WO2015002526A1

WO2015002526A1 - A method for enabling virtual local area network over wireless networks

Info

Publication number: WO2015002526A1
Application number: PCT/MY2014/000130
Authority: WO
Inventors: Sivanand Sridhar; Haseeb Shariq
Original assignee: Mimos Berhad
Priority date: 2013-07-04
Filing date: 2014-05-28
Publication date: 2015-01-08
Also published as: MY172120A

Abstract

The present invention relates to a method to allow multiple virtual local area network (VLAN) traffics to traverse over a wireless multi-hop network. The method is characterised by the steps of performing initialization phase, wherein the initialization phase includes exchanging media access control (MAC) addresses and Basic Service Set Identifications (BSSIDs) information between an access point (AP) (200) and a relay client (300); performing AP (200) to relay client (300) operation phase, wherein the AP (200) to relay client (300) operation phase includes transmitting a modified MAC address from AP (200) to the relay client (300); and performing relay client (300) to AP (200) operation phase, wherein the relay client (300) to AP (200) operation phase includes transmitting a modified transmitter MAC address at the packet header from relay client (300) to AP (200).

Description

A METHOD FOR ENABLING VIRTUAL LOCAL AREA NETWORK OVER

WIRELESS NETWORKS

FIELD OF INVENTION

The present invention relates to a method to allow multiple virtual local area network traffics to traverse over a wireless multi-hop network.

BACKGROUND OF THE INVENTION

Virtual Local Area Network (VLAN) is a domain wherein a single layer-2 network may be partitioned to create multiple distinct broadcast domains which are mutually isolated so that packets can only pass between them via one or more routers. A VLAN has the same attributes as a physical local area network (LAN), but it allows for end stations to be grouped together more easily even if they are not on the same network switch.

Typically the method of transporting VLAN traffic from first hop access point (AP) to the second hop AP involves a tunnel between the two APs. The tunnel encapsulates the VLAN traffic and transports them between the two APs. However, tunnel has its own problems where a tunnel encapsulates and adds overheads to each packet that passes through a tunnel. By encapsulating and adding overheads, the packet sizes increase but the payload remains the same.

If the maximum transmission unit (MTU) is not configured to accommodate the increased packet size, packet fragmentation starts to happen and this results in one packet being split into two. Fragmentation further degrades the performance of the network by adding excessive overheads that reduce the useful throughput of the overall system which could have been used by applications to send data across the network. When packets travel across a tunnel and arrive at their intermediate destination, they have to traverse up the protocol stack for de-capsulation and then back down for transmission to the next intermediate or final destination. If the next destination is an intermediate destination, the packets again need to be encapsulated. This process of unnecessary protocol stack traversal increases latency and degrades performance. Therefore, there is a need to provide a method to eliminate the tunnel and to allow multiple VLAN traffics to traverse over wireless networks that addresses the above drawbacks. SUMMARY OF INVENTION

The present invention relates to a method for enabling virtual local area network (VLAN) over wireless networks. The method is characterised by the steps of performing initialization phase, wherein the initialization phase includes exchanging media access control (MAC) addresses and Basic Service Set Identifications (BSSIDs) information between an access point (AP) (200) and a relay client (300); performing AP (200) to relay client (300) operation phase, wherein the AP (200) to relay client (300) operation phase includes transmitting a modified MAC address from AP (200) to the relay client (300); and performing relay client (300) to AP (200) operation phase, wherein the relay client (300) to AP (200) operation phase includes transmitting a modified transmitter MAC address at the packet header from relay client (300) to AP (200).

Preferably, the initialization phase includes the steps of connecting a relay client (300) to the relay Service Set Identification (SSID) interface (222) of the AP (200); creating a virtual interface (223) for each VLAN traffic over the relay SSID interface (222) in the AP (200); creating a virtual client (331) for each VLAN traffic over the wireless backhaul module (330) in the relay client (300); establishing a user defined MAC address for each virtual client (300) for handling the VLAN traffic from the AP (200); and exchanging the MAC addresses, VLAN traffics, SSIDs and BSSIDs information between the AP (200) and relay client (300) through message exchange or through pre-configuration.

