What is NBMA

The internet

NBMAEarly in the CCNA to have contact，Only the name has no concept of，This may be said to be the fault of the translation，After all, the back of his translation did not add parentheses correspond to write about the English name ...... ah，At least not write the full name。so，If I do change itNon-Broadcast Multiple AccessWhen you know，Yes，NBMA is a non-broadcast multiple accessAbbreviation。

Stands fornon-broadcastmultipleaccess，MBA is the corresponding，Naturally, it is broadcastmultipleaccess，That is,wide[……]

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OSX on update after the "failed to load the preference pane" security and privacy "," solution

Mac OS

In the updated10.9formal editionafter that，FindSystem PreferencesPanelSecurity & PrivacyOptions somehow not open，Prompted：

Failed to load preferences pane "security and privacy"

Solution

Open your "other"Folder"Font Book"application，as the picture shows

 

Then find all the words "shut down"Font turn them to open!

 

You do not even have to restart your computer，"Security and privacy" Now you can use!

Other，A friend asked,[……]

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Port roles RSTP Rapid Spanning Tree Protocol：Alternate ports and backup ports

The internet

existRSTP (Rapid Spanning Tree Protocol)Learning which，We will know RSTP different fromPVST (Per Vlan Spanning Tree)One of the places，It isPort Roles difference。As different port states believe everyone is familiar with，But the problem of port role，Many books and tutorial included in the classroom are a passing，In retrospect，Students can not help knowing a lot of questions，Let's take a look at this，Among the Rapid Spanning Tree Protocol，Exactly what role the port and the two often talked aboutAlternate ports and backup portsWhat is emerging。

Rapid Spanning Tree Protocol RSTP port[……]

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Problems when running IGP IBGP encounter：BGP routing updates only the best entries

The internet

BGP recently doing exercises，Do the following topology when encountered some problems，This topology is

I configured the network segment：

among them

[cr[……]

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How EIGRP publish static routes

The internet

In the EIGRP routing protocol，It does not seem to be able to issue commands directly to the default route，例如default-information originate

 

That should be how to do it? Here are two common methods：

one、Write a static default route，Then use the command to redistribute default route into EIGRP filling inside，Displaying such route entry for "D * EX" default administrative distance of 170；

 

two、Write a static default route，Then[……]

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OSPF link regional accreditation and certification (Port Authentication) difference

The internet

In the configuration in OSPF，There are portions of the content certification，OSPF authentication is divided into two，They are

  • Based authentication area
  • Based authentication link (port)

The same time，Authentication mode can also be divided into two，One is plain text authentication，Another is the MD5 encrypted authentication。

Here we do not discuss OSPF encryption method，It is simply illustrative ofRegional links and similarities and differences between these two types of authentication。

We agreed to a topology map，Probably like this

R1(s0 / 0)—–(s0 / 0)R2(s0 / 1)—-[……]

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OC: Optical Carrier Optical Carrier

Exchange of Experience The internet

OC standard fiber cable is commonly used in today's networks set of standards，Readily not hurt to look at memory。

Optical Carrier (OC) is determined at a level many SONET fiber optic network of a group of signal bandwidth。It is usually expressed as OC-n，among them，n is a multiplication factor，It indicates basic rate is 51.84 Mbit / s the number of times。Currently defined standards：
OC-1 — 51.8 4Mbit/s
OC-3 — 155.52 Mbit/s
OC-12 — 622.08 Mbit/s

[……]

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Yum install open source package management tool developers death due to accident

Linux

For all systems administrator，Today the news is quite regrettable。Open source command line package management tool developer of yum Seth Vidal when riding a bicycle was hit by a car and killed，Age of 36。Currently the driver still escape。

Yum(Full name Yellow dog Updater, Modified) Is anFedoraandRedHatas well asSUSE、CentOSThe front-end package manager Shell。based onRPMPackage Management，Can be automatically downloaded from the specified serverRPMAnd the installation package[……]

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