About Mobile IPv6 Testing
The Mobile IP IPv6 test cases, the IPv6 HA Nodal and IPv6 CN Nodal test cases, give you the ability to test either an HA or a CN in an IPv6 network.
In the default configurations shown below, the MNs can simulate attaching to a foreign link. When it is attached to a foreign link, the MN registers with its HA and reverse-tunneling is used for bearer plane traffic exchanged with a CN. A Returning Home test simulates MNs moving from a foreign link to the home link.
You can add data traffic to the test, with the CN acting as a Network Host, and define the MN behavior with the following options:
In the IPv6 HA Nodal test case, the test system simulates the MNs and a CN. When the MN is attached to a foreign link, as shown below, the HA SUT handles the MN-HA registrations and bearer plane traffic exchanged between the MNs and the CN is reverse-tunneled through the HA.
In the IPv6 CN Nodal test case, the test system simulates the MNs and simulates the routing functionality of an HA. When the MN is attached to a foreign link, as shown below, the HA node relays the data traffic between the MNs and the CN SUT. Route Optimization is normally included when testing a CN, which requires that Data Traffic be included in the test.
NOTE: In the IPv6 CN Nodal test case, MN-HA Registration, Prefix Solicitation, and Home Agent Discovery serve no purpose since both the MN and HA are simulated, and therefore these messages are not sent even though they may be enabled. |
MN-HA Registration
When an MN attaches to
a foreign link, it must register its care-of address with an HA using
MIPv6. The MN may already have registered a care-of address with the HA,
in which case it updates the existing binding with the new care-of address.
When the MN returns to its home link, it can request that the HA delete
the binding (see Mobility). The Binding Update
message accomplishes both registration and deletion tasks and is normally
protected with IPSec in transport mode.
To register a care-of address and establish a binding, the MN sends a Binding Update to the HA that includes the care-of address, the MN's home address, and the requested lifetime for the binding. The HA responds with a Binding Acknowledgement to the care-of address that indicates success or failure with the Status field.
To delete a binding, the MN sends a Binding Update with a care-of address equal to its home address, and a lifetime of 0. The HA responds with a Binding Acknowledgement sent to the MN's home address.
The requested lifetime for a registration is defined by the Lifetime parameter. If the HA responds with a shorter lifetime, that value will be used in the MN's binding list. The MN can update the binding before the lifetime expires when you use the Re-registration checkbox. When prefix solicitation is enabled, the MN will update its home address before re-registering.
Prefix Solicitation
An MN's home address has
a lifetime associated with it when it is away from its home link. Before
this lifetime expires, the MN should send an ICMPv6 Mobile Prefix Solicitation
to its HA to check for any changes in the network prefix numbering. It
should also perform prefix solicitation whenever it receives a Binding
Acknowledgement from the HA with a Status value of 1, indicating that
the network has changed. Prefix solicitation messages are normally protected
with IPSec in transport mode.
The HA responds with a Mobile Prefix Advertisement containing prefix information that the MN uses to form its home address.
Use the Prefix Solicitation checkbox to include prefix solicitation in the test.
Home Agent Discovery
When an MN does not know
the address of a router on its home link that can serve as its HA, it
can dynamically discover the addresses of all HAs in the home link. The
MN sends an ICMPv6 Home Agent Address Discovery Request to the HA anycast
address for its home link. An HA will respond with a Home Agent Address
Discovery Reply that includes the addresses for all HAs on the home link.
The MN can then proceed to send a Binding Update to each HA until it receives a Binding Acknowledgement indicating that an HA has accepted the MN's registration.
Although the HA SUT's IP address is always known within the test system, you can simulate dynamic discovery with the Home Agent Discovery checkbox. The HA anycast address is defined in the SUT Administration window by including a prefix length with the HA's IP Address.
Route Optimization
When the MN is attached to a foreign link, as shown below, Route Optimization allows the MN and the CN to exchange data packets without the need of an HA. A return routability test is performed, and if it succeeds, the MN registers its care-of address with the CN. If the test fails, packets destined for the MN are routed through the HA, and the MN reverse-tunnels packets destined for the CN to the HA.
Route Optimization is optional in the IPv6 HA Nodal and IPv6 CN Nodal test cases when Data Traffic is included in the test. It is controlled by the Route Optimization checkbox on the Data Traffic pane.
