Chief Transmission and Switching Engineer(JP

Let's do study and measures of "Telecommunication chief engineer examination" where a good teaching material doesn't exist though the examination contents is advanced little by little.

2010/09/28

Were you disgusted at ATM adaptation layer?

Well, the material of the study of today's chief telecommunications engineer is an ATM, too. The ATM and the adaptation layer call AAL for short today. AAL is a layer that hits the sub-layer in OSI reference model's data link layer. When you allow me to quote the explanation of the type of AAL from Wiki easily

AAL1 connection type and constant bit rate. Standard for communication of mass animation such as video conferencing telephones. To use one octet of payloads for the control of the order of transmitting the cell, real data becomes 47 octets. It is used in premises LAN.

AAL2 connection type and variable bit rate. Standard for low-speed voice sign. It is allowed to multiplex two or more traffic to one cell to decrease jitter's (swing the delay) influence by assembly and the restoration of the cell, and to send before the cell is filled.

AAL3/4 connectionless type and constant bit rate. Standard for for data communication. AAL3 and AAL4 were integrated by moving the connection setting to a high-ranking layer though it originally proposed AAL3 as a connection type and AAL4 was proposed as a connectionless type. To use four octets of payloads for high-ranking layer PDU information, real data becomes 44 octets.

AAL5 connectionless type and variable bit rate. Standard by which AAL3/4 is simplified. All payloads can be used for real data by assuming a positional detecting function of a high-ranking layer to be only a finality part. It is widely used as large area LAN with Ethernet over ATM, IP over ATM, and PPPoA (Point-to-Point Protocol over ATM). ・・・. It is so. Then, it is based and today's material is [kochira] ↓↓.




- ATM adaptation layer (AAL)



The leased circuit service etc. are used to communicate on the ATM network being classified into service class A pseudo.. resemblance of existing line service for the communication of the fixed speed type. AAL type 1

These sentences are correct.
- AAL type 1 It communicates like the leased circuit service etc. on the ATM network being classified into service class A for the communication = fixed speed type by pseudo.. resemblance of existing line service.



AAL type 2 is used to communicate of the real time character's at a changeable speed not being demanded ..for a low-speed voice-data communication...

These sentences are wrong.
- AAL type 2 is for a low-speed voice-data communication, and real time AAL for the communication from which the character is demanded at a changeable speed.
- Type 2 is low-speed though type 1 is a fixed speed at a changeable speed ・・・ However, the character is in real time demanded naturally because it uses it for the voice-data communication.




AAL type 3/4 is hardly used from becoming of AAL type 5 with few overheads or more the main current for the data communication for the data communication.

These sentences are correct.
- The AAL type is hardly used from becoming of AAL type 5 with few overheads or more the main current for the data communication for 3/4= data communication.



Isn't today's problem comparatively comprehensible?However, correct sentences that become livers of the layer, changing sentences for a moment in the part like "Extra", and setting questions do doing by being ・・・ Then, around here today

2010/09/24

Outline of connected processing of SIP used with VoIP net

Well, because the knowledge of SIP has the part that is already common sense in the network industry and the telecom industry, the chief telecommunications engineer's examination knows the minimum any more though thinks the problem of SIP to be frequent occurrence.

And, it is not the one that today's material judges "Corrections of sentences" as usual, and it is good ..only reading for the time being... The level level of today's problem doesn't become work as written at the beginning though the substantial request message of SIP if it doesn't know.

I do not understand the meaning even as for the packet capture because it will not satisfactorily use the protocol analyzer. Then, today's material is [kochira] ↓↓.



- Outline of connected processing of SIP used with VoIP net



The message of SIP includes request (demand) message and response (response) messages. As for the request message, six kinds are standardized by RFC3261 among these.

- There is request (demand) message and response (response) message = messages of SIP.



The request message of SIP is said 【 method 】 in general, and the main usage is as follows.

- In general, the request message of SIP is said 【 method 】.



A: INVITE is the first request message used to establish the session between user agent.

- The first request message used to establish the session between INVITE = user agent



B: 【ACK】 is a request message used to confirm the response message to INVITE was received, and the media session can be established by 【ACK】 for the communication.

- 【ACK】 In the request message used to confirm the response message to = INVITE was received, the media session can be established by 【ACK】 for the communication.



C: BYE can be sent from either the caller or the receiver by the request message used to end the set media session.

- It is possible to send it from either the caller or the receiver by the request message used to end the media session BYE = set.



D: CANCEL corresponds to breaking the connection before the other party responds when calling it before the media session is established by the request message used to discontinue setting.

- It corresponds to breaking the connection before the other party responds when calling it before the media session is established CANCE L = by the request message used to discontinue setting.



E: When the user agent registers 【URI】 that is my location information (location information) and Internet Protocol address to the SIP network, RESISTER is used.

- When RESISTER = user agent registers 【URI】 that is my location information (location information) and Internet Protocol address to the SIP network, it is used.



F: When the user agent inquires the ability and the state to other user agent and 【 proxy 】 server, OPTIONS is used.

- When OPTIONS = user agent inquires the ability and the state to other user agent and 【 proxy 】 server, it is used.



Well, how though this blog is not considerably seen easily because the table is not used? ..sleep.. then, a person not good at the problem related to SIP : around here today because there might be a hindrance also in the business not to mention the examination if it doesn't come to be able to judge the state by seeing "CallingSequence" though it was a problem of the request message of SIP ..study hard...

2010/09/21

About VP and VC of the ATM

Yes, I think that today's chief telecommunications engineer's material also goes by the ATM. In today's problem, virtual passing VC is a virtual channel in VP in VP and VC of the ATM. Is VP (virtual pass) a virtual transmission line in short and it only have to be thought the transmission line of the ATM and SDH?It is a group of a logical virtual line that mutually connects the edge tune. VC (virtual channel) is a road to put it briefly as shown in data. A few VC can be passed through one VP and good transmission of efficiency can be done. Then, today's material is [kochira] ↓↓.



- VP of ATM (virtual passing) and VC (virtual channel)



In the sending terminal, the VCI value in which the receiving terminal that is the address is indicated directly is set to the VCI field of the ATM cell.

These sentences are wrong.
- VCI doesn't indicate the address directly. VCI decentralization only arranges and is used only to distinguish the channel that each cell belongs in the done each switch.
- Only the VCI value shows the channel, and even the terminal is not shown.



In the method of setting VC, there is PVC method set like the SVC method and the lease line, etc. of the setting at each communication based on the contract.