Preferably, the AP (200) to relay client (300) operation phase includes the steps of receiving a packet at a virtual interface (223) of the AP (200); adding the modified MAC address of the relay client (300) and the actual destination address to be used by the virtual interface (223); forwarding the packet to the relay SSID interface (222) from the virtual interface (223); transmitting the packet to the relay client (300) from the relay SSID interface (222); identifying the MAC address in the packet header by the relay client (300) to determine the VLAN traffic; acknowledging the receipt of the packet by the relay client (300) to the relay SSID interface (222) at the AP (200); sending the packet to a virtual client (331) of the wireless backhaul module (330) from the relay client (300) based on the modified MAC address of the relay client (300); and forwarding the packet from the virtual client (331) to an appropriate VLAN module (311) or SSID (321) of the relay client (300).

Preferably, the relay client (300) to AP (200) operation phase includes the steps of receiving a packet at a virtual client (331) of the relay client (300); setting the modified transmitter MAC address by the virtual client (331); adding the source address at the packet header by the virtual client (331); forwarding the packet for transmission by the virtual client (331); transmitting the packet with the modified address fields from the relay client (300) to the relay SSID interface (222) of the AP (200); identifying the modified transmitter MAC address in the packet header by the AP (200); acknowledging the receipt of the packet by the AP (200) to the MAC address of the relay client (300); sending the packet to a virtual interface (223) of the AP (200) from the relay SSID interface (222) based on the modified transmitter MAC address; and forwarding the packet from the virtual interface (223) to an appropriate VLAN module (211) or SSID (221) of the AP (200).

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

FIG. 1 (a) illustrates a system (100) for enabling virtual local area network (VLAN) according to an embodiment of the present invention.

FIG. 1 (b) illustrates the access point (AP) (200) of FIG. 1 (a).

FIG. 1 (c) illustrates an example of a relay client (300) of FIG. 1 (a).

FIG. 2 illustrates the packet headers of the media access control (MAC) frame.

FIG. 3 illustrates a flow chart of the steps for the initialization phase according to an embodiment of the present invention. FIG. 4 illustrates a flow chart of the steps for operation phase from access point to relay client according to an embodiment of the present invention.

FIG. 5 illustrates a flow chart of the steps for operation phase from relay client to access point according to an embodiment of the present invention.

DESCRIPTION OF THE PREFFERED EMBODIMENT

A preferred embodiment of the present invention will be described herein below with reference to the accompanying drawings. In the following description, well known functions or constructions are not described in detail since they would obscure the description with unnecessary detail.

Reference is made initially to FIG. 1 (a), which illustrates a system (100) for enabling virtual local area network over wireless networks according to an embodiment of the present invention. The system (100) comprises of at least one access point (AP) (200) and at least one relay client (300). The AP (200) and the relay clients (300) are connected through wireless connections. The system (100) eliminates the tunnel and replaces it with a mechanism of a packet header modification. The APs (200) could be configured with prior knowledge of the header modification or they could negotiate the header modification technique amongst each other to have a common understanding of the header fields that have been modified.

Referring to FIG. 1 (b) which illustrates the AP (200) of FIG. 1 (a), an AP (200) comprises of a wired backhaul module (210) and an access module (220). The wired backhaul mode (210) comprises of one or more VLAN modules (211) depending on the number of VLAN traffics available. These VLAN modules (211) are used to serve different VLAN traffics. The access module (220) comprises of one or more Service Set Identifiers (SSIDs) (221) depending on the number of VLAN traffics available; and a relay SSID interface (222). The SSIDs (221) are used to allow the access module (220) to serve different VLAN traffics while the relay SSID interface (222) is used to connect the AP (200) to the relay client (300). The relay SSID interface (222) comprises of one or more virtual interfaces (223) depending on the number of VLAN traffics served by the next hop relay clients (300). The virtual interfaces (223) at the relay SSID interface (222) are used to aggregate all VLAN traffics and transfer to the relay clients (300). Finally, the corresponding VLAN module (211), SSID (221) and virtual interface (223) at the relay SSID interface (222) of a VLAN traffic are bridged together to allow the flow of VLAN traffic between them.

