(19)
`
`(12)
`
`Pate nta mt
`Europfiisches
`European
`Pate nt Office
`Offi ce européen
`
`des brevets (11)
`
`EP 2 600 585 A1
`
`EUROPEAN PATENT APPLICATION
`published in accordance with Art. 153(4) EPC
`
`(43) Date of publication:
`05.06.2013 Bulletin 2013/23
`
`(51) Int Cl.:
`H04L 29/06 (2006-01)
`
`(21) Application number: 11777238.4
`
`(22) Date of filing: 24.05.2011
`
`(86) International application number:
`PCT/CN2011I074586
`
`(87) International publication number:
`WO 2011/137819 (10.11.2011 Gazette 2011/45)
`
`(84) Designated Contracting States:
`AL AT BE BG CH CY CZ DE DK EE ES FI FR GB
`GR HR HU IE IS IT LI LT LU LV MC MK MT NL N0
`PL PT RO RS SE SI SK SM TR
`
`(30) Priority: 26.07.2010 CN 201010246659
`
`(71) Applicant: Huawei Technologies Co., Ltd.
`Shenzhen, Guangdong 518129 (CN)
`
`(72) Inventors:
`- B|,Xiaoyu
`Shenzhen
`
`- XIE, Lei
`Shenzhen
`
`Guangdong 518129 (CN)
`- CHEN, Jing
`Shenzhen
`
`Guangdong 518129 (CN)
`
`(74) Representative: Epping - Hermann - Fischer
`Patentanwaltsgesellschaft mbH
`RidlerstraBe 55
`
`80339 Miinchen (DE)
`
`Guangdong 518129 (CN)
`
`
`(54)
`
`TIME MESSAGE PROCESSING METHOD, APPARATUS AND SYSTEM
`
`A time message processing method, apparatus
`(57)
`and system are provided by the embodiments of the
`present. The method includes: receiving a time message
`transmitted from a transmitter; determining whether the
`time message is an event message according to the iden-
`tifier information in the time message, wherein the iden-
`tifier information is the information carried in the field
`
`which is not encrypted with the Internet protocol security
`by the transmitter. With the method, apparatus and sys—
`
`tern provided by the embodiments of the present, after
`receiving the time message, the time message receiver
`can directly determine whether the time message is the
`event message according to the identifier information
`carried in the field which is not encrypted by the Internet
`protocol security in the time message, without any de-
`cryption, thereby solving the problem in the prior art that
`it cannot be determined whether the time message is an
`event message.
`
`101
`
`
`
`
` Receiving a time message
` Determining whether the received
`
`
`encrypted with lPsec
`
`time message is an event message
`according to identifier information in
`the received time message, wherein the
`identifier information is the information
`carried in a field which is not
`
`FIG.1
`
`
`
`Printed by Jouve, 75001 PARIS (FR)
`
`EP2600585A1
`
`

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`1
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`EP 2 600 585 A1
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`2
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`Description
`
`Summary
`
`Cross-Reference to Related Application
`
`[0001] This application claims priority toa Chinese Pat-
`ent Application No. 201010246659] filed to the State
`Intellectual Property Office of the PRC on July 26, 2010,
`which is hereby incorporated by reference in its entirety.
`
`Field of the Technology
`
`[0002] The embodiments of the invention relate to the
`field of synchronization technology, and particularly, to a
`time message processing method, apparatus and sys—
`tem.
`
`Background
`
`[0003] There are always the requirements of time syn-
`chronization orfrequency synchronization in the commu-
`nication network, and currently two modes are available
`for time synchronization or frequency synchronization:
`Network Time Protocol (NTP) and PTP (Precision Time
`Protocol). The PTP is the abbreviation of IEEE1588V2,
`which is a protocol proposed by the Institute of Electrical
`and Electronic Engineers (IEEE) for frequency synchro-
`nization in the packet network, and its full name is "pre-
`cision clock synchronization protocol
`for networked
`measurement and control systems". For example, in the
`3GPP Long Term Evolution (LTE) network, since the Us-
`er Equipment (UE) needs to switch between eNBs, syn-
`chronization is required between the eNBs. In the Fre-
`quency Division Duplex(FDD) mode,frequencysynchro-
`nization shall be kept between the eNBs, and both the
`PTP and the NTP can support frequency synchroniza-
`tion.