These sentences are correct.
- Method of setting only SVC = to communicate, and liberating virtual channel with end of communication
- Method of assuming virtual channel to be to be remain set for a long term by PVC = contract etc.



In the ATM network where the VP crossing connection was used, VC is set with the ATM switch in the terminal of VP.

These sentences are correct.
- Naturally, the setting of VC is a switch in the terminal of VP.



VC accommodated by VP besides VC accommodated by a certain VP of the output port of the ATM switch can use the same VCI value.

These sentences are correct.
- Yes, it is possible to use it.



さて、いかがでしたか?明日からの週末も気を抜かずに伝送交換の勉強がんばってくださいね。それでは今日はこの辺で。

2010/09/20

ATM adaptation layer

Well, the material of the study of today's chief telecommunications engineer is an ATM, too. The ATM and the adaptation layer are studied today. The ATM adaptation layer is called AAL for short. AAL is a layer that hits the sub-layer in OSI reference model's data link layer.

When I am allowed to quote the explanation of the type of AAL from Wiki easily, it is AAL1 connection type and a constant bit rate. Standard for communication of mass animation such as video conferencing telephones. To use one octet of payloads for the control of the order of transmitting the cell, real data becomes 47 octets. It is used in premises LAN. AAL2 connection type and variable bit rate. Standard for low-speed voice sign. It is allowed to multiplex two or more traffic to one cell to decrease jitter's (swing the delay) influence by assembly and the restoration of the cell, and to send before the cell is filled. AAL3/4 connectionless type and constant bit rate. Standard for for data communication. AAL3 and AAL4 were integrated by moving the connection setting to a high-ranking layer though it originally proposed AAL3 as a connection type and AAL4 was proposed as a connectionless type. To use four octets of payloads for high-ranking layer PDU information, real data becomes 44 octets. AAL5 connectionless type and variable bit rate. Standard by which AAL3/4 is simplified. All payloads can be used for real data by assuming a positional detecting function of a high-ranking layer to be only a finality part. It is widely used as large area LAN with Ethernet over ATM, IP over ATM, and PPPoA (Point-to-Point Protocol over ATM). ・・・. It is so. Then, it is based and today's material is [kochira] ↓↓.



- ATM adaptation layer (AAL



The leased circuit service etc. are used to communicate on the ATM network being classified into service class A pseudo.. resemblance of existing line service for the communication of the fixed speed type. AAL type 1

These sentences are correct.
- AAL type 1 It communicates like the leased circuit service etc. on the ATM network being classified into service class A for the communication = fixed speed type by pseudo.. resemblance of existing line service.



AAL type 2 is used to communicate of the real time character's at a changeable speed not being demanded ..for a low-speed voice-data communication...

These sentences are wrong.
- AAL type 2 is for a low-speed voice-data communication, and real time AAL for the communication from which the character is demanded at a changeable speed.
- Type 2 is low-speed though type 1 is a fixed speed at a changeable speed ・・・ However, the character is in real time demanded naturally because it uses it for the voice-data communication.



AAL type 3/4 is hardly used from becoming of AAL type 5 with few overheads or more the main current for the data communication for the data communication.

These sentences are correct.
- The AAL type is hardly used from becoming of AAL type 5 with few overheads or more the main current for the data communication for 3/4= data communication.



Isn't today's problem comparatively comprehensible?However, correct sentences that become the texts of the layer, changing sentences for a moment in the part like "Extra", and setting questions do doing by being ・・・ Then, around here today

2010/09/17

About VP and VC of the ATM

Yes, I think that today's chief telecommunications engineer's material also goes by the ATM. In today's problem, virtual passing VC is a virtual channel in VP in VP and VC of the ATM. Is VP (virtual pass) a virtual transmission line in short and it only have to be thought the transmission line of the ATM and SDH?It is a group of a logical virtual line that mutually connects the edge tune. VC (virtual channel) is a road to put it briefly as shown in data. A few VC can be passed through one VP and ..[] that does good transmission of efficiency.. technique. Then, today's material is [kochira] ↓↓.



- VP of ATM (virtual passing) and VC (virtual channel)



In the sending terminal, the VCI value in which the receiving terminal that is the address is indicated directly is set to the VCI field of the ATM cell.

These sentences are wrong.
- VCI doesn't indicate the address directly. VCI decentralization only arranges and is used only to distinguish the channel that each cell belongs in the done each switch.
- Only the VCI value shows the channel, and even the terminal is not shown.



In the method of setting VC, there is PVC method set like the SVC method and the lease line, etc. of the setting at each communication based on the contract.

These sentences are correct.
- Method of setting only SVC = to communicate, and liberating virtual channel with end of communication
- Method of assuming virtual channel to be to be remain set for a long term by PVC = contract etc.



In the ATM network where the VP crossing connection was used, VC is set with the ATM switch in the terminal of VP.

These sentences are correct.
- When it curves, the setting of VC might be a switch in the terminal of VP.



VC accommodated by VP besides VC accommodated by a certain VP of the output port of the ATM switch can use the same VCI value.

These sentences are correct.
- Yes, it is possible to use it.



Well, how?It studies and the transmission exchange holds out without pulling out the nature on the weekend from tomorrow. Then, around here today.

2010/09/16

OAM function of ATM layer

Well, today's chief telecommunications engineer's material is an ATM. They are problems of behavior and the operation, etc. of the OAM cell this time though the OAM cell calls the cell that transmits information on the maintenance operation management in the cell of the ATM. Then, today's material is [kochira] ↓↓.



- OAM function of ATM layer



The warning transfer function is achieved by sending the OAM cell that displays the breakdown to VP and VC from the device that detects the breakdown of a physical layer or the ATM layer.

These sentences are correct.
- The warning transfer function: The breakdown notification is done by sending the OAM cell (AIS cell and RDI cell) that displays the breakdown to VP or VC from the device that detects the breakdown of a function, a physical layer or the ATM layer that notifies VP and VC not to be able to be used when the breakdown occurs in the transfer function of a physical layer or the ATM layer.
VP-RDI: Signal that is judged breakdown, and sent at transmitting end when user information cell or OAM cell doesn't receive it on receiving side longer than fixed time
Signal to notify direction of reception side from the connection point the breakdown when breakdown of VP-AIS:VP connection is detected



The loop back cell that receives it is sent back as it is in the device specified for a halfway mark though the connection of the communication of a specified section of arbitrary VP and VC confirmation uses the loop back function.

