Internal packet steering within a wireless access gateway

Patent metadata

Field	Value
Publication number	US-9485196-B1
Application number	US-201313957201-A
Country	US
Kind code	B1
Filing date	Aug 1, 2013
Priority date	Aug 1, 2013
Publication date	Nov 1, 2016
Grant date	Nov 1, 2016

Abstract

In general, techniques are described for steering data traffic for a subscriber session from a network interface of a wireless access gateway to an anchoring one of a plurality of forwarding units of the wireless access gateway using a layer 2 (L2) address of the data traffic. For example, a wireless access gateway for a wireless local area network (WLAN) access network is described as having a decentralized data plane that includes multiple forwarding units for implementing subscriber sessions. Each forwarding unit may present a network interface for sending and receiving network packets and includes packet processing capabilities to enable subscriber data packet processing to perform the functionality of the wireless access gateway. The techniques enable steering data traffic for a given subscriber session to a particular one of the forwarding units of the wireless access gateway using an L2 address of the data traffic.

First claim

What is claimed is:

1. A method performed by a wireless access gateway of a wireless local area network (WLAN) access network, the method comprising:
assigning each forwarding unit of a plurality of forwarding units a different gateway layer 2 (L2) address from a plurality of gateway L2 addresses that each identifies the wireless access gateway as a gateway device that terminates the WLAN access network at layer 2 and provides access to a layer 3 (L3) network for packets destined to any of the gateway L2 addresses, wherein the plurality of forwarding units are internal to the wireless access gateway, and wherein the wireless access gateway includes an upstream interface for a mobility tunneling protocol operating over the L3 network, wherein the upstream interface is to a mobile gateway of a mobile service provider network;
selecting, by the wireless access gateway, an anchor forwarding unit of the plurality of forwarding units to anchor a subscriber session for a wireless endpoint device;
sending, by the wireless access gateway to the wireless endpoint device, the gateway L2 address assigned to the anchoring forwarding unit to be used by the wireless endpoint device as a gateway L2 address for the wireless access gateway;
receiving, by an ingress forwarding unit of the plurality of forwarding units and from the wireless endpoint device, a packet comprising a destination L2 address;
in response to determining, by the ingress forwarding unit, the destination L2 address of the packet matches the gateway L2 address assigned to the anchor forwarding unit:
forwarding, by the ingress forwarding unit, the packet to the anchor forwarding unit; and
processing, by the anchor forwarding unit using a subscriber session context for the subscriber session for the wireless endpoint device, the packet to remove the L2 destination address and generate an encapsulated packet having a mobility tunneling protocol header for output via the upstream interface.

2. The method of claim 1 , further comprising:
receiving, by the ingress forwarding unit from the wireless endpoint device, an address resolution protocol request to resolve a default gateway layer 3 (L3) address for the wireless access gateway;
determining, by the wireless access gateway and based on a source L3 address of the address resolution protocol request, the subscriber session for the wireless endpoint device is anchored by the anchor forwarding unit; and
generating and sending, by the wireless access gateway to the wireless endpoint device in response to determining the subscriber session for the wireless endpoint device is anchored by the anchor forwarding unit, an address resolution protocol response that includes the gateway L2 address assigned to the anchor forwarding unit to be used, by the wireless endpoint device, as a gateway L2 address for the wireless access gateway.

3. The method of claim 1 , further comprising:
receiving, by the wireless access gateway, a dynamic host configuration protocol request from the wireless endpoint device;
sending, by the wireless access gateway and in response to the dynamic host configuration protocol request, a dynamic host configuration protocol response that includes a loopback layer 3 (L3) address of the wireless access gateway as a default gateway L3 address.

4. The method of claim 1 , wherein the wireless access gateway presents a uniform layer 3 (L3) interface comprising a default gateway L3 address for all subscriber sessions attached to the wireless access gateway.

