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ITUT分组传送技术标准

6
电信级以太网
传统以太网存在的问题
➢ 网络规模小，业务提供能力差 ➢ 缺乏带宽和QoS管理 ➢ 缺乏运营级别的保护与OAM机制 ➢ 交换机集中，星形结构网络拓扑 ➢ 缺少足够的扩展性和资源利用能力
电信科学技术第五研究所
城域以太网论坛MEF对城域以太网络从体系架构、管理、保护、QoS、业务等多方面进行了功能框架定义。
➢可扩展性：业务带宽和业务规模均可灵活扩展
➢可靠性：用户无感知的故障恢ห้องสมุดไป่ตู้，低于50ms的保护倒换
➢QoS保证：有保障的端到端业务性能，各种以太网业务， 10万条以上的业务规模，从1Mbit/s到10Gbit/s以太网
➢电信级网络管理：快速业务建立，OAM，用户网络管理
应用业务层（APP）（如：IP、MPLS等）
Abstract test Suite for Ethernet Services at the UNI
MEF21
Ethernet Service Attributes Phase 2
MEF22
User Network Interface (UNI) Requirements and MEF23 Framework
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时间 1968~1972年 1973~1980年
1980年 1990~1994年 1992~1995年 1995~1999年 1998~2000年 1999~2002年 2000~2004年 2005年~2009年
2010年~
以太网发展简要回顾
电信科学技术第五研究所
进程以太网技术原型以太网技术问世
电信级以太网也称为运营级以太网CE（Carrier Ethernet），
2005年由MEF提出，目的是把以太网变为电信运营商

