CN101873357A

CN101873357A - Method for automatically discovering wireless access points

Info

Publication number: CN101873357A
Application number: CN 201010183670
Authority: CN
Inventors: 金万贵; 龚浩敏
Original assignee: SHANGHAI HONGMEI COMMUNICATION EQUIPMENT CO Ltd
Current assignee: SHANGHAI HONGMEI COMMUNICATION EQUIPMENT CO Ltd
Priority date: 2010-05-24
Filing date: 2010-05-24
Publication date: 2010-10-27

Abstract

The invention discloses a method for automatically discovering wireless access points, which comprises the following steps that: (1) after receiving a DHCP request response carrying a gateway IP address, a wireless access point without a return module sends a PING message to a gateway to confirm delay or round trip delay; (2) the wireless access point inserts a string of code order into the PING message carrying the round trip delay; and (3) a wireless access point with a return module senses PING messages sent by adjacent wireless access points, and a wireless access point finally connected is determined according to the length of the round trip delay RTD. The method does not need manual intervention, and reduces the network layout and the workload of management, operation and maintenance.

Description

A kind of automatic discovering method of WAP (wireless access point)

Technical field

The present invention relates to a kind of wireless connection method of equipment, relate in particular to the automatic discovering method of WAP (wireless access point) in a kind of WLAN (wireless local area network).

Background technology

In Wireless MESH network, the main effect of WAP (wireless access point) (AP) is that wireless network is inserted core net, secondly each terminal equipment that links to each other with wireless router is linked together, make the terminal equipment that wireless network card is housed to share the resource of core net by AP.Traditional MESH network can only provide limited autgmentability, and one or more new AP adds fashionablely in network, need carry out the manual of each equipment and be provided with, and is very inconvenient.

Summary of the invention

In order to overcome above-mentioned defective, the object of the present invention is to provide the automatic discovering method of the WAP (wireless access point) in a kind of WLAN (wireless local area network).This method has guaranteed any because network element is increased or removes the measure that the network topology change that causes can be detected the line correlation of going forward side by side immediately, guarantees that network always is in optimum performance and running status.

For achieving the above object, technical scheme of the present invention is as follows: a kind of automatic discovering method of WAP (wireless access point) comprises the steps:

(1) WAP (wireless access point) that does not have the backhaul module sends PING message to gateway and confirms time delay or round-trip delay after the DHCP request of receiving the band gateway ip address is answered;

(2) the described WAP (wireless access point) of step 1 is inserted string of code order in having the PING message of round-trip delay;

(3) the PING message that the described WAP (wireless access point) of its contiguous step 1 is sent of the WAP (wireless access point) with backhaul module is detected, seek sign indicating number preface wherein, if described backhaul module only detects the PING message of a tape code preface, described backhaul module is connected with the WAP (wireless access point) that sends this message; If described backhaul module detects the PING message more than a tape code preface, comparison procedure of described backhaul module operation finally is connected to the WAP (wireless access point) with minimum round-trip delay.

Described backhaul module needs to know the round-trip delay of described WAP (wireless access point) to described gateway before moving described comparison procedure, and the received signal strength indicator value of described WAP (wireless access point) signal strength signal intensity.

The present invention is specifically after WAP (wireless access point) starts, each module in this access point is found automatically mutually and is determined separately functions such as mode of operation, intelligent scanning channel automatically, need not to carry out the manual configuration of each equipment, do not need manual intervention, reduced the live load of network design and management O﹠M.

Description of drawings

Fig. 1 represents not have the schematic diagram of the WAP (wireless access point) of backhaul module to the WAP (wireless access point) transmission PING message with backhaul module.

Fig. 2 is WAP (wireless access point) FSM (finite state machine) schematic diagram.

Fig. 3 is according to the question blank of receiving S meter measuring and calculating link bit rate.

Embodiment

Below in conjunction with accompanying drawing specific implementation process of the present invention is further described:

When DHCP (Dynamic HostConfiguration Protocol, dynamic host allocation protocol) the request answer that WAP (wireless access point) is received the band gateway ip address, its can send PING message to gateway confirm time-delay or round trip delay time.Each access point will be attempted carrying out bridge function, and the message between AP and gateway will be sought routed path according to the topological structure of real network between a plurality of WAP (wireless access point), and prerequisite is that all AP access points of receiving dhcp reply do not have the backhaul module.By the agreement of using IEEE802.11 to describe, AP can insert a string special sign indicating number preface in having the PING message of round-trip delay, and the sign indicating number preface can be the information field that is not used in the probing response frame, and purpose is in order to seek the round-trip delay of AP.