5. The method of claim 1 , wherein the packet does not comprise mobility tunneling protocol encapsulation.

6. The method of claim 1 , further comprising:
storing, to each forwarding unit of the plurality of forwarding units, a lookup table having entries that map the different gateway L2 addresses to the forwarding units of the plurality of forwarding units as assigned;
mapping, by the ingress forwarding unit after determining that the destination L2 address of the packet matches the gateway L2 address assigned to the anchor forwarding unit and using the lookup table stored to the ingress forwarding unit, the destination L2 address of the packet to the anchor forwarding unit.

7. The method of claim 1 , wherein the wireless endpoint device comprises a first wireless endpoint device having a layer 3 (L3) address, the method further comprising:
tearing down the subscriber session;
sending, by the wireless access gateway, a message to a second wireless endpoint device assigning the L3 address to the second wireless endpoint device;
selecting, by the wireless access gateway, a new anchor forwarding unit of the plurality of forwarding units to anchor the new subscriber session and associating the L3 address with a new subscriber session, wherein the new anchor forwarding unit is not the anchor forwarding unit; and
sending an L2 address associated with the new anchor forwarding unit to the second wireless endpoint device to be used as a gateway L2 address for the wireless access gateway.

8. The method of claim 7 , receiving a subsequent packet by the ingress forwarding unit; determining, by the ingress forwarding unit, a destination L2 address of the subsequent packet, wherein the subsequent packet includes a source L3 address that is the L3 address;
determining, by the ingress forwarding unit, the new anchor forwarding unit that is associated with the destination L2 address of the subsequent packet;
forwarding the packet from the ingress forwarding unit to the new anchor forwarding unit; and
processing, by the new anchor forwarding unit, the subsequent packet using a subscriber session context for the new subscriber session.

9. A wireless access gateway for a wireless local area network (WLAN) access network, the wireless access gateway comprising:
a plurality of forwarding units internal to the wireless access gateway; and
a routing unit configured to assign each forwarding unit of the plurality of forwarding units a different gateway layer 2 (L2) address from a plurality of gateway L2 addresses that each identifies the wireless access gateway as a gateway device that terminates the WLAN access network at layer 2 and provides access to a layer 3 (L3) network for packets destined to any of the gateway L2 addresses,
a subscriber management service unit configured to select an anchor forwarding unit of the plurality of forwarding units to anchor a subscriber session for a wireless endpoint device, and
wherein the subscriber management service unit is configured to send, to the wireless endpoint device, the gateway L2 address assigned to the anchoring forwarding unit to be used by the wireless endpoint device as a gateway L2 address for the wireless access gateway;
an upstream interface for a mobility tunneling protocol operating over the L3 network, wherein the upstream interface is to a mobile gateway of a mobile service provider network,
wherein an ingress forwarding unit of the plurality of forwarding units is configured to receive, from the wireless endpoint device, a packet comprising a destination L2 address,
wherein in response to a determination by the ingress forwarding unit that the destination L2 address of the packet matches the gateway L2 address assigned to the anchor forwarding unit:
the ingress forwarding unit is configured to forward the packet to the anchor forwarding unit, and
the anchor forwarding unit is configured to process, using a subscriber session context for the subscriber session for the wireless endpoint device, the packet to remove the L2 destination address and generate an encapsulated packet having a mobility tunneling protocol header for output via the upstream interface.

10. The wireless access gateway o

Assignees

• Juniper Networks Inc

Inventors

• Sankaran Krishna
• Yang Huiyang
• Gupta Santosh
• Chigurupati Prasad
• Hong Bin W

Classifications

• H04L47/568

  Calendar queues or timing rings · CPC title

• H04L12/2896

  Distributed processing, e.g. on line cards · CPC title

• H04L49/15 Primary

  Interconnection of switching modules · CPC title

• H04L49/254

  Centralised controller, i.e. arbitration or scheduling · CPC title

• H04L45/745

  Address table lookup; Address filtering · CPC title