ITUT X.691数据类型编解码规则中文版

外文资料11 Encoding the boolean type11.1 11.1 A value of the boolean type shall be encoded as a bit-field consistingof a single bit.11.2 The bit shall be set to 1 for TRUE and 0 for FALSE.11.3 The bit-field shall be appended to the field-list with no length determinant.12 Encoding the integer typeNOTE 1 – (Tutorial ALIGNED variant) Ranges which allow the encoding of all values into one octet or less go into a minimum-sized bit-field with no length count. Ranges which allow encoding of all values into two octets go into two octets in an Octet-aligned bit-field with no length count. Otherwise, the value is encoded into the minimum number of octets (using nonnegative-binary-integer or2's-complement-binary-integer encoding as appropriate) and a length determinant is added. In this case, ifthe integer value can be encoded in less than 127 octets (as an offset from any lower bound that might be determined), and there is no finite upper and lower bound, there is a one-octet length determinant, else the length is encoded in the fewest number of bits needed. Other cases are not of any practical interest, but are specified for completeness.NOTE 2 – (Tutorial UNALIGNED variant) Constrained integers are encoded in the fewest number of bits necessary to represent the range regardless of its size. Unconstrained integers are encoded as in Note 1.12.1 If an extension marker is present in the constraint specification of the integer type, then a single bit shall be added to the field-list in a bit-field of length one. The bit shall be set to 1 if the value to be encoded is not within the range of the extension root, and zero otherwise. In the former case, the value shall be added to the field-list as an unconstrained integer value, as specified in 12.2.4 to 12.2.6, completing this procedure. In the latter case, the value shall be encoded as if the extension marker is not present.12.2 If an extension marker is not present in the constraint specification of the integer type, then the following applies.12.2.1 If PER-visible constraints restrict the integer value to a single value, then there shall be no addition to the field-list, completing these procedures.12.2.2 If PER-visible constraints restrict the integer value to be a constrained whole number, then it shall be converted to a field according to the procedures of 10.5 (encoding of a constrained whole number), and the proceduresof 12.2.5 to 12.2.6 shall then be applied.12.2.3 If PER-visible constraints restrict the integer value to be asemi-constrained whole number, then it shall be converted to a field according to the procedures of 10.7 (encoding of a semi-constrained whole number), and the procedures of 12.2.6 shall then be applied.12.2.4 If PER-visible constraints do not restrict the integer to be either a constrained or a semi-constrained whole number, then it shall be converted to a field according to the procedures of 10.8 (encoding of an unconstrained whole number), and the procedures of 12.2.6 shall then be applied.12.2.5 If the procedures invoked to encode the integer value into a field did not produce the indefinite length case (see 10.5.7.4 and 10.8.2), then that field shall be appended to the field-list completing these procedures.12.2.6 Otherwise, (the indefinite length case) the procedures of 10.9 shall be invoked to append the field to the field-list preceded by one of the following:a) A constrained length determinant "len" (as determined by 10.5.7.4) ifPER-visible constraints restrict the type with finite upper and lower bounds and, if the type is extensible, the value lies within the range of the extension root. The lower bound "lb" used in the length determinant shall be 1, and the upper bound "ub" shall be the count of the number of octets required to hold the range of the integer value.NOTE – The encoding of the value "foo INTEGER (256..1234567) ::= 256" would thus be encoded as 00xxxxxx00000000, where each 'x' represents a zero pad bit that may or may not be present depending on where within the octet the length occurs (e.g., the encoding is 00 xxxxxx 00000000 if the length starts on an octet boundary, and 00 00000000 if it starts with the two least signigicant bits (bits 2 and 1) of an octet).b) An unconstrained length determinant equal to "len" (as determined by 10.7 and 10.8) if PER-visible constraints do not restrict the type with finite upper and lower bounds, or if the type is extensible and the value does not lie within the range of the extension root.13 Encoding the enumerated typeNOTE – (Tutorial) An enumerated type without an extension marker is encoded as if it were a constrained integer whose subtype constraint does not contain an extension marker. This means that an enumerated type will almost always in practice be encoded as a bit-field in the smallest number of bits needed to express every enumeration. In the presence of an extension marker, it is encoded as a normally small non-negative whole number if the value is not in the extension root.13.1 The enumerations in the enumeration root shall be sorted into ascending order by their enumeration value, and shall then be assigned an enumeration index starting with zero for the first enumeration, one for the second, and so on up to the last enumeration in the sorted list. The extension additions (which are always defined in ascending order) shall be assigned an enumeration index starting with zero for the first enumeration, one for the second, and so on up to the last enumeration in the extension additions.NOTE – ITU-T Rec. X.680 | ISO/IEC 8824-1 requires that each successive extension addition shall have a greater enumeration value than the last.13.2 If the extension marker is absent in the definition of the enumerated type, then the enumeration index shall be encoded. Its encoding shall be as though it were a value of a constrained integer type for which there is no extension marker present, where the lower bound is 0 and the upper bound is the largest enumeration index associated with the type, completing this procedure.13.3 If the extension marker is present, then a single bit shall be added to the field-list in a bit-field of length one. The bit shall be set to 1 if the value to be encoded is not within the extension root, and zero otherwise. In the former case, the enumeration additions shall be sorted according to 13.1 and the value shall be added to the field-list as a normally small non-negative whole number whose value is the enumeration index of the additional enumeration and with "lb" set to 0, completing this procedure. In the latter case, the value shall be encoded as if the extension marker is not present, as specified in 13.2.NOTE – There are no PER-visible constraints that can be applied to an enumerated type that are visible to these encoding rules.14 Encoding the real typeNOTE – (Tutorial) A real uses the contents octets of CER/DER preceded by a length determinant that will in practice be a single octet.14.1 If the base of the abstract value is 10, then the base of the encoded value shall be 10, and if the base of the abstract value is 2 the base of the encoded value shall be 2.14.2 The encoding of REAL specified for CER and DER in ITU-T Rec. X.690 | ISO/IEC 8825-1 shall be applied to give a bit-field (octet-aligned in the ALIGNED variant) which is the contents octets of the CER/DER encoding. The contents octets of this encoding consists of "n" (say) octets and is placed in a bit-field (octet-aligned in the ALIGNED variant) of "n" octets. The procedures of 10.9 shall be invoked to append this bit-field (octet-aligned in the ALIGNED variant) of "n" octets to thefield-list, preceded by an unconstrained length determinant equal to "n".15 Encoding the bitstring typeNOTE – (Tutorial) Bitstrings constrained to a fixed length less than or equal to 16 bits do not cause octet alignment. Larger bitstrings are octet-aligned in the ALIGNED variant. If the length is fixed by constraints and the upper bound is less than 64K, there is no explicit length encoding, otherwise a length encoding is included which can take any of the forms specified earlier for length encodings, including fragmentation for large bit strings.15.1 PER-visible constraints can only constrain the length of the bitstring.15.2 Where there are no PER-visible constraints and ITU-T Rec. X.680 |ISO/IEC 8824-1, 21.7, applies the value shall be encoded with no trailing 0 bits (note that this means that a value with no 1 bits is always encoded as an empty bit string).15.3 Where there is a PER-visible constraint and ITU-T Rec. X.680 | ISO/IEC 8824-1, 21.7, applies (i.e. the bitstring type is defined with a "NamedBitList"), the value shall be encoded with trailing 0 bits added or removed as necessary to ensure that the size of the transmitted value is the smallest size capable of carrying this value and satisfies the effective size constraint.15.4 Let the maximum number of bits in the bitstring (as determined byPER-visible constraints on the length) be ub" and the minimum number of bits be "lb". If there is no finite maximum we say that "ub" is unset. If there is no constraint on the minimum, then "lb" has the value zero. Let the length of the actual bit string value to be encoded be "n" bits.15.5 When a bitstring value is placed in a bit-field as specified in 15.6 to 15.11, the leading bit of the bitstring value shall be placed in the leading bit of the bit-field,and the trailing bit of the bitstring value shall be placed in the trailing bit of thebit-field.15.6 If an extension marker is present in the size constraint specification of the bitstring type, a single bit shall be added to the field-list in a bit-field of length one. The bit shall be set to 1 if the length of this encoding is not within the range of the extension root, and zero otherwise. In the former case, 15.11 shall be invoked to add the length as a semi-constrained whole number to the field-list, followed by the bitstring value. In the latter case the length and value shall be encoded as if the extension marker is not present.15.7 If an extension marker is not present in the constraint specification of the bitstring type, then 15.8 to 15.11 apply.15.8 If the bitstring is constrained to be of zero length ("ub" equals zero), then it shall not be encoded (no additions to the field-list), completing the procedures of this clause.15.9 If all values of the bitstring are constrained to be of the same length ("ub" equals "lb") and that length is less than or equal to sixteen bits, then the bitstring shall be placed in a bit-field of the constrained length "ub" which shall beappended to the field-list with no length determinant, completing the procedures of this clause.15.10 If all values of the bitstring are constrained to be of the same length ("ub" equals "lb") and that length is greater than sixteen bits but less than 64K bits, then the bitstring shall be placed in a bit-field (octet-aligned in the ALIGNED variant) of length "ub" (which is not necessarily a multiple of eight bits) and shall be appended to the field-list with no length determinant, completing the procedures of this clause.15.11 If 15.8-15.10 do not apply, the bitstring shall be placed in a bit-field (octet-aligned in the ALIGNED variant) of length "n" bits and the procedures of 10.9 shall be invoked to add this bit-field (octet-aligned in the ALIGNED variant) of "n" bits to the field-list, preceded by a length determinant equal to "n" bits as a constrained whole number if "ub" is set and is less than 64K or as a semi-constrained whole number if "ub" is unset. "lb" is as determined above.NOTE – Fragmentation applies for unconstrained or large "ub" after 16K, 32K, 48K or 64K bits.16 Encoding the octetstring typeNOTE – Octet strings of fixed length less than or equal to two octets are not octet-aligned. All other octet strings are octet-aligned in the ALIGNED variant. Fixedlength octet strings encode with no length octets if they are shorter than 64K. For unconstrained octet strings the length is explicitly encoded (with fragmentation if necessary).16.1 PER-visible constraints can only constrain the length of the octetstring.16.2 Let the maximum number of octets in the octetstring (as determined by PER-visible constraints on the length)be "ub" and the minimum number of octets be "lb". If there is no finite maximum we say that "ub" is unset. If there is no constraint on the minimum then "lb" has the value zero. Let the length of the actual octetstring value to be encoded be "n" octets.16.3 If there is a PER-visible size constraint and an extension marker is present in it, a single bit shall be added to the field-list in a bit-field of length one. The bit shall be set to 1 if the length of this encoding is not within the range of the extension root, and zero otherwise. In the former case 16.8 shall be invoked to add the length as a semi-constrained whole number to the field-list, followed by the octetstring value. In the latter case the length and value shall be encoded as if the extension marker is not present.16.4 If an extension marker is not present in the constraint specification of the octetstring type, then 16.5 to 16.8 apply.16.5 If the octetstring is constrained to be of zero length ("ub" equals zero), then it shall not be encoded (no additions to the field-list), completing the procedures of this clause.16.6 If all values of the octetstring are constrained to be of the same length ("ub" equals "lb") and that length is less than or equal to two octets, the octetstring shall be placed in a bit-field with a number of bits equal to the constrained length "ub" multiplied by eight which shall be appended to the field-list with no length determinant, completing the procedures of this clause.16.7 If all values of the octetstring are constrained to be of the same length ("ub" equals "lb") and that length is greater than two octets but less than 64K, then the octetstring shall be placed in a bit-field (octet-aligned in theALIGNED variant) with the constrained length "ub" octets which shall be appended to the field-list with no length determinant, completing