`
`[0004] The NTP is a standard Internet protocol for time
`synchronization in the Internet. The purpose of the NTP
`is to synchronize the computer time to some time stand-
`ards. The time synchronization means limiting the devi-
`ation of the time information maintained by various com-
`munication devices or computer devices in the network
`within a range small enough (e.g., 100 ms), and this proc-
`ess is referred to as time synchronization.
`[0005] When lEEE1588V2 is employed for time syn-
`chronization between the eNB and the clock server, usu-
`ally there are two connection modes between the eNB
`and the clock server: one is that the eNB directly estab—
`lishes an Internet protocol security (lPsec) connection
`with the clock server, the other is that the eNB establishes
`an IPsec connection with the clock server through a Se-
`curity Gateway (SGW).
`[0006]
`In the prior art, when the system adopts the
`IPsec technology to perform an encryption of time syn-
`chronization or frequency synchronization for the PTP,
`the time message receiver may not determine whether
`a time message is an event message after receiving the
`time message.
`
`[0007] The embodiments of the present invention pro-
`vide a time message processing method, apparatus and
`system, so as to solve the problem in the prior art that
`the time message receiver cannot determine whether a
`time message is an event message after receiving the
`time message.
`[0008] The embodiments of the present invention pro-
`vide a time message processing method, including:
`
`receiving a time message transmitted from a trans—
`mitter; and
`determining whether the time message is an event
`message according to identifier information in the
`time message, wherein the identifier information is
`the information carried in a field which is not encrypt-
`ed with an Internet protocol security (lPsec) by the
`transmitter.
`
`[0009] The embodiments of the present invention fur-
`ther provide a time message processing method, includ-
`Ing:
`
`carrying identifier information in a time message en—
`crypted by an Internet protocol security (IPsec),
`wherein the identifier information is carried by afield
`of the time message which is not encrypted with the
`IPsec; and
`transmitting the time message.
`
`[0010] The embodiments of the present invention fur-
`ther provide a time message processing apparatus of a
`receiver, including:
`
`a receiving module, configured to receive a time
`message; and
`a determining module, configured to determine
`whether the time message received by the receiving
`module is an event message, according to identifier
`information carried in a field of the time message
`which is not encrypted by an Internet protocol secu-
`rity (lPsec).
`
`[0011] The embodiments of the present invention fur-
`ther provide a time message processing apparatus of a
`transmitter, including:
`
`a carrying module, configured to carry identifier in—
`formation in a time message encrypted byan Internet
`protocol security (IPsec), wherein the identifier infor-
`mation is carried in afield of thetime message which
`is not encrypted with the IPsec; and
`a transmitting module, configured to transmit the
`time message processed by the carrying module.
`
`[0012] The embodiments of the present invention fur-
`ther provide a time message processing system, com-
`
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`3
`
`EP 2 600 585 A1
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`4
`
`F'g. 17 illustrates a schematic diagram of another
`IPv6 extended header format that carries a times—
`
`prising the aforementioned time message processing ap—
`paratus ofthe transmitter and the time message process—
`ing apparatus of the receiver.
`[0013]
`In the method, apparatus and system provided
`by the embodiments of the present invention, the identi-
`fier information is carried in the field of the time message
`which is notencrypted with the lPsec. Thus, after receiv-
`ing the time message, the receiver of the time message
`can directly determine whether the time message is an
`event message according to the identifier information
`without any decryption, thereby solving the problem that
`the receiver of the time message cannot determine
`whether the received ti me message is an event message.
`
`Brief Description of the Drawings
`
`[0014]
`
`illustrates a flowchart of Embodiment 1 of a
`Fig. 1
`time message processing method according to the
`present invention;
`Fig. 2 illustrates a flowchart of Embodiment 2 of a
`time message processing method according to the
`present invention;
`Fig. 3 illustrates a schematic diagram of an AAD for—
`mat;
`Fig. 4 illustrates aschematicdiagram ofanotherAAD
`format;
`Fig. 5 illustrates a schematic diagram of an AAD for-
`mat that carries a timestam p;
`Fig. 6 illustrates a schematic diagram of an AAD for-
`mat added with an algorithm identifier;
`Fig. 7 illustrates a flowchart of Embodiment 3 of a
`time message processing method according to the
`present invention;
`Fig. 8 illustrates a flowchart of time synchronization
`between an eNB and a clock server;
`Fig. 9 illustrates a schematic diagram of a timestamp
`processing method according to an embodiment of
`the present invention;
`Fig. 10 illustrates a schematic diagram of an ESP
`header format that carries message identifier infor-
`mation;
`Fig. 11 illustrates a schematic diagram of an ESP
`header format that carries a timestamp;
`Fig. 12 illustrates a flowchart of Embodiment 4 of a
`time message processing method according to the
`present invention;
`Fig. 13 illustrates a schematic diagram of an ESP
`header having sub-formats;
`Fig. 14 illustrates a schematic diagram of an ESP
`header that carries a timestamp and has sub-for-
`mats;
`Fig. 15 illustrates a flowchart of Embodiment 5 of a
`time message processing method according to the
`present invention;
`Fig. 16 illustrates a schematic diagram of an va6
`extended header format that carries a timestamp;
`
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`"NEXUTI'OWTI'OED‘H‘O(D(I)(D 5 ,_..