Referring now to FIG. 1 (c), it illustrates an example of a relay client (300) of FIG. 1 (a). The relay client (300) comprises of a wired backhaul module (310), an access module (320) and a wireless backhaul module (330). Similar to the AP (200), the wired backhaul mode (310) at the relay client (300) comprises of one or more VLAN modules (311) depending on the number of VLAN traffics available. The VLAN modules (311) are used to serve different VLAN traffics. The access module (320) of the relay client (300) comprises of one or more SSIDs (321) depending on the number of VLAN traffics available; and a relay SSID interface (322). The SSIDs (321) are used to allow the access module (320) to serve different VLAN traffics while the relay SSID interface (322) is used to connect one relay client (300a) to the next hop relay clients (300b) as shown in FIG.1(a). The relay SSID interface (322) at the relay client (300) comprises of one or more virtual interfaces (323) depending on the number of VLAN traffics served by the next hop relay clients (300). The wireless backhaul module (330) comprises of one or more virtual clients (331) depending on the number of VLAN traffics available. These virtual clients (331) are used to relay the VLAN traffics to the previous hop which can either be an AP (200) or a relay client (300). Finally, the corresponding VLAN module (311), SSID (321), virtual interface (323) at the relay SSID interface (322) and virtual client (331) of a VLAN traffic are bridged together to allow the flow of VLAN traffic between them.

In order to transport VLAN traffic from the AP (200) to the relay client (300) and vice versa, the packet headers need to be modified. The packet headers of the media access control (MAC) frame (400) are shown in FIG. 2. The fields of interest in the MAC frame (400) are the "To Distributed System (DS)" (401), "From DS" (402), Address 1 (403), Address 2 (404), Address 3 (405) and Address 4 (406) fields. The "To DS" (401) and "From DS" (402) fields determine the direction of the traffic flow. Table 1

Table 2

Table 1 shows the role of the different address fields before modification of the MAC frame. When the packets flow are neither "From DS" (402) nor "To DS" (401), the Address 1 (403) field holds the Destination Address (DA), Address 2 (404) field holds the Source Address (SA), Address 3 (405) field holds the BSSID and Address 4 (406) field is not utilized. When packets flow "From DS" (402), then Address 1 (403) field holds the DA, Address 2 (404) field holds the BSSID, Address 3 (405) field holds the SA and Address 4 (406) field is not utilized. When packets flow "To DS" (401), then Address 1 (403) holds the BSSID, Address 2 (404) holds the SA, Address 3 (405) holds the DA and Address 4 (406) is not utilized. When both "From DS" (402) and "To DS" (401) fields are active, Address 1 (403) holds the Receiver Address (RA), Address 2 (404) holds Transmitter Address (TA), Address 3 (405) holds DA and Address 4 (406) holds SA.

Table 2 shows the role of the different address fields after modification of the MAC frame. It can be observed from Table 2 that for the case of the packets flow are neither "From DS" (402) nor "To DS"; and when both "From DS" (402) and "To DS" (401) fields are active, there are no changes. However, in the case of transmission "From DS" (402), DA has been moved to the previously unutilized Address 4 (406) field and the Address 1 (403) field now holds the modified RA, which is the relay client's (300) address corresponding to different VLAN traffics. In the case of transmission "To DS" (401), SA has been moved to the previously unutilized Address 4 (406) field and the Address 2 (404) field now holds the modified TA, which is the relay client's (300) address corresponding to different VLAN traffics.

Referring now to FIG. 3, it shows a flow chart of the steps for the initialization phase according to an embodiment of the present invention. During operation, a relay client (300) is connected to the relay SSID interface (222) of an AP (200) as in step 500. This is to establish a connection between the AP (200) and the relay client (300). The AP (200) then creates a virtual interface (223) for each VLAN traffic over the relay SSID interface (222) in the AP (200) as in step 501. The relay client (300) creates a virtual client (331) for each VLAN traffic over the wireless backhaul module (330) in the relay client (300) as in step 502. Next, the relay client (300) establishes a user defined MAC address for each virtual client (331) as in step 503 for handling the VLAN traffic from the AP (200). Finally, the MAC addresses, VLAN traffics, SSIDs and Basic Service Set Identifications (BSSIDs) information are exchanged and mapped between the AP (200) and relay client (300) through message exchange or through pre-configuration as in step 504. This step is to achieve a common understanding between the AP (200) and the relay client (300) about the address mapping to different VLAN traffics.

Referring now to FIG. 4, it shows a flow chart of the steps for operation phase from AP (200) to relay client (300) according to an embodiment of the present invention. When the AP (200) receives a packet at a virtual interface (223) as in step 600, the virtual interface (223) adds the modified MAC address of the relay client (300) and the actual destination address to be used before it forwards the packet to the relay SSID interface (222) as in step 601. Next, the relay SSID interface (222) transmits the packet to the relay client (300) as in step 602. Upon receiving the packet, the relay client (300) identifies the MAC address in the packet header to determine the VLAN traffic. The relay client (300) then acknowledges the receipt of the packet to the relay SSID interface (222) at the AP (200) as in step 603. The relay client (300) sends the packet to the virtual client (331) of the wireless backhaul module (330) based on the modified MAC address of the relay client (300) as in step 604. Finally, the virtual client (331) forwards the packet to the appropriate VLAN module (311) or SSID (321) as in step 605.