the procedures of this clause.16.8 If 16.5 to 16.7 do not apply, the octetstring shall be placed in a bit-field (octet-aligned in the ALIGNED variant) of length "n" octets and the procedures of10.9 shall be invoked to add this bit-field (octet-aligned in the ALIGNED variant) of "n" octets to the field-list, preceded by a length determinant equal to "n" octets as a constrained whole number if "ub" is set, and as a semi-constrained whole number if "ub" is unset. "lb" is as determined above.NOTE – The fragmentation procedures may apply after 16K, 32K, 48K, or 64K octets.17 Encoding the null typeNOTE – (Tutorial) The null type is essentially a place holder, with practical meaning only in the case of a choice or an optional set or sequence component. Identification of the null in a choice, or its presence as an optional element, is performed in theseencoding rules without the need to have octets representing the null. Null values therefore never contribute to the octets of an encoding. There shall be no addition to the field-list for a null value.18 Encoding the sequence typeNOTE – (Tutorial) A sequence type begins with a preamble which is a bit-map. If the sequence type has no extension marker, then the bit-map merely records the presence or absence of default and optional components in the type, encoded as a fixed length bit-field. If the sequence type does have an extension marker, then thebit-map is preceded by a single bit that says whether values of extension additions are actually present in the encoding. The preamble is encoded without any length determinant provided it is less than 64K bits long, otherwise a length determinant is encoded to obtain fragmentation. The preamble is followed by the fields that encode each of the components, taken in turn. If there are extension additions, then immediately before the first one is encoded there is the encoding (as a normally small length) of a count of the number of extension additions in the type being encoded, followed by a bit-map equal in length to this count which records the presence or absence of values of each extension addition. This is followed by the encodings of the extension additions as if each one was the value of an open type field.18.1 If the sequence type has an extension marker, then a single bit shall first be added to the field-list in a bit-field of length one. The bit shall be one if values of extension additions are present in this encoding, and zero otherwise. (This bit is called the "extension bit" in the following text.) If there is no extension marker, there shall be no extension bit added.18.2 If the sequence type has "n" components in the extension root that are marked OPTIONAL or DEFAULT, then a single bit-field with "n" bits shall be produced for addition to the field-list. The bits of the bit-field shall, taken in order, encode the presence or absence of an encoding of each optional or default component in the sequence type. A bit value of 1 shall encode the presence of the encoding of the component, and a bit value of 0 shall encode the absence of the encoding of the component. The leading bit in the preamble shall encode the presence or absence of the first optional or default component, and the trailing bit shall encode the presence or absence of the last optional or default component.18.3 If "n" is less than 64K, the bit-field shall be appended to the field-list. If "n" is greater than or equal to 64K, then the procedures of 10.9 shall be invoked to add this bit-field of "n" bits to the field-list, preceded by a length determinant equal to "n" bits as a constrained whole number with "ub" and "lb" both set to "n".NOTE – In this case, "ub" and "lb" will be ignored by the length procedures. These procedures are invoked here in order toprovide fragmentation of a large preamble. The situation is expected to arise only rarely.18.4 The preamble shall be followed by the field-lists of each of the components of the sequence value which are present, taken in turn.18.5 For CANONICAL-PER, encodings of components marked DEFAULT shall always be absent if the value to be encoded is the default value. For BASIC-PER, encodings of components marked DEFAULT shall always be absent if the value to be encoded is the default value of a simple type (see 3.6.25), otherwise it is a sender's option whether or not to encode it.18.6 This completes the encoding if the extension bit is absent or is zero. If the extension bit is present and set to one, then the following procedures apply.18.7 Let the number of extension additions in the type being encoded be "n", then a bit-field with "n" bits shall be produced for addition to the field-list. The bits of the bit-field shall, taken in order, encode the presence or absence of an encoding of each extension addition in the type being encoded. A bit value of 1 shall encode the presence of the encoding of the extension addition, and a bit value of 0 shall encode the absence of the encoding of the extension addition. The leading bit in the bit-fieldshall encode the presence or absence of the first extension addition, and the trailing bit shall encode the presence or absence of the last extension addition.NOTE – If conformance is claimed to a particular version of a specification, then the value "n" is always equal to the number of extension additions in that version.18.8 The procedures of 10.9 shall be invoked to add this bit-field of "n" bits to the field-list, preceded by a length determinant equal to "n" as a normally small length.NOTE – "n" cannot be zero, as this procedure is only invoked if there is at least one extension addition being encoded.18.9 This shall be followed by field-lists containing the encodings of each extension addition that is present, taken in turn. Each extension addition that is a "ComponentType" (i.e., not an "ExtensionAdditionGroup") shall be encoded as if it were the value of an open type field as specified in 10.2.1. Each extension addition that is an "ExtensionAdditionGroup" shallbe encoded as a sequence type as specified in 18.2 to 18.6, which is then encoded as if it were the value of an open type field as specified in 10.2.1. If all components values of the "ExtensionAdditionGroup" are missing then, the "ExtensionAdditionGroup" shall be encoded as a missing extension addition (i.e., the corresponding bit in the bit-fielddescribed in 18.7 shall be set to 0).NOTE 1 – If an "ExtensionAdditionGroup" contains components marked OPTIONAL or DEFAULT, then the "ExtensionAdditionGroup" is prefixed with abit-map that indicates the presence/absence of values for each component marked OPTIONAL or DEFAULT.NOTE 2 – "RootComponentTypeList" components that are defined after the extension marker pair are encoded as if they were defined immediately before the extension marker pair.19 Encoding the sequence-of type19.1 PER-visible constraints can constrain the number of components of the sequence-of type.19.2 Let the maximum number of components in the sequence-of (as determined by PER-visible constraints) be "ub" components and the minimum number of components be "lb". If there is no finite maximum or "ub" is greater than or equal to 64K we say that "ub" is unset. If there is no constraint on the minimum, then "lb" hasthe value zero. Let the number of components in the actual sequence-of value to be encoded be "n" components.19.3 The encoding of each component of the sequence-of will generate a number of fields to be appended to the field-list for the sequence-of type.19.4 If there is a PER-visible constraint and an extension marker is present in it,a single bit shall be added to the field-list in a bit-field of length one. The bit shall be set to 1 if the number of components in this encoding is not within the range of the extension root, and zero otherwise. In the former case 10.9 shall be invoked to add the length determinant as a semi-constrained whole number to the field-list, followed by the component values. In the latter case the length and value shall be encoded as if the extension marker is not present.19.5 If the number of components is fixed ("ub" equals "lb") and "ub" is less than 64K, then there shall be no length determinant for the sequence-of, and the fields of each component shall be appended in turn to the field-list of the sequence-of.19.6 Otherwise, the procedures of 10.9 shall be invoked to add the list of fields generated by the "n" components to the field-list, preceded by a length determinant equal to "n" components as a constrained whole number if "ub" is set, and as asemi-constrained whole number if "ub" is unset. "lb" is as determined above.NOTE 1 – The fragmentation procedures may apply after 16K, 32K, 48K, or64K components.NOTE 2 – The break-points for fragmentation are between fields. The number of bits prior to a break-point are not necessarily amultiple of eight.20 Encoding the set typeThe set type shall have the elements in its "RootComponentTypeList" sorted into the canonical order specified in ITU-T Rec. X.680 | ISO/IEC 8824-1, 8.6, and additionally for the purposes of determining the order in which components are encoded when one or more component is an untagged choice type, each untagged choice type is ordered as though it has a tag equal to that of the smallest tag in the "RootAlternativeTypeList" of that choice type or any untagged choice types nested within. The set elements that occur in the "RootComponentTypeList" shall then be encoded as if it had been declared a sequence type. The set elements that occur in the "ExtensionAdditionList" shall be encoded as though they were components of asequence type as specified in 18.9 (i.e., they are encoded in the order in which they are defined).21 Encoding the set-of type21.1 For CANONICAL-PER the encoding of the component values of the set-of type shall appear in ascending order, the component encodings being compared as bit strings padded at their trailing ends with as many as seven 0 bits to an octet boundary, and with 0-octets added to the shorter one if necessary to make the length equal to that of the longer one.NOTE – Any pad bits or pad octets added for the sort do not appear in the actual encoding.21.2 For BASIC-PER the set-of shall be encoded as if it had been declared a sequence-of type.22 Encoding the choice typeNOTE – (Tutorial) A choice type is encoded by encoding an index specifying the chosen alternative. This is encoded as for a constrained integer (unless the extension marker is present in the choice type, in which case it is a normally small non-negative whole number) and would therefore typically occupy a fixed length bit-field of the minimum number of bits needed to encode the index. (Although it could in principle be arbitrarily large.) This is followed by the encoding of the chosen alternative, with alternatives that are extension additions encoded as if they were the value of an open type field. Where the choice has only one alternative, there is no encoding for the index.22.1 Encoding of choice types are not affected by PER-visible constraints.22.2 Each component of a choice has an index associated with it which has the value zero for the first alternative in the root of the choice (taking the alternatives in the canonical order specified in ITU-T Rec. X.680 | ISO/IEC 8824-1, 8.6), one for the second, and so on up to the last component in the extension root of the choice. An index value is similarly assigned to each "NamedType" within the "Extension AdditionAlternativesList", starting with 0 just as with the components of the extension root. Let "n" be the value of the largest index in the root.NOTE – ITU-T Rec. X.680 | ISO/IEC 8824-1, 28.4, requires that each successive extension addition shall have a greater tag value than the last added to the "ExtensionAddition Alterna tivesList".22.3 For the purposes of canonical ordering of choice alternatives that contain an untagged choice, each untagged choice type shall be ordered as though it has a tag equal to that of the smallest tag in the extension root of either that choice type or any untagged choice types nested within.22.4 If the choice has only one alternative in the extension root, there shall be no encoding for the index if that alternative is chosen.22.5 If the choice type has an extension marker, then a single bit shall first be added to the field-list in a bit-field of length one. The bit shall be 1 if a value of an extension addition is present in the encoding, and zero otherwise. (This bit is called the "extension bit" in the following text.) If there is no extension marker, there shall be no extension bit added.22.6 If the extension bit is absent, then the choice index of the chosen alternative shall be encoded into a field according to the procedures of clause 12 as if it were a value of an integer type (with no extension marker in its subtype constraint) constrained to the range 0 to "n", and that field shall be appended to the field-list. This shall then be followed by the fields of the chosen alternative, completing the procedures of this clause.22.7 If the extension bit is present and the chosen alternative lies within the extension root, the choice index of the chosen alternative shall be encoded as if the extension marker is absent, according to the procedure of clause 12, completing the procedures of this clause.22.8 If the extension bit is present and the chosen alternative does not lie within the extension root, the choice index of the chosen alternative shall be encoded as a normally small non-negative whole number with "lb" set to 0 and that field shall be appended to the field-list. This shall then be followed by a field-list containing the encoding of the chosen alternative encoded as if it were the value of an open type field as specified in 10.2, completing the procedures of this clause.NOTE – Version brackets in the definition of choice extension additions have no effect on how "ExtensionAdditionAlternatives" are encoded.一：英文文献名称ITU-T Recommendation X.690 (2002) | ISO/IEC 8825-1:2002, Information technology –ASN.1 encoding rules:Specification of Packed Encoding Rules (PER)。