These sentences are wrong.
- The OAM cell for the loop back is sent from the device on the edge of the section where it wants to confirm the communication connection. The number of the device on the other edge is written in the loop back cell as a halfway mark. This loop back cell is sent in the counter direction when received with the device for which the loop back cell is specified for a halfway mark. The communication connection in a specified section is confirmed first by receiving the turned loop back cell in the device that sends the loop back cell.
- Moreover, the meaning of this explanation is not understood. 。。

- Anyway, the part of "Send it back as it is" is a mistake, and "It rewrites in a specific value and send it back" answers correctly.
- The least significant bit of the loop back display field displays whether the loop back has already been executed by the pool algebra form. It is confirmed whether the loop back is executed by this field in the ATM layer. This field is coded to "00000001" in the source point. In the loop back point, it replaces it with "00 million".



The number of cell losses and the number etc. of mistakes of VP and VC can be confirmed on the receiving side according to information on the OAM cell for the continuity check.

These sentences are wrong.
- The number of cell losses and the number etc. of sign mistakes of VP and VC cannot be confirmed by using OAM cell information for the reception side continuity check.
- Anyway, it seems to be "It is not possible to judge on the receiving side. "



The continuity check function and the performance monitoring function start/are stopped by start/stop OAM cell. Which function start/is stopped is specified in peculiar to the function of the payload field.

These sentences are wrong.
- Which function start/is stopped is specified by the OAM function type of the payload.
- Continuity check or performance monitoring function or which is used is specified by "OAM function type".



Well, how about you?It is caught to the problem if it studies really neatly, and it doesn't remember surely if it is necessary to judge the correction from either that rewrites only ending of a words of sentences and sentences that can be taken. Because frequency of setting questions is considerably high, let's work hard and remember the OAM relation in the problem of the ATM. Then, around here today

2010/09/15

Problem of ATM adaptation layer

Well, please not only do ..problem of the ATM.. specialized subject and study the problem of the transmission exchange and the plant management hard the chief telecommunications engineer's of today study though it peels off ATM because it is an item of frequent occurrence.

Then, today's material is [kochira] ↓↓.



- ATM adaptation layer (AAL) type 5



The overhead when communicating compared with other AAL types is minimum because there are neither header nor trailers in cell splitting and assembly unpleasant sable (SAR) in AAL type 5.

These sentences are correct.
- The overhead when the AAL type 5= is communicated is minimum.
- There is AAL type neither the header nor 5= trailer (To SAR).



It differs from AAL type 3/4, and it mistakes and it detects it by cyclic check sign (CRC) in ten bits in each sequence number of the cell in AAL type 5.

These sentences are wrong.
- It mistakes only because of the CRC check of CPCS-PDU after the sequence number etc. of the cell are not used for the fault sensing, and the frame is assembled and it detects it.
- Each cell mistakes, it doesn't detect, each CPCS-PDU is mistaken because of the CRC check, and it detects it.



AAL type 5 can efficiently offer the voice and the image at a changeable speed in service class B of AAL to a high-ranking layer compared with AAL type 3.

These sentences are wrong.
- AAL type 5 is defined as an ATM adaptation layer to provide the voice at a changeable speed of service class B and the service of the image etc.
- ↑ Moreover, this explanation is unknown. 。。

- Because AAL type 5 is not connection OR connectionless "Class B" in class D because it is type VBR and "Class D", these sentences might be mistakes.



Well, how?The bytalk, I have the memory of the examination of the problem of this ATM in the document of the Cisco system well considerably and rolling it up. Because information is obtained on the site etc. where the qualification acquisition of the reference book of CCNP or Cisco was made a subject, I think it is good when looking over once when it is not good though it is not thought that the technical book of the ATM system is found to be an almost good. Then, around here today

Even if a net synchronous method is said

Well, there is considerably a person who googles to analyze the person whom this blog inspected by the key word 【 telecommunication chief engineer reference book 】 though 20 days have passed since the study of the chief telecommunications engineer today, and this blog were established. Is all "It is necessary to study on earth with what" evidences to worry?This..blog..past..several times..write..think..this..qualification..reference book..exist..enough..test range..narrow..past..ask..get tired..the..inside..doubt..matter..good at..field..enumerate..correspond..technical book..buy..think.Then, today's material is [kochira] ↓.



- Net synchronous method in digital data exchange network



The variable frequency oscillator is prepared in each bureau in the net, and the method to control the oscillatory frequency of the bureau based on the phase lag of the clock of another bureau and the clock of the bureau is called mutual synchronous methods.


These sentences are correct.
- The variable frequency oscillator is prepared in each bureau in the net mutual synchronization =, and the oscillatory frequency of the bureau is controlled based on the phase lag of the clock of another bureau and the clock of the bureau.



The method to match the frequency of the general situation in the net by preparing one main oscillator in the master station (master bureau), and distributing the clock of the master station is called a subordination synchronous method.

These sentences are correct.
- Method to match frequency of general situation in net by preparing one main oscillator in slave synchronization = master station, and distributing clock of master station



A subordination synchronous method is divided into a strong connection type and a weak connection type depending on the action method of the master station when the disturbance and the breakdown occur in the clock distribution.

These sentences are wrong.
- A subordination synchronous method is divided into a strong connection type and a weak connection type depending on the action method of the tributary station in preparation for time when the disturbance and the breakdown occurred in the clock distribution.
- The breakdown influences a subordination synchronous method the disturbance of the transmission line.
- Make noise because it disturbance = is confused. Moreover, disturb the peace and order. Disturbance.
- Then, do not undertake all influences when the disturbance and the breakdown occur because everyone follows the master station.



The control over between bureaux is unnecessary though the oscillator with high accuracy like the cesium oscillator is demanded as for independence and synchronous a method.

These sentences are correct.
- Naturally, "Control over between bureaux" might be unnecessary because it becomes independent.



Today's material was a problem of the synchro system for the digital data exchange network. The net synchronization might be able technological used by the multiplexer etc. to say nothing of the switchboard to correspond considerably even if there is no knowledge of the district if the meaning of the word is often considered though comes out "Mutual", "Subordination", "Independence" or various methods. Then, around here today

2010/09/14

It is a problem of H.323.

Well, let's study the chief telecommunications engineer today. H.323 will really neatly feel a detailed protocol name for today's material in H.323 calmly reading the problem because there are a lot of confusing problems. whether to say regret to the remembranceThen, today's material is [kore] ↓↓.



