對于ip地址范圍以及子網劃分和子網掩碼的關系是怎樣

1、Service & SupportwcnP1-12（填寫文檔類型：常問問題）對于 IP 地址范圍以及子網劃分，IP 地址和子網掩碼的關系是怎樣的？組態(tài)事項:使用 CIDR，不用為 IP 地址分配網絡類別，也不用為子網或超網分配類別，僅有一個子網掩碼把 IP 地址分開成主機部分和網絡部分。CIDR 功能(無類別域間路由) 包括子網和超網。以下列表列出了支持子網和超網兩種功能的工業(yè)以太網 CPs：6GK7 343-1EX11-0XE0 - 不支持 CIDR 功能6GK7 343-1EX20-0XE0 - 支持 CIDR 功能6GK7 343-1EX21-0XE0 - V1.2 以上固件版本支持 C

2、IDR 功能6GK7 343-1EX30-0XE0 - 支持 CIDR 功能6GK7 343-1GX20-0XE0 - 不支持 CIDR 功能6GK7 343-1GX21-0XE0 - V1.1 以上固件版本支持 CIDR 功能6GK7 343-1GX30-0XE0 - 支持 CIDR 功能6GK7 343-1CX00-0XE0 - 不支持 CIDR 功能6GK7 343-1CX10-0XE0 - 支持 CIDR 功能6GK7 443-1EX10-0XE0 - 不支持 CIDR 功能6GK7 443-1EX11-0XE0 - 不支持 CIDR 功能6GK7 443-1EX20-0XE0 - 支

3、持 CIDR 功能6GK7 443-1EX40-0XE0 - V2.4 以上固件版本支持 CIDR 功能6GK7 443-1EX41-0XE0 - 支持 CIDR 功能6GK7 443-1GX20-0XE0 - 支持 CIDR 功能www PLCworld cnS7-300 和 S7-400 CPUs 集成的 PROFINET 接口：CPU 315-2PN/DP 及 CPU 315F-2PN/DP - V2.3 以上固件版本支持 CIDR 功能CPU 317-2PN/DP 及 CPU 317F-2PN/DP - V2.3 以上固件版本支持 CIDR 功能CPU 319-3PN/DP - 支持

4、CIDR 功能CPU 414-3PN/DP - 支持 CIDR 功能CPU 416-3PN/DP 及 CPU 416F-3PN/DP - 支持 CIDR 功能以下工業(yè)以太網 PC 模塊支持子網和超網兩種功能：CP1616 V2.0 固件版本CP1604 V2.0 固件版本通過工業(yè)以太網 PC 模塊例如 IE general, CP1613 (A2), CP1623, CP1612 及 CP1512 僅能組態(tài) 子網功能，但是不能在 STEP 7 / NCM PC 中組態(tài)超網功能，這將會在 STEP 7 / NCM PC 產生錯誤信息（見圖 5）支持 TCP/IP 協議的工業(yè)以太網CP 模板或 C

5、PU，可以在 STEP7 硬件組態(tài)中設置 IP 地址和相關的子網掩碼。該 IP 地址和相應的子網掩碼可以在CP 模板或 CPU 的以太網接口的屬性窗口中設置。在硬件組態(tài)插入 CP 模板或CPU 后，在它們的屬性窗口會得到下面的默認設置 (圖. 01)。IP 地址: 子網掩碼: Service & SupportwcnP2-12（填寫文檔類型：常問問題）圖. 01: CP 模板以太網屬性窗口需要改變默認的 IP 地址和子網掩碼，需要ww了w P解LCwIPorld地cn址和子網掩碼的分類關系，以下清楚描述了IP 地址和子網掩碼的分類關系。IP 地址和子網掩碼分類關系:原則上 IP 地址分為 5