ITUT与IEEE协议规范

ITUT与IEEE协议规范ITU-T的中文名称是国际电信联盟远程通信标准化组(ITU-T for ITU Telecommunication Standardization Sector), 它是国际电信联盟管理下的专门制定远程通信有关国际标准的组织。

该机构创建于1993年，前身是国际电报电话咨询委员会(CCITT 是法语ComitéConsultatif International Téléphonique et Télégraphique的缩写, 英文是International Telegraph and Telephone Consultative Committee)，总部设在瑞士日内瓦。

ITU-T的各类建议的分类由一个首字母来代表，称之系列(见下文)，每个系列的建议除了分类字母以外还有一个编号，比如说"V.90"。

参见Category:ITU-T建议.重要的ITU-T的系列与建议有：A - ITU-T 各部分工作的组织协调B - 语法规定 : 定义, 符号, 分类C - 常规通信统计D - 常规关税原则E - 总体网络操作，电话服务，服务操作与人的要素E.123 国家与国际电话号码规范E.163 国际电话服务号码分配计划E.164 国际公共远程通信号码分配计划补充 2 - 号码可移动性F - 非电话远程通信服务G - 传输系统与媒体，数字系统与网络G.711 音频压缩 (mu-law)G.722 音频压缩 (宽带)G.722.1 音频压缩 (宽带, 低码率)G.722.2 语音压缩 AMR-WB (宽带, 低码率)G.723.1 语音压缩 CELPG.726 音频压缩 ADPCMG.728 语音压缩 LD-CELPG.729 语音压缩 ACELPH - 视频音频与多媒体系统复合方法H.223 低码率多媒体通信复合协议H.225.0 也被称之实时传输协议H.261 视频压缩标准, 约1991年H.262 视频压缩标准(与MPEG-2第二部分内容相同), 约1994年H.263 视频压缩标准, 约1995年H.263v2 (也就是 H.263+) 视频压缩标准, 约1998年H.264 视频压缩标准(与MPEG-4第十部分内容相同), 约2003年H.323 基于包传输的多媒体通信系统附录 D - 基于H.323系统的实时传真附录 G - 文本传输与文本集(Text conversation and Text SET)附录 J - H.323 附录 F 的安全性附录 M.1 - H.323中的信令协议隧道 (Qsig)附录 M.2 - H.323中的信令协议隧道 (Qsig)H.324 低码率下的多媒体通信终端H.332 基于H.323拓展的宽松双向视频会议在高清编码/解码技术产生之前，视频会议数据是基于通用交换格式 (CIF) 进行编码的。

G652、G657光纤介绍

1、G.657光纤抗弯曲特性分析与其他单模光纤相比,G.657光纤最显著的特点是弯曲不敏感。这就意味着G.657光纤的弯曲损耗比较小。 G.657光纤具有良好的抗弯曲性能，使其适用于光纤接入网，包括位于光纤接入网终端的建筑物内的各种布线。（1）光纤分类按照是否与G.652光纤兼容的原则，将G.657光纤划分成了A大类和B大类光纤，同时按照最小可弯曲半径的原则，将弯曲等级分为1，2，3三个等级，其中1对应10mm最小弯曲半径，2对应7.5mm最小弯曲半径，3对应5mm最小弯曲半径。结合这两个原则，将G.657光纤分为了四个子类，G.657.A1、G.657.A2、 G.657.B2和G.657.B3光纤，具体分类如下表所示：
附加衰减：光纤成缆之后产生的衰减。
1.附加衰减：在实际使用的光缆线路中,光缆中的光纤不可避免地受到各种弯曲应力作用。这些弯曲应力作用的结果是使光纤中的传导模变换为辐射模而导致光功率损失。这些弯曲应力作用的结果是使光纤中的传导模变换为辐射模而导致光功率损失。光纤的弯曲损耗α与光纤的折射率分布结构参数(相对折射率△、纤芯半径a)有关,即 α=k(a/△)2 式中,k是比例常数,它与光纤接触面的粗糙程度和材料特性有关。结论：抗弯曲光纤应该具有比较大的芯/包折射率差的结构.
这种光纤可支持用于在155m波段的25gbs的干线系统但由于在该波段的色散较大若传输10gbs的信号传输距离超过50公里时就要求使用价格昂贵的色散补偿模11g652g652光纖oh吸收峰2g652光纤的分类g652光纤是现在网络上应用比较多的一种光纤itut对于g652分为四类光g652四种光纤的分类主要基于pmd偏振模色散的要求和在1383nm处的衰耗要求
另外,阶跃折射率单模光纤的弯曲性能也可以用一个著名的元量纲参数MAC, 即模场直径(MFD)与截止波长λc之间的函数关系来表示

ITUT光传送网OTN标准进展.ppt

电信科学技术第五研究所
ITU-T光传送网OTN标准进展
朱洪
电信科学技术第五研究所 2011 10.18
1
电信科学技术第五研究所
SG15传送网标准成就
自2000年以来，ITU-T SG15研究组在有线通信技术领域多个方面取得标准化进展，包括：
➢传送网技术（ASON，EoT，MPLS-TP，OTN） ➢光传输技术（DWDM，40G系统，城域网，海底传输系统） ➢传输设备及网络保护/倒换 ➢光纤光缆 ➢光接入网技术（xDSL，GPON，XGPON，HN） ➢频率/时间同步、传递及分配 ➢传送网管理、控制及OAM
4
内容
➢ 业务需求 ➢ OTN体系架构 ➢ OTN接口 ➢ OTN复用及映射 ➢ OTN比特率及帧结构 ➢ OTN指标 ➢ OTN应用
电信科学技术第五研究所
5
OTN业务需求
电信科学技术第五研究所
业务
映射
OTN体系
STM-1/STM-4
GMP
FC-100 GE
GMP TTT+GMP/GFP-F
OPU0
OTN指的是 ➢用更好的性能传送所有数字净荷，支持下一代动态业务，具有更高的、现有的光波分复用WDM传送解决方案所不能比拟的运营效率 ➢支持广泛的窄带和宽带业务： SDH/SONET IP-based services Ethernet services ATM services Frame relay services Audio/video services
BMP
OPUflex
CPRI-4/5/6
BMP
Overview ing types
AMP：Asynchronous Mapping Procedure BMP：Bit-synchronous Mapping Procedure

