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伊林思_工业无线路由器OSPF链路类型(Link... 工业无线路由器OSPF链路类型(Link Type) 巧玲珑OSPF确实因为考虑问题的全面,而导致路由协议的复杂,OSPF不仅因为不同的二层链路层介质定义了不同的OSPF网络类型(Network Type),还因为链路上的邻居,而定义了OSPF链路类型(Link Type) 。 OSPF网络类型(Network...

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工业路由器的Network Summary LSA 工业路由器:Network Summary LSA ABR工业级路由器始发,用于通告该区域外部的目的地址, 可以使用show ip ospf database summary查看LSA 如果ABR知道有多条路径可以到达目标地址,但是它仍然只发送单个的Network Summary LSA,并且是开销最低的那条;同样,如果ABR从其他的ABR那里收到多条Network...

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工业4G路由器BGP邻居的flaping •工业路由器通过IGP学到对方loopback,并用looback建EBGP邻居 •又在BGP中通告此loopback。此时BGP邻居会出现flaping R1和R2之间运行一个IGP协议,比如说EIGRP。将环回口都宣告进去,这样R1和R2相互之间就有对方环回口的工业级路由器路由了,然后再用环回口建立EBGP邻居关系。最后再把2.2.2.0和1.1.1.0的环回口宣告进BGP。这时你会发现工业无线路由器BGP路由会发生flapping。 原因一:无线路由器 •首先R1和R2之间运行了EIGRP,学到对方的环回口工业级无线路由器路由是一条EIGRP路由,管理距离是90 •而当这两个环回口宣告进BGP后,R1和R2又通过BGP学到对方环回口路由,管理距离是20 •这时,全网工业级路由器BGP路由由于管理距离最小,会进入全网工业路由器路由表,取代EIGRP路由 •问题在于,现在的全网通工业路由器BGP路由是有问题的,下一跳是不可达的 R2收到的1.1.1.0的BGP路由下一跳是R1的环回口1.1.1.1 R1收到的2.2.2.0的BGP路由下一跳是R2的环回口2.2.2.2 •BGP有一个检查机制,每60S检查一次BGP路由,看是否有效,60S后就会检查到这些工业级全网通路由器路由并设为无效 •BGP路由无效以后,在路由表中就没有了,EIGRP路由又起作用了。 •有了EIGRP路由,BGP路由的下一跳有可达了。又有效了。 •BGP邻居有效以后,又会抢占了EIGRP路由的地位,又会导致全网通工业级路由器BGP路由下一跳不可达。 原因二:4g路由器 •首先R1和R2之间运行了EIGRP,学到对方的环回口工业全网通路由器路由是一条EIGRP路由,管理距离是90 •而当这两个环回口宣告进BGP后,R1和R2又通过BGP学到对方环回口路由,管理距离是20 •这时,工业级全网路由器BGP路由由于管理距离最小,会进入路由表,取代EIGRP路由 •问题在于,现在的工业4G路由器BGP路由是有问题的,下一跳是不可达的 R2收到的1.1.1.0的工业级4G路由器BGP路由下一跳是R1的环回口1.1.1.1 R1收到的2.2.2.0的BGP路由下一跳是R2的环回口2.2.2.2 •路由不可达就造成两个邻居之间没法发送keeplive •180S后BGP邻居关系超时,并DOWN掉。这时EIGRP路由又起作用了。 •有了EIGRP路由,BGP邻居关系又可以建立了。 •BGP邻居有效以后,工业全网路由器BGP路由又会抢占了EIGRP路由的地位,又会导致BGP邻居再一次DOWN掉。 标签:全网通路由器 ...

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工业路由器OSPF建立邻居到LSA的互换的交换过程 从工业路由器OSPF建立邻居,到LSA的互换,到路由表的计算,需要经过一系列的工业级路由器数据包交换过程,过程如下: Hello ↓ Database Description Packets (DBD) ↓ Link-state Request (LSR) ↓ Link-state update(LSU) ↓ LSDB 具体情况如下: Hello Hello包是用来建立和维护工业无线路由器OSPF邻居的,要交换LSA,必须先通过Hello包建立工业级无线路由器OSPF邻居。 Database...