6、類，從 AE。每一類都有自己的子網掩碼。如下表所示。A 類網絡：A 類的 IP 地址以位 0-.開始，例如 IP 地址范圍從 0.x.x.x 到 127.x.x.x。子網掩碼標識一個子網的地址范圍信息。對于 A 類網絡，第一個字節(jié)，也就是頭 8 位對應 IP 地址的子網地址。所以 A 類網絡由以下的子網掩碼定義： = 1111 1111 0000 0000 0000 0000 0000 0000。IP 地址的后 3 個字節(jié)(24 位)用于識別網絡上的主機。A 類網絡按照下面方法計算子網個數：28-1 = 27 = 128 個子網 (因為 A 類 IP 地址以位 0 開始) A 類網絡按照下面方

7、法計算節(jié)點個數：224 = 16 777 216 個節(jié)點類表示類的位IP 網絡地址范圍子網掩碼網絡 ID節(jié)點 IDA0 xxxxxxx0.x.x.x - 127.x.x.x1 字節(jié)3 字節(jié)B10 xxxxxx128.0.x.x - 191.255.x.x2 字節(jié)2 字節(jié)C110 xxxxx192.0.0.x - 223.255.255.x3 字節(jié)1 字節(jié)D & E111xxxxx-55-組播地址wcnP3-12（填寫文檔類型：常問問題）Service & Support圖. 02: A 類網絡B 類網絡:B 類的 IP 地址以位 1-0-.開始，IP 地址范圍從 128.0.x.x 到 191

8、.255.x.x。對于 B 類網絡，頭兩個字節(jié)，也就是頭 16 位對應 IP 地址的子網地址。所以 B 類網絡由以下的子網掩碼定義： = 1111 1111 1111 1111 0000 0000 0000 0000。 IP 地址的后 2 個字節(jié)(16 位)用于識別網絡上的主機。 B 類網絡按照下面方法計算子網個數：216-2 = 214 = 16384 個子網 (因為 B 類 IP 地址以位 1-0 開始) B 類網絡按照下面方法計算節(jié)點個數：216 = 65536 個節(jié)點www PLCworld cn圖. 03: B 類網絡C 類網絡:C 類的 IP 地址以位 1-1-0-.開始，IP 地

9、址范圍從 192.0.0.x 到 223.255.255.x。對于 B 類網絡，頭三個字節(jié)，也就是頭 24 位對應 IP 地址的子網地址。所以C 類網絡由以下的子網掩碼定義： = 1111 1111 1111 1111 1111 1111 0000 0000。IP 地址的后 1 個字節(jié)(8 位)用于識別網絡上的主機。C 類網絡按照下面方法計算子網個數：224-3 = 221 = 2 097 152 個子網 (因為 C 類 IP 地址以位 1-1-0 開始) B 類網絡按照下面方法計算節(jié)點個數：28 = 256 個節(jié)點圖. 04: C 類網絡D 類子網:D 和 E 類是用于網絡組播和廣播的特殊地

10、址。劃分 IP 地址的子網部分和節(jié)點部分得到以下結論：wcnP4-12（填寫文檔類型：常問問題）Service & Support對于節(jié)點部分，A 類網絡的節(jié)點數是大大多于C 類網絡的。對于子網部分，A 類網絡的子網數是大大少于C 類網絡的。預留地址:A 類網絡地址 127.x.x.x 保留用于所有計算機的回環(huán)功能，即:所有第一個字節(jié)為 127 的 IP 地址僅用于計算機的內部測試。255 被保留作為廣播地址。例如，地址 55 是一個對于B 類網絡 中所有計算機的一個廣播地址。下列地址范圍保留用于私有網絡，所有這些 IP 地址在 Internet 上是不能路由的。 - 55 - 55 - 55

11、到現在為止，解釋了 IP 地址和子網掩碼的分類的關系。另外，也可以通過劃分子網的方法來擴展子網掩碼。劃分子網:例如，在 A 類網絡中劃分子網，可以在 A 類的網絡中進一步劃分邏輯單元（子網）。例如 A 類網絡 IP地址 86.x.x.x，A 類網絡的子網掩碼是 (1111 1111 0000 0000 0000 0000 0000 0000). 通過擴展子網掩碼的 1 位，地址區(qū)間可以進一步劃分邏輯子網，那么子網掩碼為 (1111 11111000 0000 0000 0000 0000 0000)。以下用于尋址：僅地址 到 54 可以相互直接通訊，即不通過路由器，因為這些計算機在子網掩碼后的