易可导航-企业宣传商业计划产品介绍类PPT模板-时尚风格系列-2024 (20)-good

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Subtitle 1

UT525 UT526 说明书

I. OverviewUT525/UT526 is a multifunction digital instrument adopting brand-new design using large-scale integrated analogue and digital circuits and micro-processor chip. It mainly measures RCD parameters, low-resistance continuity, insulation resistance,DC&AC Voltage, etc. The versatile functionality, high accuracy and ease of use features make it widely used to measure insulation and continuity of various kinds of electrical equipments, and an ideal tool for maintenance, inspection and tests badly needed for RCD in those equipments.II. Safety InformationThis instrument was designed, manufactured and tested according toIEC61010 safety standard (Safety Requirements for Electrical Equipment). The manual includes safety information related to the safe operation of the instr -ument. Please read the following instructions before use and strictly follow them during the operation.W arning● Please read and understood the manual before using the instrument.● Use the instrument as specified in the manual and keep the manual well for future reference.● Misuse may cause personal injury or damage to the instrument during tests.Sign on the instrument indicates users to refer to the manual for details in order to ensure safe operation of the instrument.DangerWarning. CautionIII. Electrical SymbolsIV. SpeciﬁcationsAccuracy: ±(a% of reading+ b digits), calibration per year Ambient Temperature & Humidity: 23±5℃, 45~75%RH.RCD TestTest current 10mA 30mA 100mA 300mAApplied voltageVoltage: 220V±10%, frequency: 45Hz-65Hz Test current accuracy At 220Vac ± 2: 0 +10%Trip timeAccuracy ±(5%+2)(10mA) range: 0-2,000mS (30mA) range: 0-500mS(100mA) range: 0-300mS(300mA) range: 0-300mS Insulation Resistance(UT525)Rated voltage 100V 250V 500V Test range 0.05MΩ-200MΩOpen circuit voltage DC 100V±10% DC 250V±10% DC 500V±10% Rated test current 100KΩ load 250KΩ load 500KΩ loadShort-circuit current ＜1.8mAAccuracy 0.05MΩ-200MΩ: ±(5%+5)0.9mA-1.1mA 0.9mA-1.1mA 0.9mA-1.1mA Rated voltage 250V 500V 1,000V Test range 0.05MΩ-200MΩ 0.05MΩ-300MΩ 0.05MΩ-500MΩ Open circuit voltage DC 250V±10% DC 500V±10% DC 1,000V±10% Rated test current 500KΩ load 1MΩ load 250KΩ loadShort-circuit current ＜1.8mAAccuracy 0.05MΩ-500MΩ: ±(5%+5)0.9mA-1.1mA 0.9mA-1.1mA 0.9mA-1.1mA Voltage DCV ACVTest range ±0-±440V 0-440V (50/60Hz), for ＜10V, it is for reference only. Resolution 1VAccuracy±(2%+3)FrequencyTest range 20Hz-100Hz Resolution 1HzAccuracy Just for reference● Display: LCD display, max reading: 9999● Low battery indication: ● Over limit indication: “OL ”● Auto range function ● Unit display: Display function and unit symbols simultaneously.● Work conditions: 0℃-40℃/ ≤85%RH ● Storage condition: -20℃-60℃/≤90%RH ● Dimensions: 150mm(L)×100mm(W)×71mm(D)● Current consumption: about 50mA (1,000V output) (about 10mA in general condition)● Accessories: test lead, alkaline battery (1.5V, AA)×6, manual, carrying bag ● Weight: 0.7kg (including batteries)● Power: alkaline battery (1.5V, AA)×6V . Tester Description (Front View, See Figure 1)1. L : Live terminal for RCD measurement and positive terminal for voltage measurement2. E : earth terminal for RCD measurement3.N : Neutral terminal for RCD measurement and input negative terminal for voltage tmeasurement4. LINE : High voltage output terminal for insulation resistance measurement5. LCD6. RCD current setup/voltage switchover button7. RCD phase angle switchover/zeroing button8. Test button Figure 1VI . Buttons and Rotary Switch Functions1. I/VOLT: Select RCD test currents/switch between AC and DC voltage;2. ANG/ZERO: Switch phase angle for RCD measurements/ reset to zero before continuity test;3. TEST: Begin a test;4. Set rotary switch to Continuity: Test for grounding continuity;5. Set rotary switch to RCD/V: Measure RCD/AC&DC voltage;6. Set rotary switch to 100V/250V/500V (UT525) or 250V/500V/1000V (UT526): select a output voltage under insulation resistance measurement.VII. Preparations before MeasurementWhen the instrument turns on, if low battery indicator shows on left side of LCD,it indicates the battery is running out and please replace the battery timely.VIII. Testing for Continuity(See Figure 2)Multifunction Electric Testers● Do not measure any circuit with voltage above 440Vac or 440Vdc.● Do not take measurements on sites exposed to flammables, for spark may cause the explosion.● Do not use the Tester if it is wet or the operator’s hands are wet.● Do not touch conductive parts of test leads during measurement.● Do not use the instrument if it works abnormally. Eg: the instrument is damaged or the metal is exposed.● Please take caution when working voltage exceeds 33Vrms, 46.7Vacrms or 70Vdc, for it may cause electric shock.● The electric storage in tested circuits must be released after finishing high resistance measurements.● Do not replace the battery if the instrument is under wet conditions.● Please ensure the test leads are firmly secured to input terminals of the instrument.● Ensure the instrument is turned off before opening the battery cover.● The tested circuit should be discharged completely and totally separated from the power before making resistance measurements.● If it is necessary to replace the test leads or power adaptor, please use only ● If low battery indicator( ) shows, stop using the instrument. Take ● Do not store or use the instrument in the places exposed to high temperature, high humidity, explosives, flammables or strong electromagnetic field.● Clean the instrument casing with dampened cloth and mild detergent. No abrasives or solvents are allowed.● When the instrument is wet, dry it first before storing it.Insulation Resistance(UT526)● Auto voltage release ● Red warning light ● Compliances: CATIII 600V, Pollution Degree II as per IEC61010● Do not measure with the battery cover opened.● Do not touch any circuit under test when you are measuring insulation or RCD.9. Rotary switchTo test continuity:1. Connect the tested object and the Tester as shown in Figure 2;2. Set the rotary switch to Continuity;3. Press TEST button to begin the test;Caution:● To ensure the test accuracy, please short-circuit the test leads and zero the display(Zeroing Steps: set the tester under continuity status, short-circuit the test leads, press TEST button and then press ANG/ZERO button to reset the resistance of test leads to “0”, ZERO shows on LCD.)● Do not test any live objects.Figure 2IX. Measuring RCD(See Figure 3)Caution:Caution:Figure 3XMeasuring Voltage (See Figure 4)Figure 4XI. Measuring Insulation Resistance (See Figure 5)CautionFigure 5XII. Replacing the Battery(See Figure 6)Caution● Do not use old and new batteries at the same time.● Pay attention to the polarity during replacing battery.Danger1. To avoid potential electric shock, remove the test leads away from the instrument before replacing battery.2. Do not measure with the battery opened.3. When sign “ ” is displayed on LCD, it means the battery needs to be replaced.Figure 6XIII. MaintenanceCleaning the Housing:●Wipe the surface with soft wet cloth or sponge.● To avoid instrument damage, do not dip the instrument into water.● When the instrument is wet, make it dry and then store.● When the instrument needs to be checked or repaired, please have it serviced by qualified professional personnel or designated service center.The content is subject to change without prior notice.**END**To measure RCD,1. Set the rotary switch to RCD/V;2. Press I/VOLT button to set up test current (available: 10mA/30mA/100mA/ 300mA);3. Insert supplied test leads (with power plug) to the Tester (Red-L; Green-E; Blue-N) and plug the plug into 220V civil socket;4. Press TEST button to start.● Ensure the power socket is reliably grounded when measuring RCD.● Ensure the power socket Live, Neutral and Earth lines are properly connected when measuring RCD.● Please take caution when taking RCD measurements, for they are all done under high voltage status.To measure voltage:1. Set the rotary switch to RCD/V;2. Long press I/VOLT to switch between AC and DC mode;3. a. Insert test leads into input terminals (Red to L, Black to N) and connect Red & Black clips or probes to tested circuit.b. Or Insert the special test leads (with plug) to the input terminals (Red to L, Green to E, Blue-N) and plug the plug into the tested socket.4. Press TEST button, the Tester will automatically detect out AC/DC mode and display the voltage and frequency readings on LCD.● Do not input any voltage higher than 440V or 440Vrms, although it may be possible to display a higher voltage, it may damage the instrument.● To avoid electric shock, please take caution when measuring high voltage.● After completing the measurements, remove test leads away from tested circuits and disconnect them from the input terminals of the instrument.● Do not measure with the battery cover opened.● Make sure the tested circuit is dis-energized, completely discharged and totally separated from the power supply before measurement. Do not measure the insulation resistance of live equipments or lines.● Do not measure with the battery cover opened.● Do not short-circuit the test leads under high-voltage output status or prepare to measure insulation resistance after the high voltage has already been output.● After the measurement finishes, do not touch the tested circuit, for the storedcapacitance in the circuit may cause electric shock.● Do not touch the test leads even after they are removed away from the circuit, wait until the test voltage is totally released.To measure insulation resistance:1. Turn the rotary switch to one of 100V/250V/500V (UT525) or 250V/500V/ 1000V (UT526) test voltage.2. Insert test leads into input terminals (Red to LINE, Black to N) and connect them to the tested circuit. High voltage is output from LINE terminal.3. Continuous Measurement: Press TEST button, the Tester will self-lock, output the test voltage and emit warning light simultaneously. With the measurement finished, press TEST to unlock and stop the continuous measurement.To replace the battery, follow the steps as below:1. Turn off the instrument (turn the rotary switch to off), and remove away the test leads.2. Unscrew the battery cover, take out the old batteries and replace with new 6 pcs batteries.3. Screw up the battery cover again.P/N:110401104486X DATE:2018.06.26 REV.5。

