Link local address assignment for interfaces of overlay distributed router
Some embodiments provide a novel method for assigning a unique internet protocol version 6 (IPv6) link-local address to each interface of a software router implementing a plurality of logical interfaces for a corresponding plurality of logical networks. In some embodiments, the method, for each logical interface, determines a logical network identifier for a logical network corresponding to the logical interface and generates the link-local address based on that logical network identifier (e.g., a virtual network identifier (VNI)).
1. A non-transitory machine readable medium storing a program for assigning a unique internet protocol version 6 (IPv6) link-local address to each interface of a software router implementing a plurality of logical interfaces for a corresponding plurality of logical networks, the program for execution by a set of processing units, the program comprising sets of instructions for:
for each logical interface,
determining an identifier of the corresponding logical network;
based on the identifier, generating an IPv6 link-local address for the logical interface including the identifier of the corresponding logical network; and
distributing the generated IPv6 link-local address to other local network elements in the corresponding logical network for the other local network elements to use to address the logical interface.
2. The non-transitory machine readable medium of claim 1 , wherein the identifier is a virtual network identifier (VNI).
3. The non-transitory machine readable medium of claim 2 , wherein the VNI is one of a virtual local area network (VLAN) identifier and a virtual extensible local area network identifier.
4. The non-transitory machine readable medium of claim 3 , wherein, a VLAN identifier is a 12-bit identifier and a VXLAN identifier is a 24-bit identifier.
5. The non-transitory machine readable medium of claim 1 , wherein each logical interface uses a same, shared MAC address.
6. The non-transitory machine readable medium of claim 5 , wherein the generated IPv6 link-local address for each logical interface comprises:
a first set of 10 bits indicating that the generated address is a link-local address;
a last set of bits based on the shared MAC address of the logical interface;
a set of bits between the first and last sets of bits based on the identifier of the corresponding logical network.
7. The non-transitory machine readable medium of claim 6 , wherein the last set of bits is a set of 64 bits comprising a 64-bit modified extended unique identifier (modified EUI-64) comprising the first 24 bits of the shared MAC address with the seventh bit toggled followed by the hexadecimal values FFFE followed by the last 24 bits of the MAC address.
8. The non-transitory machine readable medium of claim 6 , wherein the set of bits between the first and last sets of bits is a virtual network identifier (VNI) of the corresponding logical network immediately following the first set of 10 bits.
9. The non-transitory machine readable medium of claim 6 , wherein the set of bits between the first and last sets of bits is a virtual network identifier (VNI) of the corresponding logical network immediately preceding the last set of bits based on the shared MAC address of the logical interface.
10. The non-transitory machine readable medium of claim 6 , wherein the set of bits between the first and last sets of bits is a virtual network identifier (VNI) of the corresponding logical network located at a same arbitrary location between the first and last sets of bits for each generated link-local address.
11. The non-transitory machine readable medium of claim 6 , wherein the set of bits between the first and last set of bits is a virtual network identifier (VNI) of the corresponding logical network located at an arbitrary location between the first and last sets of bits for each generated link-local address, wherein at least first and second generated link-local addresses for first and second logical interfaces use a different location for the VNI.
12. The non-transitory machine readable medium of claim 1 further comprising sets of instructions for:
receiving, at the software router, a data message directed to a logical interface of the software router;
comparing the IPv6 link-local address to the generated IPv6 link-local addresses for the different logical interfaces to determine the logical interface to which the data message is addressed.
13. The non-transitory machine readable medium of claim 12 , wherein the received data message is one of internet control message protocol (ICMP) data message, a neighbor discovery protocol (NDP) data message, and a dynamic host configuration protocol version 6 (DHCPv6) data message.
14. A method for assigning a unique internet protocol version 6 (IPv6) link-local address to each interface of a software router implementing a plurality of logical interfaces for a corresponding plurality of logical networks, the method comprising:
for each logical interface,
determining an identifier of the corresponding logical network;
based on the identifier, generating an IPv6 link-local address for the logical interface including the identifier of the corresponding logical network; and
distributing the generated IPv6 link-local address to other local network elements in the corresponding logical network for the other local network elements to use to address the logical interface.
15. The method of claim 14 , wherein the identifier is one of a virtual local area network (VLAN) identifier and a virtual extensible local area network (VXLAN) identifier.
16. The method of claim 14 , wherein each logical interface uses a same, shared MAC address and the generated IPv6 link-local address for each logical interface comprises:
a first set of 10 bits indicating that the generated address is a link-local address;
a last set of bits based on the shared MAC address of the logical interface;
a set of bits between the first and last sets of bits based on the identifier of the corresponding logical network.
17. The method of claim 16 , wherein the last set of bits is a set of 64 bits comprising a 64-bit modified extended unique identifier (modified EUI-64) comprising the first 24 bits of the shared MAC address with the seventh bit toggled followed by the hexadecimal values FFFE followed by the last 24 bits of the MAC address.
18. The method of claim 16 , wherein the set of bits between the first and last sets of bits is a virtual network identifier (VNI) of the corresponding logical network located at a same arbitrary location between the first and last sets of bits for each generated link-local address.
19. The method of claim 14 further comprising:
receiving, at the software router, a data message directed to a logical interface of the software router;
comparing the IPv6 link-local address to the generated IPv6 link-local addresses for the different logical interfaces to determine the logical interface to which the data message is addressed.
20. The method of claim 19 , wherein the received data message is one of internet control message protocol (ICMP) data message, a neighbor discovery protocol (NDP) data message, and a dynamic host configuration protocol version 6 (DHCPv6) data message.