- System that achieves communication by protocol of H.323



The H.323 terminal is a device that the user uses to do a real-time voice transmission, the image transmission, and the data communication.

These sentences are correct.
- Woo
As for "XXX terminal", isn't any protocol so for the user to use?



The H.323 gateway has the voice and the transducer function of the form of the transmission of information on the image needed to communicate between the H.323 terminal and the terminal of an existing line switching network like the telephone network etc.

These sentences are correct.
- The voice and the transducer function of the form of the transmission of information on the image are done, and the gateway is needed to communicate between terminals of an existing line switching network like the telephone network etc.



The H.323 gatekeeper has the communication mode control function etc. to secure the quality of the function and the communication that converts caller's telephone number etc. into Internet Protocol address.

These sentences are wrong.
- The gatekeeper manages caller's telephone number and the relation with Internet Protocol address, etc.It doesn't have the communication mode control function.
- The gatekeeper doesn't work to make a mistake .."Communication mode control function" in the latter half.. ..the part.. though it is correct around of "The telephone number is converted into Internet Protocol address" for forequarters of sentences ..so...



H.323MCU has a broadcast function etc. necessary to achieve the multi point communication (communication done with three terminals or more).

These sentences are correct.
- MCU communicates a multi point.


Well, how?Sentences of "Mistake" put there is no confidence for a moment, and "Here might be a mistake" might be a correct answer of the search for saying though it is considerably confusing because the problem of this hand does the writing of nasty sentences the stern can be very removed by the pronunciation. Then, around here today

2010/09/13

I will aim at the chief telecommunications engineer's qualification acquisition.

Well, I think that have the problem of the network system seen after a long time today. The problem of such a network system and the protocol system increases in recent years, too and the person who has challenged a technical engineer might grapple easily with chief telecommunications engineer's problem up to now. Then, today's material is [kochira] ↓.



- Function of router etc.



The function to judge right or wrong of the street of the packet is provided for one thing in each port number of the protocol in the transport layer, and the access from the outside by a specific protocol of the FTP etc. can restrict no permission etc. of the filtering function of the router.

These sentences are correct.
- It is a description of "Access list".



In the static routing method that is one of the setting methods of the routing table of the router, information is automatically comparatively converted between routers at a long interval time day and generally every month, etc. and the routing table is renewed.

These sentences are wrong.
- In the dynamic routing method that is one of the methods of setting the routing table of the router, information is automatically comparatively exchanged between routers at a long interval time generally day or every month, etc. and the routing table is renewed.
- The update doesn't do the routing table to the static routing by the automatic operation.



In RIP2(RIP Vervion2) that is one of the routing protocols of the dynamic routing method, using it from no function of the transmission of subnet mask information on the network composed of a variable-length subnet is unsuitable.

These sentences are wrong.
- In RIP2, the field of message formats not used is used, and the field of the route tag, the subnet mask, and the next hop is increased. Moreover, the IP multicast became available because of the load reduction of the network, too. Therefore, the function to transmit subnet mask information exists.
- When it is RIPv1, subnet information be able to be done certainly and come to do RIPv2 though it is incommunicable.



Three layer switches that are composed of the hardware subject because the performance that the router possesses is becoming a bottleneck on the network and work at high speed are developed, and the high-speed packet forwarding technologies of the store and the forward method, etc. are used.

These sentences are wrong.
- These sentences are explanations of cutting the through method. There is a merit that the priority control and error correction can be done instead of lacking at high speed (real time) because the transmission delay is generated unlike the circuit switching method when the store and the forward method (stored and forward switching system) are introduced.
- Neither the store nor the forward are so early. (Accumulate the packet and priority control and because it is done that the error is corrected. )

- As such, a free fragmentation is early (Because only the header part is confirmed).
- Cut and the through is the earliest (Because the packet is forwarded without confirming it).



Well, how?Sleeping then around here today though it is thought that it was a comparatively gentle problem if it is not good at problem of such a genre ..might take the study of a technical engineer and CCNA/CCIP for a moment by you..

It exchanges it today.

Does the chief telecommunications engineer's study make progress?Excellent study is necessary for passing of the chief telecommunications engineer of the transmission exchange and it just prays that be able it to sleep, and to become your post even a little this blog sincerely. Then, today's material is [kochira] ↓.



- Call processing program of digital switchboard for telephone



Call processing program is divided roughly into internal processing and the output processing at the input process. As for these processing, the operation order is controlled by the maintenance operation program, and high processing of the emergency degree interrupts low processing and is executed.

These sentences are wrong.
- As for these processing, the operation order is controlled by a central controller, and high processing of the emergency degree interrupts low processing and is executed.
- ..floatage.. ?As for "Maintenance operation program" [n] and in sentences, is the part good for "Central processing unit" if it mends?
- A central controller moves at the base level when all work at the clock level ends and is processing work. The result is brought together on the way of work when the constant period passes before work at the base level ends and the work that interrupts at the base level at the next cycle is drawn out after it interrupts, and it works at the clock level and it restarts.
- Is there such sentences, too and "Maintenance operation program" →"Central processing unit. " in sentences perhaps?。。



It is caught as input information, and internal processing begins if the state of the clock is observed, and there is a change at the input process.

These sentences are correct.
- It is assumed to be input information if the state of the local loops or the line like the call out, the response, cutting, and the dial pulse, etc. is observed, and there is a change and catching the internal processing begins at the input process.
- "State of the clock" is not observed and "State of the subscriber or the line" is observed.
- 。。。Are not you the no use of observing the clock it?



Internal processing analyzes input information, does necessary processing, and the output processing drives a telephone call road system device based on the result. A series of processing that selects the trunk and the route in internal processing is called a token.

These sentences are wrong.
- A series of work to select the trunk and the route in internal processing is called routing. It is correct in the first halfs of sentences.
- It is not a token and routing.



The transition condition between these states is described and the one having provided for piece processing function is called a state transition chart though it can be thought that the process from "Start of call" of one "Call" to "End of call" is the transition between two or more states.

These sentences are correct.
- The one that the transition condition between state transition chart = states is described and regulations of piece processing function
- The process from "Start of Call" of one "Call" to "End of Call" is a transition between two or more steady states.

It is possible to provide for "Call processing program" by the state transition chart to have recorded the transition condition between these states.



Well, often note successfully caught to hanging if there are a lot of problems sleeping around here excellent nasty the problem of the call processing program this time and the flow of the term and processing is not remembered neatly. Then, around here today

2010/09/10

It is a chief telecommunications engineer today.