`
`tamp;
`F'g. 18 illustrates a flowchart of Embodiment 6 of a
`time message processing method according to the
`present 'nvention;
`F'g. 19 illustrates a flowchart of Embodiment 8 of a
`time message processing method according to the
`present 'nvention;
`F'g. 20 illustrates a flowchart of Embodiment 9 of a
`time message processing method according to the
`resent 'nvention;
`'g. 21 ilustrates a flowchart of Embodiment 10 of
`time message processing method according to the
`resent 'nvention;
`'g. 22 ilustrates a flowchart of Embodiment 11 of
`time message processing method according to the
`resent 'nvention;
`'g. 23 ilustrates a flowchart of Embodiment 12 of
`time message processing method according to the
`'nvention;
`'g. 24 illustrates a structure diagram of an embod-
`iment ofa time message processing apparatus of a
`transmitter according to the present invention;
`F'g. 25 illustrates a structure diagram of an Embod—
`iment of a time message processing apparatus of a
`receiver according to the present invention.
`
`Detailed Description
`
`In the embodiments of the present invention,
`[0015]
`the PTP is taken as an example to illustrate a secure
`processing method when time synchronization is protect-
`ed through lPsec, wherein the event message is not lim-
`ited to the PTP event message, i.e., not limited to the
`event message protocol in the PTP, and it may be any
`event message in the protocol that satisfies the condi—
`tions and carries time information, such as NTP.
`[0016] Theimplementationsoftheembodimentsofthe
`present invention are detailedly described as follows,
`mainly by taking two scenarios as examples: one is that
`the eNB directly establishes an lPsec connection with
`the clock server, the other is that the eNB establishes an
`lPsec connection with the clock serverthrough an SGW.
`
`Scenario 1: the eNB establishes an lPsec connection
`
`with the clock server through the SGW
`
`illustrates a flowchart of Embodiment 1
`1
`Fig.
`[0017]
`of a time message processing method according to the
`present invention, including:
`
`Step 101: receiving atime messagetransmitted from
`a transmitter. In the embodiment of the present in-
`vention, the time message is a message used by the
`system for time synchronization or frequency syn-
`chronization. The transmitter may be the SGW or
`the eNB.
`
`

`

`5
`
`EP 2 600 585 A1
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`6
`
`In a case where the eNB directly establishes an
`lPsec connection with the clock server, the transmit—
`ter may be the clock server or the eNB.
`Step 102: determining whether the received time
`message is an event message according to identifier
`information therein. The identifier information is the
`
`information of the transmitter carried by the field
`which is not encrypted with the lPsec.
`
`[0018] The identifier information at least may include
`one of a timestamp, a User Datagram Protocol (UDP)
`port number and a message type.
`[0019]
`In step 102,
`it can be specifically determined
`whether the received time message is an event message
`according to the information such as the timestamp, the
`UDP port number and the message type.
`[0020]
`If the identifier information of the time message
`includes a timestamp, the receiver of the time message
`can determine that the time message is an event mes-
`sage.
`[0021] Alternatively, if the identifier information of the
`time message includes a preset UDP port number, the
`receiver of the time message can determine thatthe time
`message is an event message. The transmitter and the
`receiver of the time message may negotiate in advance
`to set UDP port numbers (e.g., 319 and 320) correspond-
`ing to the event message. Thus, after receiving the time
`message, if the receiver of the time message notes that
`the UDP port number in the unencrypted field ofthe time
`message is 319, then it can determine that the time mes-
`sage is an event message.