12、第一位為相同的值 (這里 0) 。僅地址 到 54ww可w 以PLC相wo互rld直cn 接通訊，即不通過路由器，因為這些計算機在子網掩碼后的第一位為相同的值 (這里 1)A 類網絡的計算機地址域被分為 2 個子網。結論:通過擴展子網掩碼，可以把計算機的地址域劃分為多個邏輯單元（子網）。如上地址域分為 2 個子網。通過增加更多的位，可以增加子網的個數?？梢愿鶕柙黾幼泳W。超網:超網是把多個網絡組合成一個網絡。超網在技術上和子網相反，原則上把多個主機放在一個 IP 網絡。使用超網，共享主機增加，網絡類別減少。以 C 類網絡 為例 。子網掩碼是 (1111 1111 1111 1111 1111

13、 11110000 0000)?，F在增加兩位作為主機共享。子網掩碼就是 (1111 1111 1111 1111 11111100 0000 0000).分配的最低網絡 IP 地址是： (1111 1111.1111 1111. 1011 0000. 0000 0001)分配的最高網絡 IP 地址是：54 (1111 1111.1111 1111. 1011 0011. 1111 1110)從 到 54 可以不經過路由互相通訊。要求:超網 的使用要求網絡中有支持無類別域間路由 (CIDR)功能的模塊。注意:若在 STEP 7 中組態(tài)的模塊不支持子網或超網功能，使用該功能將會在 STEP 中產生

14、錯誤信息 (見圖 05 STEP 7 錯誤信息)。定義子網掩碼可能以 = 1111 1111 0000 0101 0000 0000 0000 0000 這種形式出現。這里用于地址尋址的不是兩個連續(xù)的位，而是任意兩個其它的位。由于這種方式很難去把握并且可能會出現很多錯誤，強烈建議不使用這樣的子網掩碼。STEP 7 在組態(tài)CP 卡以太網接口屬性中不允許設置這樣wcnP5-12（填寫文檔類型：常問問題）Service & Support的子網掩碼。下面是出現錯誤信息：www PLCworld cn圖. 05: STEP 7 錯誤信息子網掩碼必須包含一系列連續(xù)的 1，中間不能有 0 間隔。STEP

15、7 在線幫助給出下列信息。wScroll down for English:cnP6-12（填寫文檔類型：常問問題）What is the connection between subnet masks and IP addresses in the IP address area, also with regard to subnetting?Configuration Notes:With CIDR, there is no fixed assignment of an IP address to a network class and possible subnetting in oth

16、er networks or supernetting of several networks in a class. There is only one network mask that splits the IP address into a network part and a host part.The CIDR function (classless inter domain routing) thus includes subnetting and supernetting. The following list shows you which Industrial Ethern

17、et CPs support the two functions of subnetting and supernetting:6GK7 343-1EX11-0XE0 - does not support the CIDR function6GK7 343-1EX20-0XE0 - supports the CIDR function6GK7 343-1EX21-0XE0 - supports the CIDR function from firmware V1.2 onwards6GK7 343-1EX30-0XE0 - supports the CIDR function6GK7 343-

18、1GX20-0XE0 - does not support the CIDR function6GK7 343-1GX21-0XE0 - supports the CIDR function from firmware V1.1 onwards6GK7 343-1GX30-0XE0 - supports the CIDR function6GK7 343-1CX00-0XE0 - does not support the CIDR function6GK7 343-1CX10-0XE0 - supports the CIDR function6GK7 443-1EX10-0XE0 - does

