1. A method for providing topology awareness information within an IP network, said IP network comprises a central node (502) of a topology awareness system (500) that is adapted to store and process topology information, said central node (502) is connected to at least one topology awareness unit (P) that is implemented in a router (504) within said IP network, said unit comprises the functionality of a topology awareness system interface (402), wherein the method comprises the steps of:', '- transmitting a registration message from one of the topology awareness units (P) to the central node (502),', '- adding an identity of said unit (P) to a list of known units (P) at the central node (502), and', '-transmitting a response message from the central node (502) to the unit (P), wherein said response message has at least the capability to order the unit (P) to: keep the current relation with the central node (502), if the current relation between the unit (P) and the central node (502) is accepted; aggregate, if the central node (502) determines that the unit (P) is to be used as an aggregation point; or redirect to a previous aggregation point, if there exist a suitable aggregation point.

2. Method according to claim 1, wherein the method comprises the further step of: -deliÏx85eήng the topology information from the unit (P) to said central node (502) if the unit (P) is ordered to keep its current relationship with the central node (502).

3. Method according to claim 1, wherein the method comprises the further step of: -receiving topology information from other units (P) and,', '-delivering said topology information together with the topology information of said router to the central node (502), if the unit (P) is ordered to aggregate.

4. Method according to claim 1, wherein the method comprises the further steps of: -tearing down current relation from the unit (P) to the central node (502) and, -establishing a new relation between the unit and an aggregation point identified in said response message if the unit (P) is ordered to redirect.

5. Method according to any of previous claims 1-4, wherein the steps are repeated continuously.

6. Method according to any of previous claims 1-5, wherein all aggregation relations comprise a parent node and at least one child node.

7. Method according to claim 6, wherein the method comprises the further steps of: -issuing unsolicited aggregate messages from the unit (P) to any set of units it previously has had a parental relation to if a relation between said parent aggregation unit (P) and at least one child aggregation unit (P) is lost, and -issuing a further message from said unit (P) comprising information on new aggregation relations.

8. Method according to claim 1, wherein the method comprises the further step of: -transmitting unsolicited messages from the unit (P) when topology changes within the network is detected, and', '-filtering said unsolicited messages by the unit (P) in order to only transmit messages as a result of an actual change in the network topology, and avoid sending messages as a result of repeatedly updates.

9. Method according to claim 6, wherein the method comprises the further step of: -transmitting a compressed representation of topology information of a first unit (P) to a second unit (P) (or the central node (502)) in order to compare said compressed representation with a corresponding compressed representation for the second unit (or for the central node (502))

10. Method according to claim 9, wherein the method comprises the further step of: -performing synchronisation between the first unit (P) and the second unit (or the central node (502)) if a difference between said compressed representation of the first unit (P) and said compressed representation of the second unit (or the central node (502) is detected)

11. Method according to any of previous claims 1- 10, wherein the topology awareness unit (P) comprises the functionality of a network interface (404), wherein the method comprises the further step of: -collecting topology information from non-compliant routers (506)

12. Method according to previous claim 11, wherein said collecting step is performed by using SNMP (Simple Network Management Protocol)

13. Method according to any of previous claims 1- 12, wherein the topology awareness unit (P) comprises the functionality of a probe adjacencies interface', '(408), wherein the method comprises the further step of:', '-keeping tree- structured views of the network, wherein each unit (P) is keeping itself as the root of the tree and each branch of the trees consists of non- compliant routers (506) as intermediate nodes and adjacent units as leafs

14. Method according to the previous claim 13, wherein each adjacent pair of units (P) has one single relationship

15. Method according to any of previous claims 1- 14, wherein the method comprises the further step of:', '-keeping each adjacency alive by transmitting messages from each unit (P) to substantially all of its adjacent units (P)

16. Method according to any of claims 13- 15, wherein the method comprises the further steps of:', '-defining a territory of non-compliant routers (506) that a unit (P) is responsible for probing, wherein each non-compliant router (506) belongs to a territory, and -keeping a list of all non-compliant routers (506) belonging to the territory of said unit (P), wherein each router is associated with a metric that indicates the distance to the non-compliant router from said unit (P) and an identifier of said unit (P)

17. Method according to previous claim 16, wherein there is one master node and one slave node for each pair of adjacent units (P), wherein the master and slave relation is determined at the adjacency establishment, the method comprises the further steps of: -sending a subset of the list of non-compliant routers (506) to the master unit from the slave unit, and', '-comparing each router metric within the slave list with a corresponding router metric within the master list that occurs both in the slave list and the master list, wherein the unit (P) that has the smallest metric associated with the router', '(506) obtains said router (506) in its territory

18. Method according to any of claims 13-15, wherein the method comprises the further steps of: -obtaining local routing data by the unit (P) via local interfaces, and', '-using a network interface (404) by the unit to obtain path information to adjacent units, wherein the unit (P) transmits its local routing table and a representation of the paths to its adjacent units (P) across the topology awareness system interface (402)

19. Method according the any of previous claims 1-19, wherein the topology awareness unit (P) comprises the functionality of a local resources interface (406), wherein the method comprises the further step of:', '-obtaining topology information by using locally available resources at the router wherein the unit (P) is implemented.

20. Method according to previous claim 19, wherein said resources are kernel APIs.

21. Method according to claim 19, wherein said resources are approached by using Simple Network Management Protocol (SNMP).

22. A computer program product directly loadable into an internal memory of a router within an IP network comprises the software code portions for performing the steps of claims 1-21.

23. A computer program product stored on a computer usable medium, comprises readable program for causing a router within an IP network to control the execution of the steps of claims 1-21.

24. A topology awareness unit (P) for providing topology awareness information within an IP network, the topology awareness unit (P) is implemented within a router (504) in the IP network and said unit belongs to a topology awareness system (500) that comprises additional topology awareness units (P) and a central node (502), wherein said unit (P) comprises the functionality of a topology awareness system interface (402), i.e.: -means for transmitting a registration message to the central node (502), and', '-means for receiving a response message from the central node (502), wherein said response message has at least the capability to order the unit (P) to: keep the current relation with the central node (502), if the current relation between the unit (P) and the central node (502) is accepted; aggregate, if the central node (502) determines that the unit (P) is to be used as an aggregation point; or redirect to a previous aggregation point, if there exist a suitable aggregation point.

25. Topology awareness unit (P) according to claim 24, wherein said unit (P) comprises the functionality of a network interface (404), i.e. means for collecting topology information from non-compliant routers (506).

26. Topology awareness unit (P) according to any of previous claims 24-25, wherein said unit (P) comprises the functionality of a probe adjacencies interface (408), i.e.:', '-means for keeping tree-structured views of the network, wherein each unit (P) is keeping itself as the root of the tree and each branch of the trees comprises non- compliant routers (506) as intermediate nodes and adjacent units as leafs.

27. Topology awareness unit (P) according the any of previous claims 24-26, wherein said unit comprises the functionality of a local resources interface (406), i.e.: -means for obtaining topology information by using locally available resources at the router (504) wherein the unit (P) is implemented.']