`[0022] Alternatively, if the identifier information of the
`time message includes a preset message type, the re-
`ceiver ofthe time message determines thatthe time mes-
`sage is an event message. The transmitter and the re-
`ceiver of the time message may negotiate in advance to
`set message types corresponding to the event message.
`After receiving the time message, if the receiver of the
`time message notes that the message type in the unen-
`crypted field of the time message is the preset message
`type, then it can determine that the time message is an
`event message.
`[0023]
`In this embodiment, the identifier information is
`carried in the field of the time message, which is not en-
`crypted with the lPsec. Thus, after receiving the time
`message, the receiver ofthe time message can directly
`determine whether the time message is an event mes-
`sage according to the identifier information, without any
`decryption, thereby solving the problem thatthe receiver
`of the time message cannot determine whether the re-
`ceived time message is an event message.
`[0024] On the basis of the technical solution ofthe em-
`bodiment as illustrated in Fig. 1, the method may further
`include the step: ifthe received time message is an event
`message, acquiring the current timing and taking it as
`the timing of receiving the time message.
`[0025]
`In this embodiment, it is determined in step 102
`whether the received ti me message is an event message,
`
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`and if so, acquiring the current timing and taking it as the
`timing of receiving the time message, rather than acquir—
`ing receiving timings of all the received time messages.
`After receiving the time message, it takes very short time
`to determine whether the time message is an event mes-
`sage according to the identifier information. Thus, after
`determining that the received time message is an event
`message, by immediately acquiring the current timing
`and taking it as the timing of receiving the time message,
`the acquired current timing approximates to the actual
`receiving timing of the time message, thereby meeting
`the accuracy requirementfor subsequentfrequency syn—
`chronization or time synchronization. Therefore, it only
`needs to acquire the receiving timing of the event mes—
`sage rather than acquiring receiving timings of all the
`received time messages, thereby reducing the resources
`required for storing and maintaining the receiving timing
`ofthe time message, and improving the network perform-
`ance.
`
`[0026] On the basis of the technical solution of the
`aforementioned embodiment, the method may further in-
`clude the step: if the received time message is not an
`event message, the current timing needs not to be ac-
`quired, i.e., it is unnecessary to acquire the receiving tim—
`ing of the time message, thereby reducing the resources
`required for storing and maintaining the receiving timing
`ofthe time message, and improving the network perform-
`ance.
`
`[0027] Alternatively, after receiving the time messag-
`es, receiving timings of all the time messages are tem-
`porarily recorded. After it is determined that a time mes-
`sage is an event message, the receiving timings of the
`time messages which are not event messages are im-
`mediately discarded, thereby ensuring the accuracy of
`the receiving timing, reducing the resources required for
`storing and maintaining the receiving timing when a time
`message is not an event message, and improving the
`network performance.
`[0028]
`In the embodiment of the present invention, in-
`tegrity checks may be carried out for the received time
`message and the identifier information in the time mes-
`sage.
`Specifically, after determining that a time mes-
`[0029]
`sage is an event message and before acquiring the cur-
`rent timing, the integrity for the identifier information in
`the time message is checked. Alternatively, after receiv-
`ing a time message transmitted from the transmitter and
`before determining whether the time message is an event
`message, the integrity for the identifier information in the
`time message is checked.
`[0030] After determining that the time message is an
`event message and before acquiring the current timing,
`the integrity check for the time message is performed by
`using the input content the same as that employed by
`the transmitter of the time message for an integrity pro-
`tection ofthe time message. Alternatively, after receiving
`the time message transmitted from the transmitter and
`before determining whether the time message is an event
`
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`EP 2 600 585 A1
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`8
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`message, the integrity checkforthetime message is per—
`formed by using the input content the same as that em—
`ployed by the transmitter of the time message for an in-
`tegrity protection of the time message.
`[0031]
`In various embodiments of the present inven-
`tion, the field which is not encrypted with the lPsec may
`be carried in Additional Authentication Data (AAD), En-
`capsulating Security Payload (ESP) header or Internet
`protocol version 6 (IPv6) extended header.
`[0032]
`Fig. 2 illustrates a flowchart of Embodiment 2
`of a time message processing method according to the
`present invention, including:
`
`Step 201: carrying identifier information in a time
`message encrypted with the lPsec, the identifier in-
`formation being carried by a field which is not en-
`crypted with the lPsec in the time message.