ITUT与IEEE协议规范

ITU-T与IEEE协议规范ITU-T的中文名称是国际电信联盟远程通信标准化组(ITU-TforITUTelecommunicationStandardizationSector),它是国际电信联盟管理下的专门制定远程通信相关国际标准的组织。

该机构创建于1993年，前身是国际电报电话咨询委员会(CCITT是法语ComitéConsultatifInternationalTéléphoniqueetTélégraphique的缩写,英文是InternationalTelegraphandTelephoneConsultativeCommittee)，总部设在瑞士日内瓦。

ITU-T的各种建议的分类由一个首字母来代表，称为系列(见下文)，每个系列的建议除了分类字母以外还有一个编号，比如说"V.90"。

参见Category:ITU-T建议.重要的ITU-T的系列和建议有：A-ITU-T各部分工作的组织协调B-语法规定:定义,符号,分类C-常规通信统计D-常规关税原则E-总体网络操作，电话服务，服务操作和人的要素E.123国家和国际电话号码规范E.163国际电话服务号码分配计划E.164国际公共远程通信号码分配计划补充2-号码可移动性F-非电话远程通信服务G-传输系统和媒体，数字系统和网络G.711音频压缩(mu-law)G.722音频压缩(宽带)G.722.1音频压缩(宽带,低码率)G.722.2语音压缩AMR-WB(宽带,低码率)G.723.1语音压缩CELPG.726音频压缩ADPCMG.728语音压缩LD-CELPG.729语音压缩ACELPH-视频音频以及多媒体系统复合方法H.223低码率多媒体通信复合协议H.225.0也被称为实时传输协议H.261视频压缩标准,约1991年H.262视频压缩标准(和MPEG-2第二部分内容相同),约1994年H.263视频压缩标准,约1995年H.263v2(也就是H.263+)视频压缩标准,约1998年H.264视频压缩标准(和MPEG-4第十部分内容相同),约2003年H.323基于包传输的多媒体通信系统附录D-基于H.323系统的实时传真附录G-文本传输和文本集(TextconversationandTextSET)附录J-H.323附录F的安全性附录K-基于HTTP协议服务的H.323传输控制信道附录M.1-H.323中的信令协议隧道(Qsig)附录M.2-H.323中的信令协议隧道(Qsig)H.324低码率下的多媒体通信终端H.332基于H.323拓展的宽松双向视频会议在高清编码/解码技术产生之前，视频会议数据是基于通用交换格式(CIF)进行编码的。

国际管理类的UT24种期刊与FT45种期刊

UT/DALLAS界定的24种期刊Number Journals ABS SCI SSCI1 Academy of Management Journal Grade Four * Y2 Academy of Management Review Grade Four * Y3 Administrative Science Quarterly Grade Four * YDecision AnalysisInterfaces4 Information Systems Research Grade Four * YINFORMS Journal on ComputingINFORMS Transactions on Education5 Journal of Accounting and Economics Grade Four * Y6 Journal of Accounting Research Grade Four * Y7 Journal of Consumer Research Grade Four * Y8 Journal of Finance Grade Four * Y9 Journal of Financial Economics Grade Four Y10 Journal of International Business Studies Grade Four Y11 Journal of Marketing Grade Four * Y12 Journal of Marketing Research Grade Four * Y13 Journal of Operations Management Grade Four 一区Y14 Journal on Computing Grade Three 三区15 Management Science Grade Four * Y16 Manufacturing and Service Operations Management Grade Three Y17 Marketing Science Grade Four * Y18 MIS Quarterly Grade Four * Y19 Operations Research Grade Four * 二区Y20 Organization Science Grade Four * Y21 Production and Operations Management Grade Three 一区Service Science22 Strategic Management Journal Grade Four * Y23 The Accounting Review Grade Four * Y24 The Review of Financial Studies Grade Four * YTransportation Science附录2：金融时报45种期刊Number Journals ABS SCI SSCI1 Entrepreneurship Theory and Practice (Baylor University,Waco, Texas)Grade FourY2 Harvard Business Review (Harvard Business SchoolPublishing)Grade FourY3 Human Resource Management (John Wiley and Sons) Grade Four Y4 Journal of Applied Psychology (American PsychologicalAssociation) Grade Four Y5 Journal of Business Venturing (Elsevier) Grade Four Y6 Journal of Consumer Psychology (Elsevier) Grade Four Y7 Journal of Financial and Quantitative Analysis Grade Four Y8 Journal of Financial Economics (Elsevier) Grade Four Y9 Journal of International Business Studies (Academy ofInternational Business)Grade FourY10 Journal of Management Studies (Wiley) Grade Four Y11 Journal of Operations Management (Elsevier) Grade Four 一区Y12 Organization Studies (SA GE) Grade Four Y13 Organizational Behaviour and Human Decision Processes(Academic Press) Grade Four Y14 Quarterly Journal of Economics (MIT) Grade Four Y15 Review of Accounting Studies (Springer) Grade Four Y16 Academy of Management Journal (Academy ofManagement, Ada, Ohio) Grade Four *Y17 Academy of Management Review (Academy ofManagement) Grade Four *Y18 Accounting, Organisations and Society (Elsevier) Grade Four *Y19 Accounting Review (A merican Accounting Association) Grade Four *Y20 Administrative Science Quarterly (Cornell University) Grade Four * Y21 American Economic Review (A merican EconomicAssociation, Nashville) Grade Four *Y22 Econometrica (Econometric Society, University ofChicago) Grade Four *一区Y23 Information Systems Research (Informs) Grade Four *Y24 Journal of Accounting and Economics (Elsevier) Grade Four *Y25 Journal of Accounting Research (University of Chicago) Grade Four *Y26 Journal of Consumer Research (University of Chicago) Grade Four *Y27 Journal of Finance (Blackwell) Grade Four *Y28 Journal of Marketing (A merican Marketing Association) Grade Four *Y29 Journal of Marketing Research (A merican MarketingAssociation) Grade Four *Y30 Journal of Political Economy (University of Chicago) Grade Four *Y31 Management Science (Informs) Grade Four *Y32 Marketing Science (Informs) Grade Four *Y33 MIS Quarterly (Management Information SystemsResearch Centre, Unviersity of Minnesota)Grade Four *Y34 Operations Research (Informs) Grade Four *二区Y35 Organization Science (Informs) Grade Four *Y36 Review of Financial Studies (Oxford University Press) Grade Four *Y37 Strategic Management Journal (John Wiley and Sons) Grade Four *Y38 Academy of Management Perspectives (AMP) Grade Three Y39 California Management Review (UC Berkely) Grade Three Y40 Contemporary Accounting Research (Wiley) Grade Three Y41 Journal of Business Ethics (Kluwer Academic) Grade Three Y42 Rand Journal of Economics (The Rand Corporation) Grade Three Y43 Sloan Management Review (MIT) Grade Three Y44 Journal of the A merican Statistical Association(American Statistical Association) Grade Four 一区45 Production and Operations Management (POMS) Grade Three 一区。