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伊林思:工业4g路由器区域分离你清楚吗? 工业4g路由器区域分离 区域分离的操作与区域合并的正好相反。区域分离可以将原有的一个区域分离为两个不同的区域。如下图所示,R1与R2都为L1/2工业路由器。起初R1和R2属于同一个区域中,都拥有相同的区域地址49.0001,之间形成了L1和L2邻接关系,共享相同的L1和L2链路状态数据库。现在需要将这两个区域分离开。与区域合并一样,可以先赋予R2两个全网通工业路由器NET地址,区域地址分别为49.0001和49.0002。之后再将R2原先区域地址为49.0001的NET地址删除,这时由于R1和R2处于不同的区域,L1邻接关系将不存在,但L2邻接关系和L2链路状态数据将保留,此时便完成了全网通工业级路由器区域分离。 重编址 重编址过程与区域合并、区域分离相似,重编址可能需要清除一些或者全部工业级路由器的区域前缀,用新的区域前缀代替。如下图所示,现在希望将原先的49.0001区域迁移到49.0002区域,这就需要更改工业级无线路由器上的区域地址。R1和R2属于同一个区域49.0001中,要将R1和R2迁移到49.0002区域中,可以为R1和R2都赋予两个NET地址,两个NET地址包含不同的区域地址,49.0001和49.0002,然后依次删除R1和R2的包含49.0001区域地址的NET地址,这样就实现了工业无线路由器新的NSAP地址的无缝、无冲突的重新配置。 注意,IS-IS多宿主与IP中的辅助地址(secondanaryIP)是不同的,辅助地址可以在同一条工业级全网通路由器链路上创建多个隔离的逻辑子网。另外,辅助IP地址是在一条链路上配置多个子网。 工业无线路由器NSEL NSEL定义了网络层服务的用户,工业全网通路由器路由层是特殊的网络层服务用户,它的NSEL值为0。之前多次提到,在IS-IS工业4G路由器上配置的NSAP地址采用00作为NSEL,这时NSAP地址被称为NET。NSEL的值与IP报头中的协议类型或TCP/UDP报头中的TCP、UDP端口号类似,NSEL帮助网络层把数据发送到适当的应用程序或服务。在OSI分层模型中,网络层服务的是传输层。目标不是路由进程的CLNP数据包具有非0的NSEL值的NSAP地址,表示节点需要将数据发送到传输层。我们在使用IS-IS进行工业级4G路由器IP路由选择中,只要记住始终保持NSEL为00即可。全网通4g路由器

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A Quick Understanding of FTP/SFTP/FTPS/TFTP

Category : 伊林思产品FAQ, 其他, 技术相关

File Transfer Protocol (FTP)

The File Transfer Protocol (FTP) is a standard network protocol used for the transfer of computer files from a server to a client using the Client–server model on a computer network.

FTP is built on a client-server model architecture and uses separate control and data connections between the client and the server. FTP users may authenticate themselves with a clear-text sign-in protocol, normally in the form of a username and password, but can connect anonymously if the server is configured to allow it. For secure transmission that protects the username and password, and encrypts the content, FTP is often secured with SSL/TLS (FTPS). SSH File Transfer Protocol (SFTP) is sometimes also used instead; it is technologically different.

 

SSH File Transfer Protocol(SFTP)

The SSH file transfer protocol (chronologically the second of the two protocols abbreviated SFTP) transfers files and has a similar command set for users, but uses the Secure Shell protocol (SSH) to transfer files. Unlike FTP, it encrypts both commands and data, preventing passwords and sensitive information from being transmitted openly over the network. It cannot interoperate with FTP software.

In computing, the SSH File Transfer Protocol (also Secure File Transfer Protocol, or SFTP) is a network protocol that provides file access, file transfer, and file management over any reliable data stream. It was designed by the Internet Engineering Task Force (IETF) as an extension of the Secure Shell protocol (SSH) version 2.0 to provide secure file transfer capabilities. The IETF Internet Draft states that, even though this protocol is described in the context of the SSH-2 protocol, it could be used in a number of different applications, such as secure file transfer over Transport Layer Security (TLS) and transfer of management information in VPN applications.

This protocol assumes that it is run over a secure channel, such as SSH, that the server has already authenticated the client, and that the identity of the client user is available to the protocol.

