home address (for deregistration) and the interesting list of care-of addresses (for registration).
The care-of address lists are designed to allow registrations only of a select group of care-of addresses on an HA. For priority HA assignment to work, deregistrations need to be allowed as well. The deregistration is sent with the mobile router home address in the care-of address field of the deregistration. If the home address is not permitted, any deregistration will be dropped by the access list. Priority HA assignment does not work properly if the deregistrations are dropped.
Virtual Network Advertisements
In a network using mobile routers configured with priority HA assignment and multiple HAs, the HAs may be sharing routing information. If so, each HA will advertise a route to the same mobile virtual network through the redistribute mobile command. This situaton results in multiple routes to the same virtual network, which can cause routing conflicts and lost packets. The distribute-list command configured on each HA will prevent the advertisement of the virtual-network for the mobile routers. There is no dependency on registration for this to occur.
Configuring HA Priorities on the Mobile Router
This task describes how to configure HA priorities on the mobile router.
SUMMARY STEPS
1.
2.
3.
4.
5.
6.
DETAILED STEPS
Step 1
enable
Example:Router> enable
Enables privileged EXEC mode.
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Step 2
configure terminal
Example:Router# configure terminal
Enters global configuration mode.
Step 3
ip mobile router
Example:Router(config)# ip mobile router
Enables the mobile router and enters mobile router configuration mode.
Step 4
home-agent ip-address priority level
Example:Router(mobile-router)# home-agent 1.1.1.1 priority 101
Specifies the home agent that the mobile router uses during registration.
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Step 5
end
Example:Router(mobile-router)# end
Exits to privileged EXEC mode.
Step 6
show ip mobile router
Example:Router# show ip mobile router
Displays configuration information and monitoring statistics about the mobile router.
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Examples
This section provides the following output example for the show ip mobile router command:
The following example shows that the mobile router is currently registered with the best home agent located at 200.200.200.1:
Router# show ip mobile routerMobile RouterEnabled 01/01/02 10:01:34Last redundancy state transition NEVERConfiguration:Home Address 5.5.5.3 Mask 255.255.255.0Home Agent 200.200.200.1 Priority 102 (best) (current)100.100.100.1 Priority 101Registration lifetime 90 secRetransmit Init 1000, Max 5000 msec, Limit 3Extend Expire 120, Retry 3, Interval 10Monitor:Status -Registered-Active foreign agent 3.3.3.2, Care-of 3.3.3.2On interface Ethernet5/3Configuration Examples for Cisco Mobile Networks—Priority HA Assignment
This section provides the following configuration example:
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HA Priority Configuration Example
In the following example, two home agents are configured with access lists that allow the mobile router to choose the best HA to register with:
Home Agent1
interface Loopback0ip address 100.100.100.1 255.255.255.255!interface Ethernet1ip address 2.2.2.1 255.255.255.0!router mobile!router ospf 100redistribute mobile subnetsnetwork 2.0.0.0 0.255.255.255 area 0network 100.100.100.0 0.255.255.255 area 0! Suppresses virtual network to be advertised in updatesdistribute-list 1 out!ip mobile home-agent care-of-access HA1-FA1ip mobile virtual-network 5.5.5.0 255.255.255.0ip mobile host 5.5.5.3 virtual-network 5.5.5.0 255.255.255.0 lifetime 90ip mobile mobile-networks 5.5.5.3description Jetnetwork 6.6.6.0 255.255.255.0ip mobile secure host 5.5.5.3 spi 100 key hex 12345678123456781234567812345678 algorithm md5 mode prefix-suffix!ip access-list standard HA1-FA1! MR CCOApermit 4.4.4.2! FA1 COApermit 7.7.7.1! MR home addresspermit 5.5.5.3!! Denies virtual network toaccess-list 1 deny 5.5.5.0 0.0.0.255access-list 1 permit anyHome Agent 2
interface Loopback0ip address 200.200.200.1 255.255.255.255!interface Ethernet0ip address 1.1.1.1 255.255.255.0!router mobile!router ospf 100redistribute mobile subnetsnetwork 1.0.0.0 0.255.255.255 area 0network 200.200.200.0 0.255.255.255 area 0! Suppresses virtual network to be advertised in updatedistribute-list 1 out!ip mobile home-agent care-of-access HA2-FA2ip mobile virtual-network 5.5.5.0 255.255.255.0ip mobile host 5.5.5.3 virtual-network 5.5.5.0 255.255.255.0 lifetime 90ip mobile mobile-networks 5.5.5.3description Jetnetwork 6.6.6.0 255.255.255.0ip mobile secure host 5.5.5.3 spi 200 key hex 12345678123456781234567812345678 algorithm md5 mode prefix-suffix!ip access-list standard HA2-FA2! FA COApermit 3.3.3.2! MR home addresspermit 5.5.5.3!access-list 1 deny 5.5.5.0 0.0.0.255access-list 1 permit anyMobile Router
interface Loopback0ip address 5.5.5.3 255.255.255.255!! CCOA roaming interface registers with HA1 onlyinterface Ethernet5/1ip address 4.4.4.3 255.255.255.0ip mobile router-service roam priority 99ip mobile router-service collocated gateway 4.4.4.2!! This roaming interface will use FA COA to registerinterface Ethernet5/3ip address 3.3.3.3 255.255.255.0ip mobile router-service roam!! Mobile Network interfaceinterface Ethernet5/4ip address 6.6.6.3 255.255.255.0!router mobile!ip mobile secure home-agent 100.100.100.1 spi 100 key hex 12345678123456781234567812345678 algorithm md5 mode prefix-suffixip mobile secure home-agent 200.200.200.1 spi 200 key hex 12345678123456781234567812345678 algorithm md5 mode prefix-suffix!ip mobile routeraddress 5.5.5.3 255.255.255.0home-agent 100.100.100.1 priority 101home-agent 200.200.200.1 priority 102register lifetime 90Additional References
For additional information related to the Cisco Mobile Networks—Priority HA Assignment feature, see to the following sections:
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Related Documents
Standards
No 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
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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Technical Assistance
Command Reference
None
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.
home agent—A router on a home network of the mobile node or that tunnels packets to the mobile node or mobile router while they are away from home. It keeps current location information for registered mobile nodes called a mobility binding.
foreign agent—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.
mobile network—A network that moves with the mobile router. A mobile network is a collection of hosts and routes that are fixed with respect to each other but are mobile, as a unit, with respect to the rest of the Internet.
mobile router—A mobile node that is a router. It provides for the mobility of one or more entire networks moving together, perhaps on an airplane, a ship, a train, an automobile, or bicycle. The nodes connected to a network served by the mobile router may themselves be fixed nodes or mobile nodes or routers.
Note
Guest