19、 not support the CIDR function6GK7 443-1EX11-0XE0 - does not support the CIDR function6GK7 443-1EX20-0XE0 - supports the CIDR function6GK7 443-1EX40-0XE0 - supports the CIDR function from firmware V2.4 onwardsService & Support圖 06: STEP 7 在線幫助#Ende#號:2073614www PLCwor日ld c期n :2009-01-28wcnP7-12（填寫文檔

20、類型：常問問題）Service & Support6GK7 443-1EX41-0XE0 - supports the CIDR function6GK7 443-1GX20-0XE0 - supports the CIDR functionand for the S7-300 and S7-400 CPUs with integrated PROFINET interface:CPU 315-2PN/DP and CPU 315F-2PN/DP - support CIDR from firmware V2.3 onwardsCPU 317-2PN/DP and CPU 317F-2PN/D

21、P - support CIDR from firmware V2.3 onwardsCPU 319-3PN/DP - supports CIDRCPU 414-3PN/DP - supports CIDRCPU 416-3PN/DP and CPU 416F-3PN/DP - support CIDRThe following Industrial Ethernet PC modules support the functions of subnetting and supernetting:CP1616 from V2.0CP1604 from V2.0It is only possibl

22、e to configure the Subnetting function for the remaining Industrial Ethernet PC modules like IE general, CP1613 (A2), CP1623, CP1612 and CP1512. It is not possible to configure the Supernetting function in STEP 7 / NCM PC for these modules. This is prevented in STEP 7 / NCM PC by an error message (s

23、ee Fig. 05).In these modules that support the TCP/IP protocol it is possible to set both the IP address and the associated subnet mask in the hardware configuration of STEP 7. The IP address and associated subnet mask are entered in the Properties window of the CPs or CPUs Ethernet interface. After

24、inserting the Industrial Ethernet CP or CPU with integrated PN interface in the hardware configuration, you are offered the following default settings (see Fig. 01) in the Properties window of the CPs or CPUs Ethernet interface.IP address: Subnet mask: www PLCworld cnService & SupportwcnP8-12（填寫文檔類型

25、：常問問題）Fig. 01: Properties window of a CPs Ethernet interfaceIf you wish to change these default settings for the IP address and subnet mask, you need information on the connection between classes of IP addresses and subnet masks. The following makes clear the connection between classes of IP address

26、es and subnet masks.Connection between class of the IP address and subnet mask:In principle there are 5 classes of IP addresses. These are the classes A to E. Each class has its own subnet mask. The connections are given in the table below.Class A network:IP addresses from Class A begin with the bit

27、 sequence 0-., e.g. the IP address range lies between0.x.x.x and 127.x.x.x.The subnet mask identifies the range that includes the address information for identifying the subnet. In Class A networks the first byte, that is to say the first 8 bits correspond to the IP address of the subnet address. Th

28、us Class A networks are defined by the following subnet mask: = 1111 1111 0000 0000 0000 0000 0000 0000. The last three bytes (24 bits) of the IP address identify a node in this subnet.The total number of Class A networks can be calculated as follows:28-1-2 = 27-2 = 126 networks (since the IP addres

29、s always begins with the bit sequence 0-., and are not permitted)number of computers in a Class A network can be calculated as follows:www PLCworld cn224-2 = 16 777 214 computers (x.0.0.0 - network address and x.255.255.255 - broadcast address are not permitted)Fig. 02: Class A networkClass B networ

30、k:IP addresses from Class B begin with the bit sequence 1-0-. and the address range lies between128.0.x.x and 191.255.x.x. In Class B networks the first two bytes, that is to say the first 16 bits correspond to the IP address of the subnet address. Thus Class B networks are defined by the following

31、subnet mask: = 1111 1111 1111 1111 0000 0000 0000 0000. The last two bytes (16 bits) identify a node in this subnet.The total number of Class B networks can be calculated as follows:216-2 = 214 = 16384 networks (since the IP address always begins with the bit sequence 1- 0.)The number of computers i

