Multicast-enabled address resolution protocol (ME-ARP)

• US 6,640,251 B1
• Filed: 09/17/1999
• Issued: 10/28/2003
• Est. Priority Date: 03/12/1999
• Status: Expired due to Term

• Current Assignee: RPX Clearinghouse LLC (RPX Corporation)
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Mattson, Geoffrey, Bryden, Simon David, Pluim, Robert, Wiget, Marcel
• Primary Examiner(s): Najjar, Saleh
• Application Number:
  US09/398,370
• Time in Patent Office: 1,502 Days
• Field of Search: 709/228, 709/238, 709/242, 709/245
• US Class Current: 709/238
• CPC Class Codes: H04L 12/185 with management of multicast group membership
• CPC Class Codes: H04L 12/1886 with traffic restrictions for efficiency improvement, e.g. involving subnets or subdomains
• CPC Class Codes: H04L 12/4641 Virtual LANs, VLANs, e.g. virtual private networks [VPN] LAN interconnection over a bridge based backbone H04L12/462; encapsulation techniques H04L12/4633; routing of packets H04L45/00; packet switches H04L49/00; virtual private networks for security H04L63/0272
• CPC Class Codes: H04L 12/4645 Details on frame tagging routing of packets H04L45/00; support for virtual LAN H04L49/354
• CPC Class Codes: H04L 61/00 Network arrangements, protocols or services for addressing or naming
• CPC Class Codes: H04L 61/10 of different types
• CPC Class Codes: H04L 61/35 involving non-standard use of addresses for implementing network functionalities, e.g. coding subscription information within the address or functional addressing, i.e. assigning an address to a function

Abstract

A Multicast-Enabled Address Resolution Protocol (ME-ARP) is disclosed. This ME-ARP allows the building of independent IP based Virtual Private LAN segments (VPLS) over a multicast enabled IP backbone using stateless tunnels and optimal VPLS traffic forwarding. Each VPLS has an associated IP subnet which is completely independent from other VPLS or the underlying IP backbone itself. Each Customer Premises Equipment (CPE) device needs only to be configured with a VPLS identifier and its serving IP subnet per VPLS designated interface.

Claims

1. A method of sending a unicast IP packet from a first end station to a second end station, said first end and said second end stations being on the same logical subnet and connected to different CPEs, the method comprising:

receiving said unicast IP packet at a CPE associated with a second end station;

and said CPE associated with said second end station providing said second end station with address resolution information containing a mapping information between IP and lower layer physical addresses of said first and second end stations, said lower layer physical addresses being constructed by said CPE and containing VPN membership and physical remote location information such that the constructed lower layer addresses contain enough information for said CPE to forward the packet to the correct remote physical location, wherein

said address resolution information comprises remote tunnel endpoint address information which is directly mapped into a link layer address.

2. A method as claimed in claim 1, wherein unnumbered IP LAN interfaces generate the link layer address based on a configured VPN identifier and dynamically learned tunnel endpoints.

3. A method as claimed in claim 1, wherein said remote tunnel endpoint address information comprises a calculated address containing the tunnel source IP address, an interface unique VPN ID and a CPE ID.

4. A method of sending a multicast IP packet from a first end station to multiple end stations, said first and multiple end stations being on the same logical subnet and connected to different CPEs, comprising:

receiving said multicast IP packet at each CPE;

encapsulating said IP multicast packet; and

forwarding said encapsulated IP multicast packet to a VPN assigned multicast address wherein said IP multicast packet is received by each CPE which has been configured to said VPN, wherein at each CPE receiving said forwarded ARP request, the request is decapsulated to replace the source hardware address by a calculated address containing the tunnel source IP address, an interface unique VPN ID and a CPE ID.

5. A method as defined in claim 4, wherein said multicast IP packet comprises an IP broadcast packet.

6. A method as defined in claim 4, wherein each of said CPE is configured to said VPN using an IP multicast protocol.

7. A method as defined in claim 6, wherein said IP multicast protocol comprises one of an IGMP, DVMRP, MOSPF, MBGP and PIM multicast protocols.

8. A method of sending an IP packet from a first station to a second end station, wherein said first and second end stations are one the same logical subnet but connected to different CPEs, the method comprising:

a) sending from a first end station an ARP request with an Ethernet broadcast address;

b) at a first CPE associated;

with said first end station, intercepting said ARP request packet and verifying the intercepted IP address against a corresponding unnumbered virtual packet network (UV) IP interface;

c) if a match is verified, encapsulating said ARP request into an IPsec packet with a VPN identifier;

d) forwarding said IP sec packet to a VPN'"'"'s multicast address using configured local IP tunnel-endpoint as a-source address,

e) said first CPE further adding a local ARP entry for said first end station in its ARP table for said UVIP interface;

f) receiving said encapsulated ARP request at each CPE connected to said VPN;

g) unpacking, modifying and forwarding said ARP request out of the local UVIP interface when received at said CPE; and

h) modifying said ARP request at each CPE by replacing the original HW source address with a calculated MAC address containing the tunnel endpoint IP address from said first CPE and an interface unique VPN ID thuse providing a new HW source address to replace in the Ethernet header as well as in the ARP itself.