The chief telecommunications engineer's of today study also puts "Exchange" to the subject. It publishes by two titles though it does because there is no time for a moment today at a smart trot. Then, the materials of eyes are [kochira] ↓ of one.


- Composition of switch of time of digital switchboard for telephone




The time switch is a device used for the speech path, and it is composed of the telephone call memory, the control memory, and the counter circuit.

These sentences are correct.
- It is composed of the telephone call memory, the control memory, and the time switch = circuit of the counter.



The telephone call memory is a memory that stores tonal information etc. that correspond to the multiplicity of the highway encoded digitally.

These sentences are correct.
- Memory that stores tonal information etc. that correspond to multiplicity of telephone call memory = highway encoded digitally



The control memory is a specified memory.

These sentences are correct.
- It is a specified memory. read



The counter circuit is a circuit to read sequentially or to write tonal information etc. encoded digitally in the control memory.

These sentences are wrong.
- The counter circuit is a circuit to read sequentially or to write tonal information etc. encoded digitally in the telephone call memory.
- It is not "Control memory", and "Telephone call memory" answers correctly.



Well, how?It remembers because it colors in will the point of each circuit the part of the deficit of a right cell. Then, today's the second material is [kochira] ↓.

- Multiprocessor control method of digital switchboard for telephone



In a function distributed control method, two or more processors are processing it respectively. To execute one exchange processing, the sending and receiving of information between these processors is necessary, and the sending and receiving of this concession is called an inter-processor communication.

These sentences are correct.
- Sending and receiving of information exchanged between processors to execute inter-processor communication = one exchange processing



In the inter-processor communication, it is possible to meet until it becomes possible to communicate the reception side processor because the state of each processor function is uniformly managed by the meeting control operation, and it accumulates communication information from the transmission side processor in the buffer memory once.

These sentences are correct.
- It meets until it becomes possible to communicate the reception side processor because the state of meeting function = each processor function is uniformly managed, and it accumulates communication information from the transmission side processor in the buffer memory once.



In the inter-processor communication, the bus can be prevented from competing according to the priority level provided beforehand when use rights of the bus between processors are uniformly managed by the rival control function of the bus, and there is a use demand of the bus.

These sentences are correct.
- The bus is prevented from competing according to the priority level provided beforehand when use rights of the bus between rival control function = processors of the bus are uniformly managed, and there is a use demand of the bus.



Yes, a problem here was a problem of the processor control method. Is there what worries so much if do not limit to the switchboard, and well versed in the equipment that uses "Processor"?I think that such a problem is brought up even if a technical engineer is studied. Then, it is necessary to work hard study of you and the chief telecommunications engineers. Around here today

2010/09/08

Control scheme in digital switchboard for telephone

Today's chief telecommunications engineer's material is "Switchboard. "Isn't the part of 【 exchange 】 as still important as that of taking side of "Transmission exchange" with the chief transmission and switching engineer?It thinks. "To begin with, what is the switchboard?" do not roughly understand even by the person even as for the person not involved in the switchboard though the problem of hitting the category of "Control scheme" in the problem of the exchange today if sentences are calmly read in case of the problem today?Then, today's material seen once is [kochira] ↓↓.



- Control scheme in digital switchboard for telephone



The control scheme to which all the exchange processing is done with one processor is called a centralized control method, and the control scheme to which the exchange processing is done with two or more processors according to each function or the load is called a distributed control method.

These sentences are correct.
- Centralized control method = Control scheme to which all exchange processing is done with one processor
- Control scheme to which exchange processing is done with two or more processors according to each function or distributed control method = load



In the centralized control method, the system processing performance depends on the ability of the processor. Moreover, two or more processors make troubleshooting/restart process complex from the method to distribute processing according to a different function.

These sentences are wrong.
- Certainly, troubleshooting/restart process will become simple because it is good when only a single processor is seen though might depend on the ability of the processor for the processing performance in the centralized control method.



A function distributed control method to allot the identical function with two or more processors can do large-scale processing by comparatively using two or more processors with small processing performance.

These sentences are wrong.
- "The identical function is allotted with two or more processors" might not be a function distributed control method and be a load-balancing control method.



How?Is Japanese calmly read even if it doesn't know "The technology" somehow and can it not answer correctly if it solves it?However, it is necessary to catch calmly often reading the problem because the expression of the problem is nasty. Then, let's see the problem of the switch system of another one today. This material is [kochira] ↓↓.



The time switch is each time slot and a switch that does the exchange connection between highways while arrange the timesharing gate between the insertion highway and ..putting out.. highway, high-speed this timesharing gate, and multiplexed by opening and shutting.

These sentences are wrong.
- 「It is a switch that replaces information by using the gate element that operates at high speed between high ways, and it is called the high way switch. The space switch is composed of the control memory that controls the opening and shutting of the gate of a lattice gate circuit and each time slot. 」

- "Space switch" answers "Time switch" of sentences of the problem correctly.



If the multiplicity of the highway that goes in and out is assumed to be n, the time switch functions as a lattice of a complete group where internal congestion doesn't exist, and can be shown with the space division type switch of n×n.

These sentences are correct.
- I will memorize these sentences round ・・・.



The space switch is a replaced switch in an arbitrary time slot on the highway. put out the slot of time on the insertion highway

These sentences are wrong.
- Because it is "Time slot" to replace the time slot, the time switch though it neatly examines and it doesn't exist.



The control memory of the space switch of each insertion highway has been installed.

These sentences are wrong.
- The space switch is a switch that replaces information by using the gate element that operates at high speed between high ways, and it is called the high way switch. The space switch is composed of the control memory that controls the opening and shutting of the gate of a lattice gate circuit and each time slot.
- I think that it is a mistake of "Gate circuit and each time slot .."Each insertion highway" of the problem sentence.." ..holding perhaps...



Well. Then, it was a problem of "Time switch" and "Space switch" though it was this problem. I think that you should see the reference book of an installation technician who is older to count on chief telecommunications engineer's reference book and problem collection perhaps when the problem around here will be studied in detail and study though a big thing cannot be said because I am not considerably good at the problem of this "Time switch" and "Space switch". Installation technician's reference book is considerably kind and, anyway, sleep ・・・ Then, around here today

2010/09/07

It is an outline of the ATM.

Well, I think that I do the problem of the ATM today. "Outline of the ATM" and the part that is only announcing and should suppressed by studying the ATM are published though it is thought that it only has to be able to read easily because this problem is "Fill-in-the-blank question". It first has in mind and it puts around here when not good at problem of the ATM. Then, today's material is [kochira] ↓↓.