32、n a Class B network can be calculated as follows:216-2 = 65534 computers (x.x.0.0 - network address and x.x.255.255 - broadcast address are not permitted)ClassClass bitsIP network address rangeSubnet maskNetwork shareComputer shareA0 xxxxxxx0.x.x.x - 127.x.x.x1 byte3 bytesB10 xxxxxx128.0.x.x - 191.2

33、55.x.x2 bytes2 bytesC110 xxxxx192.0.0.x - 223.255.255.x3 bytes1 byteD & E111xxxxx-55-Multicasting addresseswcnP9-12（填寫文檔類型：常問問題）Service & SupportFig. 03: Class B networkClass C network:IP addresses from Class C begin with the bit sequence 1-1-0. and the address range lies between192.0.0.x and 223.25

34、5.255.x. In Class C networks the first three bytes, that is to say the first 24 bits correspond to the IP address of the subnet address. Thus Class C networks are defined by the following subnet mask: = 1111 1111 1111 1111 1111 1111 0000 0000. The last byte (8 bits) identifies a node in this subnet.

35、The total number of Class C networks can be calculated as follows:224-3 = 221 = 2 097 152 networks (since the IP address always begins with the bit sequence 1-1-0.)The number of computers in a Class C network can be calculated as follows:28-2 = 254 computers (x.x.x.0 - network address and x.x.x.255

36、- broadcast address are not permitted)www PLCworld cnFig. 04: Class C networkClass D subnetwork:The class D subnetwork consists of special addresses that are used for multicast addressing. This splitting up of IP addresses in network share and computer share leads to the following conclusions:A Clas

37、s A network is larger than a Class C network, because there is a much greater address area available for addressing the computers.There are much less Class A networks than Class C networks because the address area of the subnets is much smaller.Reserved addresses:The Class A network address 127.x.x.

38、x is reserved for the Loopback function of all computers, i.e.:all IP addresses that have the value 127 in the first byte may only be used for internal tests of computers.The 255 values are reserved as broadcast addresses. Thus, for example, the address 55 is a broadcast address to all computers in

39、the Class B network .The following ranges are reserved for private networks. All IP addresses in these ranges are not routed in the Internet. - 55 - 55wcnP10-12（填寫文檔類型：常問問題）Service & Support - 55Until now, the connection between the class of the IP address and subnet mask has been explained. Further

40、more, it is possible to extend the subnet mask with the so-called subnetting procedure.Subnetting:Subnetting can be implemented in a Class A network, for example. It is possible to divide the computers of this Class A network into further logical units (subnets). We will observe the Class A network

41、86.x.x.x as an example. The subnet mask of this Class A network is (1111 1111 0000 0000 0000 0000 0000 0000). The address area can be divided further into logical subnets byextending the subnet mask by 1 bit. The subnet mask is then (1111 1111 1000 00000000 0000 0000 0000).This means the following f

42、or addressing:Only the addresses to 54 can communicate directly with each other,i.e. without router, because these computers have the same value (in this case 0) in the first bit after the subnet mask.Only the addresses to 54 can communicate directly with each other,i.e. without router, because thes

43、e computers have the same value (in this case 1) in the first bit after the subnet mask.The address area of the computers in this Class A network has been divided into two subnets.Conclusion:By extending the subnet mask you can divide the address area of the computers into more logical units (subnet

44、s). The address area has been divided into two subnets in the example. By adding more bits you can quickly multiply the number of subnets. You can extend a subnet as you wish.Supernetting:Supernetting is the grouping together of multiple networks with partially the same network share in single route

45、. The underlying technology is the opposite to subnetting and in principle means a edure for addressing a large number of hwowswtPsLCwwiothrldincnone IP network. With supernetting the hostshare of a network class is increased. Thus the network share of this network class is decreased. We will observe the Class C network as an example. The subnet mask of this Class C network is (1111 1111 1111 1111 1111 1111 0000 0000). Now 2 bits are added to thehost s