Referring to Fig. 1, in this process, other has backhaul module (BH, Backhaul) WAP (wireless access point) begins its adjacent access point AP is detected the sign indicating number preface message of wanting to find that string special, if backhaul module BH only detects a particular message, it can be connected with the AP that sends this message immediately; If backhaul module BH detects the particular message more than, it can move a comparison procedure and decide to be connected to which AP on earth, and the information that needs to collect before the operation comparison program comprises:

(1) AP is to the round-trip delay (RTD, Round-Trip Delay Time) of gateway;

(2) RSSI of access point signals intensity (the signal strength signal intensity indication of reception) value.

According to the RSSI value of a plurality of access point AP, backhaul module BH will calculate the round-trip delay that is connected to the diverse access point AP that receives the specific code preface, judge the access point position of short round-trip delay from the result who obtains, and this measuring and calculating step is carried out constantly.

Especially, for the value (generally being accurate to microsecond) that records RTD, access point AP can be converted to RSSI the predicted value of link bit rate according to question blank, question blank is referring to Fig. 3, first classifies wireless technology as, second classifies the different pieces of information speed number that each wireless technology is supported as, and normal data rates is in each case shown in all the other tabulations, and unit is a mbit/.

The value of supposing RSSI is between 0 to 60, and WAP (wireless access point) uses RSSI/MaxIndex to obtain the link bit value as index, and the RTD that WAP (wireless access point) calculates respective link uses the frame of 1500 bytes, observes following formula:

RTD=AP_RTD+1500*8*2/ (link bit value)

Here, the AP that obtains minimum RTD value is the optimum AP that the backhaul module will be looked for.

Parameter declaration among Fig. 2:

Init: init state machine

S: selected AP

C: candidate AP

N: new AP

I_C_cntr: incremental candidate confidence counter

C_cntr--: degression type candidate confidence counter

ST: gated counter produces the force_sel incident during excess of stroke

_ stopST: stop gated counter

PosInfo: comprise the report of the discovery agreement generation of stack name

SetStkName: the stack name is set

Rcv_rport: wireless scanning result

Rcv_logic: wireless scan report process produces new events

Rcv_SEL_AP: the highest selected AP of score in wireless scan report

Rcv_NEW_AP: the highest new AP of score in wireless scan report

Rcv_CAN_AP: the highest candidate AP of score in wireless scan report

Next: internal event

Link_lost: represent wireless chain rupture

Force_sel: safety is selected timer, and a plurality of AP have same mark

Max: the maximum of distributing variable

Instantiation, referring to Fig. 2:

(1) be in the Down state, respond the PosInfo incident, the local state of FSM initialization, counter also writes down the circulation of storehouse title to avoid occurring;

(2) be in the Down state, respond the Rcv_rport incident, FSM carries out the Next incident and carries out and understand the semantic rcv_logic of report, carry out the back and produce following incident: rcv_SEL_AP, rcv_NEW_AP or rcv_CAN_AP, since do not have candidate AP at this point, can produce the rcv_NEW_AP incident;

(3) being in the Down state carries out the Next incident and can cause FSM and state is changed to AP_DETECTED (row 1) and open and select timer ST (Selection Timer);

(4) be in the AP_DETECTED state, as responding the rcv_NEW_AP incident, FSM can stop current any candidate AP, and adopt new AP, and no matter how confidence index device (confidence counter) the C_cntr current state of this candidate all is changed to 1 with it as better candidate;

(5) be in the AP_DETECTED state, as responding the Rcv_rport incident, FSM carries out rcv_logic, produces a rcv_CAN_AP incident;

(6) be in the AP_DETECTED state, as responding the rcv_CAN_AP incident, FSM will increase candidate confidence counter and confirm that it finishes, if i.e. i_C_cntr==max, FSM will produce a Next incident;

(7) be in the AP_DETECTED state, as responding the rcv_SEL_AP incident, FSM will remove candidate confidence counter;

(8) be in the AP_DETECTED state, as responding the Next incident, FSM with candidate AP as selected AP, switch to the AP_SELECTED state and stop gated counter (_ stopST).

The connection failure of AP module or remove and can cause a link_lost incident makes the backhaul module restart to carry out above-mentioned steps until finding a new optimum AP.

Claims

1. the automatic discovering method of a WAP (wireless access point) is characterized in that, comprises the steps:

2. the automatic discovering method of WAP (wireless access point) according to claim 1, it is characterized in that, described backhaul module needs to know the round-trip delay of described WAP (wireless access point) to described gateway before moving described comparison procedure, and the received signal strength indicator value of described WAP (wireless access point) signal strength signal intensity.