- Outline of ATM



The cell used by the ATM is composed of 【53 bytes 】 that adds the header that contains routing information etc. by user information on the voice, the image, and data, etc.
- The ATM cell is composed of 【53 bytes 】 adding the header to user information.



In each cell header of the ATM, 【VCI】 that identifies a virtual channel as a connection identifier necessary to send it to the address until sending it and a virtual passing are identified. There is VPI, and the cell is turned to the address based on this information and the ATM switch is forwarded. At this time, to appear on the market, to seem to select [sen], and to advance, the ATM switch is said by the cell 【 self routing switch 】 about the address.

- 【VCI】 = virtual channel is identified.
- VPI = virtual passing is identified.
- 【 self routing switch 】 = seems to select the output line of the address by the cell and to advance.



There is a method of assuming a virtual channel to be to be remain set for a long term by the method and the contract, etc. to set to the setting method of a virtual channel only to communicate, and to liberate a virtual channel with the end of the communication. The virtual channel set by a latter method is called 【PVC】.
- Method of setting only SVC = to communicate, and liberating virtual channel with end of communication
- 【PVC】 Method of assuming virtual channel to be to be remain set for a long term by = contract etc.


Sleep. Outline really ?Because the part of the deficit becomes a really basic part to understand the ATM by right sentences, it neatly has in mind and it puts it. Coco is a liver of the ATM It was sentences explained almost bringing the ATM together. Then, because the outline was published a little more a little while ago, the problem of the ATM cell is done this time. Then, the following material is [kochira] ↓↓.



- Kind of ATM cell



To have continuously to spread the ATM cell over the payload of the SDH frame when the ATM cell is forwarded on the SDH network, an empty cell is inserted and forwarded between cells with effective information.

These sentences are correct.
- Because the payload is not integral multiples compared with 53 bytes of the size of the cell of the ATM, the last ATM cell on the frame might be accommodated across the following frame though the mapping is done by the payload of a virtual container of SDH as for the cell style to which the speed adjustment is done.
- An empty cell is inserted to put the speed of the ATM cell (speed of the valid cell) together at the transmission speed of SDH and the speed of the cell style adjusts.
- The ATM cell fully packs the package, inserts "Empty cell" in the opening part, and is doing the carrier of trailer (SDH) to SDH without the space. (padding)
- [Shitete], address VPI of the specialized form, and VCI become special like any one's neatly understanding "I am an empty cell" because it is not good this empty cell, too.



It is said by the ATM cell that doesn't contain the mistake in the header the valid cell excluding an empty cell.

These sentences are correct.
- The cell is . because it is errorless in the header excluding an empty cell (real cell) ..effective... 。。



It is said by the ATM cell to which the mistake is detected in the header, and it is corrected the invalid cell excluding an empty cell.

These sentences are wrong.
- This cell is up to . because it enacted the cell mistake ..effective.. though it might have been found to mistake it to the header excluding an empty cell (real cell). 。。・・・ It is a Japanese problem. 。。



When the cell mistake received in the error correction mode is detected, it mistakes it, and if the number of bits is one bit, it corrects, and if it is two bits or more, the cell is annulled.

These sentences are correct.
- I think that it is "FEC" that has come out before. Being able to do the error correction : only by one bit (annulment any more it) though FEC is possible the error detection and correction.



The difficulty so much doesn't write, and have it in mind, please often reading though "Oh…" seems to become because it fully packed the character in a narrow table for a moment. It often reads because the part that is the most basic the first half of today and this problem in the latter half understand the ATM. Then, around here today

2010/09/06

It is a kind of the SIP server.

Well, I think going of the problem of SIP today. This problem has the main proxy of server user agent server and RedirectServer・Register Server, etc. that construct SIP in the problem of the kind of the server that constructs the system of SIP. It is this problem to divide the proxy server from the viewpoint of the state management especially that again in detail. Then, today's problem is [kochira] ↓↓.


- SIP Server

The server that has the function to rewrite the requested address from the client at another address is called a proxy server.

These sentences are wrong.
- Isn't it not neither a proxy server because it rewrites it at another address nor RedirectServer?
- Change the input origin and output destinations of redirect = program to the one different from usually.
- In the meaning of "Substitution proxy =", the request of the client is relaid to the server corresponding to each service as a representation of the client.



It is classified from the viewpoint of the state management of the transaction into two, and the state of the transaction is not managed among these, and the proxy server only of the relay of the message is said by the proxy server StatelessServer.

These sentences are correct.
- The state of StatelessServer = transaction is not managed.
- The state of state full server = transaction is managed.


The server that relays the message to the server that provides service is called RedirectServer according to the request from the client.

These sentences are wrong.
- Isn't it not neither RedirectServer because the message is relaid to the server that provides service nor a proxy server?
- Change the input origin and output destinations of redirect = program to the one different from usually.
- In the meaning of "Substitution proxy =", the request of the client is relaid to the server corresponding to each service as a representation of the client.




How?
Was it familiar for a moment to classify the proxy server into "Stateless" and "Full the state" though the part where proxy was reversely explained redirecting in sentences did not think worry so much to be Well it was to be studied the composition of SIP?
The document of RFC of Stateless and a full state for a moment with solves in CocoState full proxy/ Logical entity that maintains transaction state machine of client and server (Define it with RFC3261) while processing the Stateful Proxy request. Alias transaction state full proxy. Refer to section 16 of RFC3261 for detailed operation of state full proxy. (transaction)State full proxy is different from call state full proxy. StatelessProxy/ Logical entity that doesn't maintain transaction state machine of client and server (Define it with RFC3261) when the Stateless Proxy request is processed. StatelessProxy forwards all received requests to the down stream, and all the received responses are forwarded to the improvement stream. I was going to quote the document of this from "Soft reception desk"'s SIP glossary. Around here desire and today when serving as a reference when there is a term that doesn't understand because the term is explained as http://www.softfront.co.jp/tech/whatsSIP/sip_glossary/sip_glossary.html is very detailed

2010/09/05

Time to forget the telecommunications technology is important too.

It parted from chief telecommunications engineer's topic during a day and the time of meditation decided to be worked out today.
It is real pleasure that can obtain the time that indulges to the desire by parting from the topic related to the telecommunication technology of every day on holiday.


What is the ATM?
What is PBX?
What is SIP?
What is the exchange?
Let's forget those technologies today by all means.