`Step 202: transmitting the time message.
`
`In various embodiments of the present inven-
`[0033]
`tion, the identifier information is a plaintext notencrypted
`with the lPsec, and can be carried by the field not en-
`crypted with the lPsec, such as AAD, ESP header and
`va6 extended header ofthe time message.
`[0034] The following embodiment ofthe present inven—
`tion is described through an example in which the iden-
`tifier information is a timestamp.
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`1. The identifier information notencrypted with the lPsec
`is carried in the AAD
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`
`Fig. 3 illustrates a schematic diagram ofan AAD
`[0035]
`format, and Fig. 4 illustrates a schematic diagram of an-
`other AAD format.
`In the AAD, the security parameter
`index (SPI) and the Sequence Number (SQN) are the
`contents contained by the ESP payload in RFC4303, for
`security association identification and anti—replay protec—
`tion. The SQN has 32 bits and may be extended to 64
`bits. The fields "Type" and "Length" indicate the type and
`the length of the identifier information in the AAD which
`is not encrypted with the lPsec, respectively. The AAD
`carrying the identifier information may be distinguished
`from other AAD withnot carrying the identifier information
`through one byte of 0 or 1, or a new AAD format may be
`defined directly.
`[0036]
`Fig. 5 illustrates a schematic diagram ofan AAD
`format that carries a timestamp. On the basis of the AAD
`format as illustrated in Fig. 4, the AAD is added with a
`timestamp field, a replay counter, and a Timestamp ln—
`tegrity Check Value (ICV) field.
`[0037]
`In order to prevent the timestamp from being
`tampered during the transmission, an integrity protection
`of the timestamp is required, wherein other added infor-
`mation may be included, such as all 0, all 1, length, etc.
`The algorithm negotiated bythe lPsec may actas 8 times-
`tamp integrity check algorithm, or one field may be added
`to the AAD to carry the used integrity check algorithm.
`For example, the check algorithm may calculate a hash
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`code
`authentication
`message
`based
`value
`(HMAC—SHA1) using a hash function SHA1, calculate a
`hash value based message authentication code (H MAC-
`SHA256) using a hash function SHA256, or carry the
`algorithm ID in the AAD. Fig. 6 illustrates a schematic
`diagram of an AAD format added with an algorithm ID.
`[0038] The ICV ofthe timestamp can be calculated ac-
`cording to the determined integrity check algorithm and
`key, specifically, the transmittertakes the determined key
`and the content in the AAD except the ICV as the input,
`calculate a digest by the determined integrity algorithm,
`and put the calculated digest in the ICV. The ICV shall
`be reset before the calculation. The receiver uses the
`
`same integrity check algorithm and key to calculate the
`digest, and compares the calculation result with the ICV
`in the received message. Ifthey are consistentwith each
`other, it means that the timestamp integrity check suc-
`ceeds; otherwise it means that the timestamp has been
`modified and the receiver shall send an error indication
`
`or discard the received message.
`[0039] Alternatively, other timestamp integrity check
`method may also be used, for example, some non-key
`check methods may be employed.
`[0040] An integrity check of other identifier information
`may also be made using a method similar to the times—
`tamp integrity check.
`[0041]
`In Figs. 5-6, the timestamp may include two
`sub-fields: Timestamp (secondsField) and Timestamp
`(nanosecondsField), which are both optional. When the
`timestamp is needed to be carried, the two sub-fields
`may be included in the AAD. Timestamp (secondsField)
`is a 32-bit unsigned integer, and Timestamp (nanosec-
`ondsField) is defined as a 48-bit unsigned integer in
`lEEE1588V2 protocol, but Timestamp (nanoseconds-
`Field) may also be defined as 64-bit.
`[0042] The Algorithm ID field is the identification of the
`employed integrity check algorithm, and the location of
`the field may be not limited to that as illustrated in Fig. 6.
`[0043] The Timestamp Integrity Check Value field
`means the value ofthe employed ICV.
`[0044]
`Fig. 7 illustrates a flowchart of Embodiment 3
`of a time message processing method according to the
`present invention, wherein the identifier information not
`encrypted with the lPsec is carried by an AAD in the mes-
`sage. The method specifically includes:
`
`Step 301: a clock server performs an IP layer
`processing for the message by adding an IP header
`and a UDP header thereto, then performs an MAC
`layer processing by adding an MAC header to the
`message, and carrying a transmitting timing T1 of
`the message in the message before performing a
`PHY layer processing.