Moving on to FIG. 5, it shows a flow chart of the steps for operation phase from relay client (300) to AP (200) according to an embodiment of the present invention. Initially, the relay client (300) receives a packet at the virtual client (331) of the wireless backhaul module (330) as in step 700. The virtual client (331) then sets the modified transmitter MAC address and adds the source address at the packet header before it forwards the packet for transmission as in step 701. The relay client (300) transmits the packet with the modified address fields to the relay SSID interface (222) of the AP (200) as in step 702. Upon receiving the packet, the relay SSID interface (222) of the AP (200) identifies the modified transmitter MAC address and acknowledges the receipt of the packet to the MAC address of the relay client (300) as in step 703. Next, the relay SSID interface (222) passes the packet to the virtual interface (223) based on the modified transmitter MAC address as in step 704. Finally, the virtual interface (223) forwards the packet to the appropriate VLAN module (211) or SSID (221) as in step 705.

While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specifications are words of description rather than limitation and various changes may be made without departing from the scope of the invention.

Claims

A method for enabling virtual local area network (VLAN) over wireless networks is characterised by the steps of:

a) performing initialization phase, wherein the initialization phase includes exchanging media access control (MAC) addresses and Basic Service Set Identifications (BSSIDs) information between an access point (AP) (200) and a relay client (300);

b) performing AP (200) to relay client (300) operation phase, wherein the AP (200) to relay client (300) operation phase includes transmitting a modified MAC address from AP (200) to the relay client (300); and c) performing relay client (300) to AP (200) operation phase, wherein the relay client (300) to AP (200) operation phase includes transmitting a modified transmitter MAC address at the packet header from relay client (300) to AP (200).

The method as claimed in claim 1 , wherein the initialization phase includes the steps of:

a) connecting a relay client (300) to the relay Service Set Identification (SSID) interface (222) of the AP (200);

b) creating a virtual interface (223) for each VLAN traffic over the relay SSID interface (222) in the AP (200);

c) creating a virtual client (331) for each VLAN traffic over the wireless backhaul module (330) in the relay client (300);

d) establishing a user defined MAC address for each virtual client (300) for handling the VLAN traffic from the AP (200); and

e) exchanging the MAC addresses, VLAN traffics, SSIDs and BSSIDs information between the AP (200) and relay client (300) through message exchange or through pre-configuration.

The method as claimed in claim 1 , wherein the AP (200) to relay client (300) operation phase includes the steps of:

a) receiving a packet at a virtual interface (223) of the AP (200);

b) adding the modified MAC address of the relay client (300) and the actual destination address to be used by the virtual interface (223); c) forwarding the packet to the relay SSID interface (222) from the virtual interface (223);

d) transmitting the packet to the relay client (300) from the relay SSID interface (222);

e) identifying the MAC address in the packet header by the relay client (300) to determine the VLAN traffic;

f) acknowledging the receipt of the packet by the relay client (300) to the relay SSID interface (222) at the AP (200);

g) sending the packet to a virtual client (331) of the wireless backhaul module (330) from the relay client (300) based on the modified MAC address of the relay client (300); and

h) forwarding the packet from the virtual client (331) to an appropriate VL-AN module (311) or SSID (321) of the relay client (300).

The method as claimed in claim 1 , wherein the relay client (300) to AP (200) operation phase includes the steps of:

a) receiving a packet at a virtual client (331) of the relay client (300); b) setting the modified transmitter MAC address by the virtual client (331);

c) adding the source address at the packet header by the virtual client (331);

d) forwarding the packet for transmission by the virtual client (331);

e) transmitting the packet with the modified address fields from the relay client (300) to the relay SSID interface (222) of the AP (200);

f) identifying the modified transmitter MAC address in the packet header by the AP (200);

g) acknowledging the receipt of the packet by the AP (200) to the MAC address of the relay client (300);

h) sending the packet to a virtual interface (223) of the AP (200) from the relay SSID interface (222) based on the modified transmitter MAC address; and

i) forwarding the packet from the virtual interface (223) to an appropriate VLAN module (211) or SSID (221) of the AP (200).