Return Routability
This ICMPv6 message exchange
between the MN and the CN accomplishes three purposes:
Verify that the CN can support Route Optimization.
Verify that messages sent from the CN to both the home and care-of addresses of the MN are deliverable.
Establish the security tokens that allow the CN to accept Binding Update messages from the MN.
The CN includes certain data, keygen tokens, in its response messages that the MN must return in the form of a binding management key (Kbm) in subsequent Binding Update messages. The Kbm serves to verify the MN's identity to the CN. The CN discards any Binding Update from the MN that does not include a valid Kbm.
The MN sends a Home Test Init message and a Care of Test Init message to the CN using ICMPv6. The Home Test Init is reverse-tunneled through the HA, using IPSec in tunnel mode. The MN's home address is the source address. The care of Test Init message is sent directly to the CN, and uses the MN's care-of address as the source address.
The CN responds to the Home Test Init with a Home Test message sent to the MN's home address and routed through the HA, which uses an IPSec tunnel to relay the message to the MN. The MN uses the tokens received in the Home Test message to form the Kbm used with the binding to its home address. The CN sends a Care of Test message directly to the MN at its care-of address. The MN uses the tokens received in the Care of Test message to form the Kbm used with the binding to its care-of address.
MN-CN Registration
After both test messages are received, the MN uses MIPv6 to send a Binding Update to the CN and register its care-of address. The MN always requests a Binding Acknowledgement from the CN.
The same Lifetime is requested for both HA and CN bindings. If the CN returns a shorter lifetime, that value will be used. The MN can update the binding before the lifetime expires when you use the Re-registration checkbox.
Binding Refresh
When Route Optimization is used, the CN may request that the MN update its care-of address binding by sending a Binding Refresh Request before the end of the binding lifetime. If the MN's care-of address is still valid, it responds with a Binding Update and re-registers with the CN. If the MN is not reachable at its care-of address, the binding is allowed to expire.
In the IPv6 HA Nodal test case, you can define the maximum binding lifetime allowed by the emulated CN with the Lifetime parameter in the Data Traffic pane. You can use the Re-registration checkbox to specify that the emulated CN send Binding Refresh Requests.
Test Configurations
When Route Optimization is used in an IPv6 HA Nodal test, the HA SUT handles MN-HA registrations and the Home Test Init and Home Test messages exchanged between the simulated MNs and CN.
When Route Optimization is used in an IPv6 CN Nodal test, the CN SUT is tested for MIPv6 compatibility as well as handling any data traffic. The emulated HA handles the Home Test Init and Home Test messages exchanged between the simulated MNs and the SUT.
IPSec
When the MN is attached to a foreign link, the control messaging between an MN and an HA and bearer plane traffic reverse-tunneled through the HA is normally protected with IPSec. With the IPv6 HA Nodal test case, you can establish up to four SAs with the HA and define the type of traffic that is protected by each.
The MIPv6 IPSec tab contains the parameters used to define IKE authentication and encryption methods and provision each of the SAs (tunnels). A combination of Protocol Type, Payload ID Destination, and ESP Data Mode determines which messages are protected by each SA:
MN-HA Binding messages
Prefix Solicitation messages
Home Test Init and Home Test messages when Route Optimization is used
Data Traffic when Route Optimization is not used
IPSec is optional for all types of traffic — you can test without IPSec or with any of the four tunnel options. IKE Phase I is only performed once. The IPSec SAs are all negotiated using the same ISAKMP SA established during IKE Phase I.
When you use Route Optimization with Data Traffic, you can also establish an SA with the CN. The Data IPSec tab contains the parameters that provision this SA.
Mobility
When an MN detects that it has moved from one foreign link to another, the MN obtains a new care-of address and sends Binding Updates to register the address with its HA and any CNs in its binding list. The Mobile Node Mobility handoff test simulates MN mobility between foreign links.
When an MN detects that is has moved from a foreign link to its home link, the MNs can either send Binding Updates to delete their prior care of address bindings, or allow the bindings to expire when their lifetimes expire. An MN sends a Binding Update with the care-of address equal to its home address and a lifetime of 0 to delete a binding. The Returning Home handoff test simulates MN mobility between a foreign link and the home link, and bindings are deleted when the Delete checkbox is checked.