国际电联操作公报-ITU

目录页码一般信息国际电联《操作公报》后附的清单：电信标准化局的说明 (3)批准ITU-T建议书 (4)信令区域/网络代码（SANC）的指配（ITU-T Q.708建议书（03/99））巴西（联邦共和国） (4)电话业务：丹麦（丹麦能源署，哥本哈根） (5)业务限制 (6)回叫和迂回呼叫程序（2006年全权代表大会修订的第21号决议） (6)对业务出版物的修正船舶电台和水上移动业务识别码分配表（名录V） (7)用于公共网络和订户的国际识别规划的移动网络代码（MNC） (8)信令区域/网络代码（SANC）列表 (8)国际信令点代码（ISPC）列表 (9)国内编号方案 (11)www.itu.int2 国际电联《操作公报》一般信息国际电联《操作公报》后附的清单电信标准化局的说明A. 电信标准化局或无线电通信局公布了以下清单，作为国际电联《操作公报》（OB）的附件：《操作公报》编号1096 2016年法定时间1088 国际电信计账卡的颁发者标识号码列表（根据ITU-T E.118建议书(05/2006)）（截至2015年11月15日）1086 用于公共网络和订户的国际识别规划的移动网络代码（MNC）（根据ITU-T E.212建议书（05/2008））（截至2015年10月15日）1067 国际信令点代码（ISPC）列表（符合ITU-T Q.708建议书（03/99））（截至2015年1月1日）1066 信令区域/网络编码（SANC）列表（ITU-T Q.708建议书（03/99））的补遗（截至2014年12月15日）1060 国际电联电信运营商代码列表（根据ITU-T M.1400建议书（07/2006））（截至2014年9月15日）1055 不同国家业余台站之间无线电通信的现状（根据《无线电规则》第25.1款的可选条款）以及各主管部门指配给其业余和实验台站的呼号表（截至2014年7月1日）1015 移动网络的接入代码/号码（根据ITU-T E.164建议书（11/2010））（截至2012年11月1日）1005 国家和地理区域移动代码列表（ITU-T E.212建议书增补（05/2008））（截至2012年6月1日）1002 信息通信业务中非标准设施的国家或地理区域代码列表（ITU-T T.35建议书（02/2000）的补遗）（截至2012年4月15日）1001 被指定分配ITU-T T.35建议书终端提供商代码的各国管理机构名单（截至2012年4月1日）1000 业务限制（当前有效的电信运营相关业务限制的概括清单）（截至2012年3月15日）994 拨号程序（国际前缀、国内（中继线）前缀和国内（重要）号码）（根据ITU-T E.164建议书（11/2010））（截至2011年12月15日）991 ITU-T E.164建议书分配国家代码列表（ITU-T E.164建议书（11/2010）的补遗）（截至2011年11月1日）991 回叫和迂回呼叫程序（2006年全权代表大会第21号决议）980 电报目的地标志列表（根据ITU-T F.32建议书（10/1995））（截至2011年5月11日）978 电传目的地代码（TDC）和电传网络识别代码（TNIC）列表（ITU-T F.69建议书（06/1994）和F.68建议书（11/1988）的补遗）（截至2011年4月15日）977 数据网络识别代码（DNIC）列表（根据ITU-T X.121建议书（10/2000））（截至2011年4月1日）976 数据国家或地理区域代码列表（ITU-T X.121建议书（10/2000）的补遗）（截至2011年3月15日）974 主管部门管理域（ADMD）名称列表（根据ITU-T F.400和X.400系列建议书）（截至2011年2月15日）972 地面集群无线电移动国家代码列表（ITU-T E.218建议书（05/2004）的补遗）（截至2011年1月15日）955 国内网络中采用的各种信号音（根据ITU-T E.180建议书（03/98））（截至2010年5月1日）669 用于国际公共电报业务的五字母代码组（根据ITU-T F.1建议书（03/1998））B. 以下列表可从ITU-T网站在线获取：国际电联电信运营商代码列表（ITU-T M.1400建议书(03/2013)）www.itu.int/ITU-T/inr/icc/index.html办公传真表（ITU-T F.170建议书）www.itu.int/ITU-T/inr/bureaufax/index.html 经认可运营机构（ROA）名单www.itu.int/ITU-T/inr/roa/index.html3批准ITU-T建议书通过AAP-86通函宣布，根据ITU-T A.8建议书规定的程序批准了以下建议书：–ITU-T G.7041/Y.1303 (08/2016)：通用成帧程序–ITU-T T.832 (08/2016)：信息技术– JPEG XR图像编码系统–图像编码规范–ITU-T T.835 (08/2016)：信息技术– JPEG XR图像编码系统–参考软件信令区域/网络代码（SANC）的指配（ITU-T Q.708建议书（03/99））电信标准化局的说明应巴西主管部门的要求，电信标准化局主任根据ITU-T Q.708建议书（03/99），指配了以下信令区域/网络代码（SANC），用于该国/地理区域7号信令系统网络的国际部分：国家/地理区域或信令网络SANC巴西（联邦共和国）7-057____________SANC：信令区域/网络代码。

中国移动宽带接入技术GPON介绍(ppt 63页)

OLT测试每个ONU的平均光功率P，将结果P与阈值TL和 TH比较：
适合广播业务、不对称业务
带宽利用率高
拓扑结构适合接入网环境
－与用户与业务节点之间的分布天然吻合。
理想的光纤接入网、升级性好 ——无源纯介质的光分配网络对传输
技术体制和波长的透明性带来了升级性好的优势。
PON的发展历程
上世纪90年代初提出PON概念 1995年成立FSAN（Full Service Access Networks)
ONU 1
ONU 2
OLT
ONU 3
ONU 4
图中黑点为无源光分/合路器（光耦合器）。适合集中的用户群，比如商业大楼里的企事业用户。
Passive tree architecture (2)
ONU 1 ONU 2
OLT
可根据需要放置光分/合路器，可多级。适合相对集中的几个用户群。
ONU 3 ONU 4 ONU 5
Q3 接入网系统网管功能
UNI (PON)
T
用户侧
a
AF
S/R ONU
ONU
S/R ODN OLT
接入链路
PON的功能参考配置
SNI
V 业务节
点功能
网络侧
O FTTH N T
O
N T
copper
fibre
O FTTB/C
N U
fibre
O N T
copper
FTTCab
O
N
fibre
U
home network
◦ 2.4 Gb/s / 1.2 Gb/s
◦ 2.4 Gb/s / 2.4 Gb/s
GPON的特点
◦ 基于ATM信元和GEM帧 ◦ 可提供更大的业务容量。 ◦ QoS保证的全业务接入，很好地支持TDM业务 ◦ 强大的OAM能力 <-------- 开销复杂,成帧复杂 ◦ 技术较复杂，成本较高，技术成熟度比APON、EPON差。