I enjoy the chat between families because it listens to favorite music, and it sees a movie that seems to be interesting・・・

Will you occasionally think that there may be such a day by you?

Working out such time becomes very difficult when usually engaged in work related to telecommunication.
The sense where time flows slowly is forgotten.

I think that I spend slow time today.

Then, you also must spend good time.

Digital switchboard for telephone.

I think that I go with the switchboard today though the material of "Switchboard system" continues recently. Well, this material is not judgment [surutteyatsu], and a fill-in-the-blank question as for the corrections of usual sentences. From from among choices Part of 【XXX】 originally becomes hole becoming empty, and to doing word choice and ..[] that buries hole.. problem of typeWell, if a right memo can be read after left sentences are comfortably read, it is thought ・・・・ therefore. Then, today's material is ↓↓.



- Digital switchboard for telephone


A digital switchboard for the telephone should maintain high reliability for a long time, and provide steady service continuously.
- Well, the switchboard is an expensive shopping and it doesn't become work if use for a long term, and not dependable.




In a digital switchboard for the telephone, processing (breakdown processing) that gives the breakdown measures to hardware and each software, detects the state promptly in abnormal circumstances, and does again normally has been achieved.
- The breakdown measures are given to each hardware software.




As for the breakdown processing, it is demanded that it is necessary to deal with all the system malfunctions effectively, it is necessary to process 【 in short course 】 extremely, and the incompleteness of the breakdown processing be concise, certain processing [houhou] because it becomes a fatal defect of the system.
- It is necessary to deal with the point and all the system malfunctions of the breakdown processing effectively. - It is necessary to process 【 in short course 】 extremely. - The incompleteness of the breakdown processing becomes a fatal defect of the system. - It is demanded that it be concise, certain processing [houhou].



Abnormality of the common control unit such as processors installs an abnormal detecting function in hardware as one of the failure detection techniques with hardware because the influence that it has on the system is large, and there is a method of starting the breakdown processing program stored in a fixed house number with 【 interrupt 】 circuit when abnormally detecting it.
- When * abnormality with a large influence that it has on the system is detected, abnormality of the common control unit such as processors starts the breakdown processing program stored in a fixed house number with 【 interrupt 】 circuit.



Moreover, there is a method of observing whether to fall in check on 【It is periodic 】, and 【 infinite loop 】(Processing circulates to the same program, and the control is not transferred to another program) the control of the clock level and the base level as one of the fault detections with software.
- 【It is periodic 】 ..control of the clock level and the base level.. is checked.
- 【 infinite loop 】 Processing circulates to = same program, and the control is not transferred to another program.



・・・It is [maa;konna] [kanji]. Left sentences take notes of the desire of one only of simple question and division in the cell by each [wo] punctuation in the past, and no "Point" to it it for right sentences should. Does a person not good only have to be able to help the remembrance of the movement of the switchboard even a little?Then, around here today

2010/09/04

Topic of call processing of PBX.

Yes, I think that the material of the study of the chief telecommunications engineer goes by the exchange today. Which program is which problem of judging whether to call and to do [no] processing though today's material is a call processing program of the switchboard. Then, today's material is [kochira] ↓↓.



- Outline of call processing program of digital switchboard for telephone


The call processing program calls and is [niha] and becomes empty, is in the call while talking over the telephone while receiving the dial figure this steady state, and has achieved the exchange connection operation by observing, analyzing the processing demand in these states, and doing processing necessary for the following state transition.

These sentences are correct.
- It ..calling.. ..[niha].. becomes empty, and this steady state exists while talking over the telephone while receiving the dial figure the call inside.
- The exchange connection operation is achieved by observing, analyzing the processing demand, and doing processing necessary for the following state transition.



An internal processing program is composed of the program etc. that detect the call out, the response, the local loops such as cutting or the change in the relay line.

These sentences are wrong.
- An internal processing program: It is composed of the program etc. that translate the program dial figure to which the connection status is decided based on the processing demand detected by the input process program.
- ・・・ Internal processing is opposite to the output processing.



The output processing program possesses the function to decide the connection status based on the processing demand detected by the input process program, and is composed of the program etc. that translate the dial figure.

These sentences are wrong.
- The output processing program: It is composed of the program etc. that detect the program, the call out that drives a telephone call road system device etc. , the response, the local loops such as cutting or the change in the relay line.
- ・・・ Internal processing is opposite to the output processing.



Well, how?In short, the explanation of "Internal processing program" in the problem sentences and "Output processing program" was only opposite to sentences of the mistake apart from correct sentences. Roughly, the division really composed of the program of "Dial figure translation" like the input process though it says is not in the output processing. 。。Then, around here today.

2010/09/03

BORSCHT was heard after a long time.

I think that today's chief telecommunications engineer's examination grind goes by the material of the exchange. Well, it somewhat thinks the step improvement after installation technician's qualification is acquired to chief telecommunications engineer's qualification to be a problem of being easy to work though there is a material [ttetottsukiyasui] image of "Exchange" because it is related to the business that I am involved in the switchboard. Then, today's material is [kochira] ↓↓.



- About the BORSCHT function of a digital switchboard for the telephone in the subscriber circuit



“B" of the BORSCHT function is abbreviation of Battery feed, and the function to supply the direct current needed when the dial pulse of the supply of the telephone call current is received another.

These sentences are correct.
- B's of BORSCHT is none.
- B supplies the current.



“S" of the BORSCHT function is abbreviation of Signaling, and the function to send the dial-tone, the ringing tone, and the engaged tone, etc.

These sentences are wrong.
- The function that the call out and the response, etc. from the subscriber can be observed by observing the current that flows to the L1 line and the L2 line with the direct current watch circuit is called S(loop watch) function in the subscriber circuit of S(loop watch) digital telephone switchboard. For instance, it is judged that the telephone is an off hook more than the threshold with the harmony of the current of the L1 line and the L2 line it.
- S thinks that no Signaling and Supervision. 。。



As for “C" of the BORSCHT function, is it a modulator and in the abbreviation of Coder, analog that consists of the recovery machine?It is a function that converts it digitally.

These sentences are wrong.
- The function to convert the analogue signal and the digital signal is called C function in the BORSCHT function in the subscriber circuit of C(analog to digital conversion) and the digital telephone switchboard.
- The function to convert the analogue signal and the digital signal is called A/D mutual conversion function. - Because "C" analogue signal/converts a digital signal with Codec, I think it is amusing in "Modulation and recovery" (The modulation is speaking the amplitude, the frequency, and the pulse).