`Step 302: the clock server transmits the message to
`an SGW in form of plaintext.
`Step 303: the SGW extracts or copies T1 from the
`received message.
`Step 304: the SGW carries T1 in the AAD not en-
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`EP 2 600 585 A1
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`crypted with the |Psec in the message, and performs
`an integrity protection for T1, i.e., calculating an ICV
`of timestamp T1 and putting it in the Timestamp ln-
`tegrity Check Value field, and then performing an
`integrity protection for the message, thus a check
`value of the message is calculated, as indicated by
`the |Psec.|CV field in Fig. 7. In this step, |Psec.|CV
`is an abbreviation ofthe |Psec Integrity Check Value.
`The SGW extracts T1 from the received message
`and carries T1 in the AAD withoutchanging the band-
`width, but the message integrity is destroyed. If the
`SGW copies T1 from the received message, the
`message integrity will not be destroyed while the
`bandwidth is increased. Thus, the two ways for ac—
`quiring T1 both have their advantages and disadvan-
`tages.
`Step 305: the SGW performs an MAC layer process-
`ing to add an MAC header to the message.
`Step 306: the SGW transmits the message to an
`eNB.
`
`Step 307: the eNB determines whether the received
`message is an event message based on the AAD
`not encrypted with the |Psec in the message, and if
`so, performs a timestamp integrity check or a mes—
`sage integrity check according to the information in
`the AAD and the IP packet, so as to acquire the cur-
`rent timing T2 and the transmitting timing T1 in the
`message, and take the current timing T2 as the tim-
`ing of receiving the message. The eNB may also
`perform a timestamp integrity check and a message
`integrity check for the time message, after receiving
`the time message and before determining whether
`it is an event message.
`
`[0045] After the timestamp integrity check and the
`message integrity check succeed, the eNB may perform
`frequency synchronization and time synchronization with
`the clock server according to T2 and T1.
`[0046]
`Fig. 9 illustratesa schematicdiagram ofatimes-
`tamp processing method according to an embodiment of
`the present invention. A timestamp is generated when a
`message passes through a point defined by a protocol
`stack in the node. The point may be located at the appli-
`cation layer (PointA in Fig. 9), the kernel or the interrupt
`service routine (Point B in Fig. 9), or the PHY layer of the
`protocol stack (Point C in Fig. 9). The timing error caused
`by a delay jitter occurring in passing through the next
`layer will be smaller when the point is closer to the PHY
`layer. In order to ensure the time accuracy, 1588v2 pro—
`tocol recommends marking the timestamp at a location
`between the PHY layer and the MAC layer.
`[0047]
`In the embodiment as illustrated in Fig. 7, mes-
`sage identifier information is carried in the message AAD,
`and the eNB can determine whether the message is an
`event message once it is received. When the message
`is an event message, the current timing is acquired and
`taken as the receiving timing ofthe message, rather than
`acquiring receiving timings of all messages, thereby im-
`
`proving the network performance.
`
`2. The message identifier information notencrypted with
`the |Psec is carried in the ESP header
`
`[0048] The ESP header includes two fields, i.e., SPI
`and SQN, which are under integrity protection while going
`beyond the scope of |Psec encryption protection. The
`identifier information may be carried in the ESP header.
`The ESP headercarrying the identifier information should
`be distinguished from the conventional ESP header, and
`the ESP header carrying the identifier information may
`be identified by various specific identifiers such as all 0
`byte, all 1 byte, etc. Since the identifier information may
`be other identifiers such as UDP port number, message
`type, etc. in addition to the timestamp, the fields Type,
`Length and Authentication Payload can be defined in the
`extended field of the ESP header.
`
`Fig. 10 illustrates a schematic diagram of an
`[0049]
`ESP header format that carries message identifier infor-
`mation, wherein the field Type may include 4 or 8 bits,
`e.g., the type ofthe timestamp may be marked as 1, Le,
`Type=1. The field Length identifies a length of content
`under timestamp integrity protection but without encryp—
`tion protection. The range of the plaintext can be more
`explicitly identified by increasing the field Length, which
`may include 8 or 16 bits. The Authentication Payload
`includes a value ofauthentication payload (e.g., a times-
`tamp), an authentication algorithm or identifier and a
`timestamp integrity check value.