通信单模光纤的相关标准介绍与分类

通信单模光纤的相关标准介绍与分类1、概述光纤是光缆的核心部分，光纤通信技术的发展大大推动了光纤的标准化工作的进程。

目前，主要从事光纤和光缆国际标准化研究的组织是IEC(国际电工技术委员会)和ITU-T(国际电信联盟)。

IEC侧重于光纤光缆生产厂商，主要关注的是产品性能规范和测试方法，而ITU-T则侧重于通信运营商和传输设备制造商，主要关注光纤在通信运营网络中的正确合理使用。

虽然IEC与ITU-T的研究的侧重点不同，但两个组织对光纤传输特性的要求是相同的，他们根据光纤的零色散波长、截止波长等是否产生位移而将单模光纤进行划分。

2、光纤的分类光纤从传输模式上可分单模光纤和多模光纤两种。

而IEC和ITU-T又根据零色散波长和截止波长是否产生位移将单模光纤划分为6种类型。

其中ITU-T标准将单模光纤分为G.652、G.653、G.654、G.655和G.656等类型，而IEC则将单模光纤分为B1.1、B1.2、B1.3、B2、B4等，两个国际标准中光纤的分类对应关系及主要特征详见下表：ITU-T与IEC光纤型式对照表ITU-T分类 IEC分类光纤名称主要特征及应用G.652AG.652B B1.1 非色散位移单模光纤零色散波长在1300～1324nm处，最佳工作波长为1310nm，也可用在1550nm波长范围，但1550nm的色散较大，适用于10GBit/s以下中距离传输。

如在1550nm波段长距离传输需要进行色散补偿。

G.654 B1.2 截止波长位移单模光纤零色散波长在1300～1324nm处，截止波长位移至1310nm以上区域，1550nm衰减最低，可达0.18dB/km，主要用于海缆。

1550nm色散大。

G.652CG.652D B1.3 波长段扩展的非色散位移单模光纤(也称全波光纤或低水峰光纤) 零色散波长在1300～1324nm处，消除了G.652A、B光纤存在的1383nm处的水峰，将工作波长扩展到1360-1530nm，用于城域网全波段CWDM传输。

美国高中生物教材科学写作的特点分析及借鉴

美国高中生物教材科学写作的特点分析及借鉴作者：方丽丽杜军来源：《教学与管理(理论版)》2020年第04期摘要美国高中生物主流教材《科学发现者·生命的动力》共涵盖了157个科学写作任务点。

文章从生物学科核心素养的视角分析了这些写作任务的特点并依据其特点给出了具体的写作任务设计案例，最后呈现并分析了部分学生作品，以期丰富生物学教学中对学生学习效果的评价方式。

关键词科学写作科学发现者生物学科核心素养学习效果评价科学写作是学习者通过解释、组织、回顾、反思或连结科学知识的书写与纪录等形式，经过整合建构的学习方式以理解和掌握科学知识的过程[1]。

它是科学教育的重要组成部分：一方面，它能促进学生对科学概念的了解，提升学生的反思能力，增进学生的科学推理能力;另一方面，科学写作作为教师与学生沟通的媒介，可以作为教师教学的依据[2]。

美国高中生物教材注重学生的发展，多方面提升学生能力，在教材中滲透了大量的科学写作任务点。

本文以《科学发现者·生命的动力》为例，从生物学科核心素养的角度对其特点进行具体分析。

生物学科核心素养注重培养学生在真实情景中解决问题的品格和能力，包括生命观念、科学思维、科学探究、社会责任。

《科学发现者·生命的动力》教材（下文称“美版教材”）中的科学写作任务设计巧妙、考察形式多样、针对性强，能够从以上这四个方面综合训练和提升学生的核心素养。

具体来说，美版教材一共涵盖了157个科学写作任务点，其中上册[3]共有61个，中册[4]44个，下册[5]52个，主要分布在章节测评、标准化测试、生物实验室、生物学前沿等内容部分（表1）。

相比较而言，我国高中的生物学教学则是以“储存知识”为基本取向，以学生“被动接受”为基本形式[6]，其考察方式也以侧重于知识点的理解和记忆的简答和填空题为主，很少有针对性题目对学生的综合能力进行评价。

因此，我们须要从美版教材的写作任务的设计特点中寻找经验，以期丰富我国生物学教学中对学生学习效果的评价方式。

美国初中科学教科书《科学探索者》“探索活动”体例特色

美国初中科学教科书《科学探索者》“探索活动”体例特色作者：李宛鸽，董玉芝来源：《教育教学论坛》 2016年第43期李宛鸽，董玉芝（延边大学理学院，吉林延吉133000）摘要：本文将美国初中科学教科书《科学探索者·天气与气候》的“探索活动”分为“实验与操作”、“技术与设计”、“技能与应用”和“图像演示”四种类型，进而分析这本教材的“探索活动”体例注重动手操作和动脑思考，重视技能的过程性培养，并且不同的探索活动具有不同的功能，彰显了《科学探索者》一书“探索”的核心理念。

关键词：美国；初中科学教科书；“探索活动”；体例特色中图分类号：G642.0 文献标志码：A 文章编号：1674-9324（2016）43-0210-02收稿日期：2016-05-28作者简介：李宛鸽（1995-），女（汉族），黑龙江牡丹江人，延边大学理学院2012级地理科学专业；董玉芝（1968-），女（汉族），吉林延吉人，延边大学师范学院学科教育教研部，副教授。

美国自创立科学课程以来，中学科学教育的理念一直随着社会的需求不断地调整、改变，已经形成了如今重视科学、技术、社会（STS）以及科学教育的大众化思想理念。

同时，美国的教科书充分体现出对建构主义学习理论的运用，注重学生探究、动手和实践能力，让学生在体验的过程中建构新知识。

《科学探索者》因其“探索科学奥秘、指导研究性学习、知识能力方法并重、动手动脑趣味无穷”的教材特点，逐渐成为美国最权威的研究性学习教材。

本文依据浙江教育出版社出版的《科学探索者·天气与气候》（中国版）中的“探索活动”，对其进行分类，讨论该版教科书中“探索活动”体例的特色。

一、美国初中科学教科书《科学探索者》的内容及“探索活动”类型美国初中科学教科书《科学探索者》由17个分册组成，本文选取《天气与气候》一册进行分析。

《科学探索者·天气与气候》共有4个章节。

第一章为大气，从身边的空气讲起，介绍了地球上大气的成分、结构，也介绍了大气的气压、气温及其随着海拔、场所和时间的变化而变化的规律和特点，共编写了4节内容。

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Part 03
Life isn't about waiting for the storm to pass. it's about learning to dance Life isn't it's about learning to dance in the rain.

OTN技术体系介绍

一.OTN技术体系介绍之阿布丰王创作1.概述从1998年ITUT正是提出OTN的概念到现在，OTN的尺度体系已经完善，技术也已经成熟。

OTN尺度体系主要由如下尺度组成：G.872：定义了光传送网的网络架构。

采取基于G.805的分层方法描述了OTN的功能结构，规范了光传送网的分层结构、特征信息、客户/服务层之间的关联、网络拓扑和分层网络功能，包含光信号传输、复用、选路、监控、性能评估和网络生存性等G.709：其地位类似于SDH体制的G.707。

定义了光网络的网络节点接口。

建议规范了光传送网的光网络节点接口，包管了光传送网的互连互通，支持分歧类型的客户信号。

建议主要定义光传送模块n(OTMn)及其结构，采取了“数字封包”技术定义各种开销功能、映射方法和客户信号复用方法。

通过定义帧结构开销，可以实施光通路层功能，例如呵护、选路、性能监测等；通过确定各种业务信号到光网络层的映射方法，实现光网络层面的互联互通，因为未来的光网络工作在多运营商环境下，其实不但仅是各业务客户信号接口的互通。

其地位类似于SDH体制的G.707。

G.798：建议采取G.806规定的传输设备的分析方法，对基于G.872规定的光传送网结构和基于G.709规定的光传送网网络节点接口的传输网络设备进行分析。

定义了OTN的原子功能模块，各个层网络的功能，包含客户/服务层的适配功能、层网络的终结功能、连接功能等。

其地位类似于SDH体制的G.783。

G.7710：通用设备管理功能需求，适用于SDH、OTN。

G.874：OTN网络管理信息模型和功能需求。

G.7710：描述OTN的五大管理功能（FCAPS：Fault故障、Configuration配置、Accounting计费、Performance性能、Security平安）。

G.808.1：通用呵护倒换线性呵护，适用于SDH、OTN。

G.808.2：通用呵护倒换环形呵护，适用于SDH、OTN。