Well, how?It is a problem of B, S, and C in that though today's material was BORSCHT of the exchange. I think the installation technician's examination to be a familiar problem in the chief telecommunications engineer's being taken an examination because BORSCHT was a requiring problem before. ・・・ Then around here today

2010/09/02

Today's topic is an ATM.

Well, chief telecommunications engineer's examination measures are done today. The problem related to the ATM thinks the subject of the transmission exchange and the plant management for you should make efforts and to finally exist because it is set questions at excellent frequency this time though it is a problem of a special field that tentatively handles a lot by this blog though it is a problem related to the ATM. Then, today's material is [kochira] ↓↓.



- ATM layer service

CBR is service that provides PCR(Perk Cell Rate), and guarantees CTD(Cell Transfer Delay), CDV(Cell Delay Variation), and the cell loss ratio.

These sentences are correct.
- CBR (Constant Bit Rate: constant bit rate): PCR (peak cell rate) is provided, and it is suitable for forwarding service and circuit switching services that guarantee CTD (cell transfer delay) and CDV and the cell loss ratio.



It doesn't make amends for the cell loss ratio though VBR is service to which SCR(Sustainable Cell Rate) and MBS(Maximum Burst Size) besides PCR are provided, and an image forwarding and an accumulative voice/data communication that uses the changeable speed sign assume it.
These sentences are wrong. - VBR (Variable Bit Rate: changeable speed service): SCR (average cell rate) besides PCR (peak cell rate) and MBS (maximum burst-length) are provided, and there are two categories of nrt-VBR for rt-VBR and the accumulation communication for serve real-time communication to which an image forwarding and an accumulative voice/data communication that uses the changeable speed sign are assumed and the cell loss ratio are guaranteed. - "The cell loss is secured. " though there are rough sentences.



It is a file transfer and service that is appropriate for the application of the transmission of the non-real-time data of E-mail etc. though not warranted the quality basically by UBR.

These sentences are correct.
- UBR (Unspecified Bit Rate): The file transfer and it serves that is appropriate for the application of the transmission of the non-real-time data of E-mail etc. though it doesn't warrant the quality basically.



ABR is to be adjusted the speed to install between MCR and PCR after MCR(Minimum Cell Rate) is secured by using RM cell (Resource Management Cell) to convenient service for the user who wants to use the bandwidth of becoming empty as much as possible.

These sentences are correct.
- From to install between MCR and PCR after MCR is guaranteed by using the transmission speed and RM (resource management) cell of the band that can be used, the speed is adjusted ABR (Available Bit Rate: bit rate that can be used): to convenient service for the user who wants to use the bandwidth of becoming empty as much as possible it.



How? It is confused and it divides, and refer the font color of the becoming it part in "Red", please the point the frequent occurrence of the term that looks like though it is a problem of the ATM (asynchronous transfer mode) though instigating it. An easy-to-use a little more in case of preserve it in the text editor or Excel duck because this blog is not thought to be terrible the table because right and left width of the article is narrow and to see easily. Then, around here today.

2010/09/01

It is large area EtherNet today.

Well, today's topic is large area EtherNet. It makes it in the communication relation of knowledge of Ethernet now, and [arukarakoso] [ki] of such a common sense problem is put and it makes it to a certain score source in engaged man though ..half common sense.. [bu]. Then, today's material is [kochira] ↓.




- Wide-area ethernet and IP-VPN



There is no use limitation in the protocol of layer 3 in the wide-area ethernet though the protocol that can be used is limited only to IP in IP-VPN.

These sentences are correct.
- Because IP-VPN uses IP as a protocol in the network layer as shown in the name, IPX or Appletalk is not choked.
- It doesn't dance ・・・.



IP-VPN uses the function of layer 3 as a mechanism of the data transfer while the wide-area ethernet uses the function of layer 2 as a mechanism of the data transfer.

These sentences are correct.
- Not speaking as shown in the above-mentioned.
- Layer 2 and IP-VPN use the function of layer 3 for the wide-area ethernet as a mechanism of the data transfer.



The main technology to achieve VPN on large area Ethernet includes the VLAN tagging technology and the Ethernet Over MPLS technology. Among these, the Ethernet Over MPLS technology is a technology that forwards the Ethernet frame on the MPLS network.

These sentences are correct.
-   Technology that sends and receives Ethernet packet on network constructed with MPLS. It is a mechanism that the MPLS network is passed adding the label of MPLS to the Ethernet packet.  There is an advantage that all the protocols used on Ethernet can be used because the packet of Ethernet can be sent and received directly between networks through EoMPLS though it is chiefly a protocol for the VPN construction as well as MPLS by the same sense as past LAN. Moreover, because the MPLS network for TCP/IP can be misappropriated as it is, the equipment load of the provider is comparatively suppressed.
- Well, the Japanese syllabary as shown in the name.



How?Even if the large area is said, usual EtherNet and the idea are the same as the idea. Making a mistake perhaps if the reference model of OSI is calmly judged is a problem of it not is. However, the problem of becoming such a score source when becoming a real thing of the examination also lacks and drops calm ・・・ It takes care. Then, ↓ by another question.




- Basic technology of Ethernet



In the CSMA/CD method that is the access control method, even if one node breaks down, it doesn't influence the communication between other nodes.

These sentences are correct.
- It reels, one node breaks because it might become the topology of , star type, the way exists, and there is no influence.



In general, it is called a broadcast roughhouse that it becomes impossible to generate an infinite loop by the broadcast packet on the network, and to communicate the user.

These sentences are correct.
- You may feel it for infinite loop = broadcast roughhouse on the network.



Only the symmetry of the auto negotiation function of 1000BASE-X is the between the same methods (SX and LX, etc.), and the auto negotiation function doesn't operate between different methods (SX and LX, etc.).

These sentences are correct.
- If it is not the same method, an auto negotiation of 1000BASE-X is not good.



A transparent bridge does the relay processing of the communication that shuts in one segment because it doesn't judge whether to do the relay processing between each segment.

These sentences are wrong.
- The relay processing cannot be done about the communication that shuts in one segment.
- The segment of an access control method the transparent bridge = same ties. For instance, it is easy to understand neither these problem sentences of * somehow nor explanations Ethernet, Ethernet, FDDI, and FDDI it.



Thank you it is a strange explanation. 。。As for sentences wrong apart from correct sentences, a transparent bridge is "Bridge. " to the end. Two segments' tying doesn't forget the thing in the work of the bridge. Then, around here today

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