`[0050] The content from the payload data to the next
`header is the content under encryption protection in the
`original ESP payload.
`[0051]
`Fig. 11 illustrates a schematic diagram of an
`ESP header format that carries a timestam p, wherein the
`value ofthe field Type is 1,i.e., Type=1 ; the two sub—fields
`of the field Timestamp, i.e., secondsField and nanosec—
`ondsField, include 32 bits and 10 bytes, respectively; the
`field Algorithm or Algorithm Identifier includes 16 or 32
`bits; and the timestamp Integrity Check Value (ICV) (op-
`tional) is related to the specific integrity check algorithm.
`[0052]
`Fig. 12 illustrates a flowchart of Embodiment 4
`of a time message processing method according to the
`present invention, wherein the identifier information not
`encrypted with the |Psec is carried in an ESP header in
`a message. The method specifically includes:
`
`Steps 501—503: the same as steps 301—303, respec—
`tively;
`Step 504: an SGW carries T1 in an ESP header
`which is notencrypted with thelPsec inthe message;
`Step 505: the SGW performs an MAC layer process-
`ing for the message to add an MAC header to the
`message;
`Step 506: the SGW transmits the message to an
`eNB;
`Step 507: the eNB determines whether the received
`message is an event message based on the ESP
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`11
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`EP2 600 585 A1
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`12
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`header of the message which is not encrypted with
`the lPsec, and if so, performs a timestamp integrity
`check and a message integrity check according to
`the information in the ESP header and the IP packet.
`The eNB may also perform the timestamp integrity
`check and the message integrity check for the time
`message, after receiving the time message and be-
`fore determining whether it is an event message.
`
`In the embodiment as illustrated in Fig. 12, the
`[0053]
`identifier information is carried in an ESP header of a
`
`message, and the eNB can determine whether the mes—
`sage is an event message once it is received. When the
`message is an event message, the current timing is ac—
`quired and taken as the receiving timing of the message,
`rather than acquiring receiving timings of all the messag-
`es, thereby improving the network performance.
`
`10
`
`15
`
`3. The identifier information notencrypted with the lPsec
`is carried in the ESP header having sub-formats
`
`20
`
`Fig. 13 illustrates a schematic diagram of an
`[0054]
`ESP header having sub-formats. The ESP header in-
`cludes a flexible AAD and an encrypted part, the flexible
`AAD defines SPI, SQN, Type, Length and Authentication
`Payload, and the encrypted part that includes Payload
`Data, Padding, Pad length and Next Header, which all
`come from the ESP payload. The ESP header also in-
`cludes a Timestamp Integrity Check Value (lCV).
`[0055] When Type=1, the message identifier informa-
`tion is a timestamp. Fig. 14 illustrates a schematic dia-
`gram ofan ESP header that carries a timestamp and has
`sub-formats. For the ESP header, when there is no other
`extended content in addition to the SPI and the SQN, the
`value of the field Type is set as maximum or invalid (all
`1), the value of the field Length is all 0, and the length of
`the field Authentication Payload is 0 (the field Type may
`also be set as all 0, or other special identifying method
`may be adopted). When there is any other message iden-
`tifier information, the values ofthe fields Type and Length
`may be non-zero.
`[0056]
`Fig. 15 illustrates a flowchart of Embodiment 5
`of a time message processing method according to the
`present invention, wherein the Type identifier not en-
`crypted with the lPsec is carried by an ESP header with
`sub-formats in the message. The method specifically in-
`cludes:
`
`Steps 601—603: the same as steps 301—303, respec—
`tively;
`Step 604: an SGW carries T1 in an ESP header
`which is not encrypted with the lPsec and has
`sub-formats in the message;
`Step 605: the SGW performs an MAC layer process-
`ing for the message to add an MAC header;
`Step 606: the SGW transmits the message to an
`eNB;
`Step 607: the eNB determines whether the received
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`message is an event message based on the ESP
`header of the message which is not encrypted with
`the lPsec and has sub-formats, and if so, performs
`a timestamp integrity check and a message integrity
`checkaccordingtothe information in the ESP header
`having sub-formats and the IP packet, so as to ac-
`quire the currenttiming T2 and take itas the receiving
`timing of the message. The eNB may also perform
`the timestamp integrity check and the message in-
`tegrity check for the time message, after receiving
`the time message and before determining whether
`it is an event message.
`
`In the embodiment as illustrated in Fig. 15, the
`[0