Simple File Transfer Protocol

Simple File Transfer Protocol (the first protocol abbreviated SFTP), as defined by RFC 913, was proposed as an (unsecured) file transfer protocol with a level of complexity intermediate between TFTP and FTP. It was never widely accepted on the Internet, and is now assigned Historic status by the IETF. It runs through port 115, and often receives the initialism of SFTP. It has a command set of 11 commands and support three types of data transmission: ASCII, binary and continuous. For systems with a word size that is a multiple of 8 bits, the implementation of binary and continuous is the same. The protocol also supports login with user ID and password, hierarchical folders and file management (including rename, delete, upload, download, download with overwrite, and download with append).

FTPS

Explicit FTPS is an extension to the FTP standard that allows clients to request FTP sessions to be encrypted. This is done by sending the “AUTH TLS” command. The server has the option of allowing or denying connections that do not request TLS. This protocol extension is defined in RFC 4217. Implicit FTPS is an outdated standard for FTP that required the use of a SSL or TLS connection. It was specified to use different ports than plain FTP.

Trivial File Transfer Protocol(TFTP)

Trivial File Transfer Protocol (TFTP) is a simple, lock-step FTP that allows a client to get a file from or put a file onto a remote host. One of its primary uses is in the early stages of booting from a local area network, because TFTP is very simple to implement. TFTP lacks security and most of the advanced features offered by more robust file transfer protocols such as File Transfer Protocol. TFTP was first standardized in 1981 and the current specification for the protocol can be found in RFC 1350.

 

 (Information collected from Wekipedia)

E-Lins Antenna Catalog

Category : 产品文章, 其他

Usually magnetic antenna is used for our 3G/4G routers. It has 3dbi, 5dbi, 7dbi, 9dbi and 11dbi. 3dbi is in standard packing, if router will be applied in rural place, high gain antenna is for optional.

 

wifi吸盘1

Sometimes, you don’t want this long antenna with cable, you also can choose rubber antenna, which is small and powerful.

rubber-antenna1

We also have wall mounted antenna, panel antenna, glass fiber antenna and so on, for further information, please check:

http://www.e-lins.com/EN/download/E-Lins_Antenna_Catalog.pdf

E-Lins FAQ — POE

Category : 产品文章, 伊林思产品FAQ, 其他, 技术相关

Q: Does your router support POE option? How does it work?

A: Yes, E-lins H685 series, H700 series and H720 series routers support POE option.

It works as following chart.

POE

 

Antenna Gain

Category : 其他

For a better understanding about antenna gain, you can go through this article.

Antenna gain is often quoted with respect to a hypothetical antenna that radiates equally in all directions, an isotropic radiator. This gain, when measured in decibels, is called dBi. Conservation of energy dictates that high gain antennas must have narrow beams. For example, if a high gain antenna makes a 1 watt transmitter look like a 100 watt transmitter, then the beam can cover at most 1/100 of the sky (otherwise the total amount of energy radiated in all directions would sum to more than the transmitter power, which is not possible). In turn this implies that high-gain antennas must be physically large, since according to the diffraction limit, the narrower the beam desired, the larger the antenna must be (measured in wavelengths).

Antenna gain can also be measured in dBd, which is gain in Decibels compared to the maximum intensity direction of a half wave dipole. In the case of Yagi type aerials this more or less equates to the gain one would expect from the aerial under test minus all its directors and reflector. It is important not to confuse dBi and dBd; the two differ by 2.15 dB, with the dBi figure being higher, since a dipole has 2.15 db of gain with respect to an isotropic antenna.

Gain is also dependent on the number of elements and the tuning of those elements. Antennas can be tuned to be resonant over a wider spread of frequencies but, all other things being equal, this will mean the gain of the aerial is lower than one tuned for a single frequency or a group of frequencies. For example, in the case of wideband TV antennas the fall off in gain is particularly large at the bottom of the TV transmitting band. In the UK this bottom third of the TV band is known as group A, see gain graph comparing grouped aerials to a wideband aerial of the same size/model.

Other factors may also affect gain such as aperture (the area the antenna collects signal from, almost entirely related to the size of the antenna but for small antennas can be increased by adding a ferrite rod), and efficiency (again, affected by size, but also resistivity of the materials used and impedance matching). These factors are easy to improve without adjusting other features of the antennas or coincidentally improved by the same factors that increase directivity, and so are typically not emphasized.

E-Lins router has stardard 3dbi cellular antenna. This is enough for normal use. If you want to put it in rural place or place with bad reception, it’s better to get a high gain antenna.