Routing can be divided into static and dynamic routing. The static route is manually maintained by the administrator; the dynamic route is automatically maintained by the routing protocol.
Necessary steps of routing algorithm: 1. Pass routing information to other routers; 2. Receive routing information from other routers; 3. Calculate the optimal path to each destination network based on the received routing information, and generate routing from it Selection table; 4. Respond in time according to the change of the network topology, adjust the route to generate a new routing table, and at the same time announce the topology change to other routers in the form of routing information.
Two main algorithms: Distance Vector Routing and Link-State Routing. It can be divided into distance vector (such as: RIP, IGRP, EIGRP), link state routing protocol (such as: OSPF, IS-IS).
The routing protocol is a mechanism for sharing routing information between routers. It allows routers to exchange and maintain their own routing tables. When a router's routing table changes for some reason, it needs to promptly notify other routers connected to this change to ensure the correct transmission of data. The routing protocol does not undertake the task of data transmission between end users on the network.
※Simply talk about the operating process of OSPF
①The router sends the HELLO message; ②Establishes the adjacency relationship; ③Forms the link state ④The SPF algorithm calculates the optimal path ⑤Forms the routing table
※The basic working principle of the OSPF routing protocol, the election process of DR and BDR, the role of the area and the transmission of LSA (Note: The other party has more detailed questions about OSPF related knowledge and should be focused on).
Features are: 1. Fast convergence speed; 2. Support classless routing table query, VLSM and super network technology; 3. Support multi-channel load balancing at equal cost; 4. High routing update delivery efficiency (regional, multicast update, DR/BDR); 5. Perform the most optimal route according to the link bandwidth (cost).
It is found that neighbors have established adjacency relations by sending HELLO messages, the same link state database is formed by flooding LSA, and the routing table is generated by using the SPF algorithm.
DR/BDR election: 1. DR/BDR exists -> no election; reaching the 2-way state Priority is not 0->eligibility; 3. BDR is selected first, then DR; 4. Using "priority" and "RouterID" for judgment .
1. By dividing the area, the router LSA DB can be reduced, and the overhead caused by CPU, memory, and LSA flooding can be reduced. 2. The TOP change can be limited to a single area to speed up convergence.
LSA1 and LSA2 are only transmitted in the originating area; LSA3 and LSA4 are transmitted by the ABR and transmitted in the OSPF domain; LSA5 is transmitted by the ASBR and transmitted in the OSPF AS; LSA7 is only transmitted in the NSSA.
※What are the advantages of OSPF? Why does OSPF converge faster than RIP?
Advantages: 1. Fast convergence speed; 2. Support classless routing table query, VLSM and super network technology; 3. Support multi-channel load balancing at equal costs; 4. High routing update delivery efficiency (regional, multicast update, DR /BDR); 5. Optimal route selection based on link bandwidth
Adopt area, multicast update, incremental update, 30 minutes retransmission of LSA
※What is the difference between RIP version 1 and version 2?
Answer: ①RIP-V1 is a classful routing protocol, RIP-V2 is a classless routing protocol ②RIP-V1 broadcast routing update, RIP-V2 multicast routing update ③RIP-V2 routing update carries more information than RIP-V1
※Describe RIP and OSPF, their differences and characteristics
The RIP protocol is a traditional routing protocol, suitable for relatively small networks, but the rapid development and rapid expansion of the current Internet network makes the RIP protocol unable to adapt to today's networks.
The OSPF protocol was developed when the Internet network expanded rapidly, and it overcomes many of the defects of the RIP protocol. RIP is a distance vector routing protocol; OSPF is a link state routing protocol.
RIP&OSPF management distances are: 120 and 110
1. A route of the RIP protocol has a limit of 15 hops (gateway or router). If a RIP network route spans more than 15 hops (router), it considers the network unreachable, while OSPF does not limit the number of crossing routers.
2. The OSPF protocol supports variable-length subnet masks (VLSM), but RIP does not. This makes RIP lack support for current IP addresses and the flexibility of variable-length subnet masks.
3. The RIP protocol is not aimed at the actual situation of the network but periodically broadcasts the routing table, which is a great waste of network bandwidth resources, especially for large-scale wide area networks. The routing broadcast update of the OSPF protocol only occurs when the routing status changes, and IP multicast is used to send link status update information, which saves bandwidth.
4. The RIP network is a flat network, and there is no layering of the network. OSPF has established a hierarchical concept in the network. In autonomous domains, network domains can be divided, so that routing broadcasts can be restricted to a certain range and the waste of link relay resources can be avoided.
5. OSPF uses an authorization mechanism when routing broadcasts to ensure network security.
The difference between the above two shows the characteristics of the OSPF protocol coming from behind. Its advanced nature and complexity make it adapt to today's increasingly large Internet network and become the main Internet routing protocol.
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How far(long) the transmitter cover?
The transmission range depends on many factors. The true distance is based on the antenna installing height , antenna gain, using environment like building and other obstructions , sensitivity of the receiver, antenna of the receiver . Installing antenna more high and using in the countryside , the distance will much more far.
EXAMPLE 5W FM Transmitter use in the city and hometown:
I have a USA customer use 5W fm transmitter with GP antenna in his hometown ,and he test it with a car, it cover 10km(6.21mile).
I test the 5W fm transmitter with GP antenna in my hometown ,it cover about 2km(1.24mile).
I test the 5W fm transmitter with GP antenna in Guangzhou city ,it cover about only 300meter(984ft).
Below are the approximate range of different power FM Transmitters. ( The range is diameter )
0.1W ~ 5W FM Transmitter ：100M ~1KM
5W ~15W FM Ttransmitter : 1KM ~ 3KM
15W ~ 80W FM Transmitter : 3KM ~10KM
80W ~500W FM Transmitter : 10KM ~30KM
500W ~1000W FM Transmitter : 30KM ~ 50KM
1KW ~ 2KW FM Transmitter : 50KM ~100KM
2KW ~5KW FM Transmitter : 100KM ~150KM
5KW ~10KW FM Transmitter : 150KM ~200KM
How to contact us for the transmitter?
Call me +8618078869184 OR
Email me [email protected]
1.How far you want to cover in diameter ?
2.How tall of you tower ?
3.Where are you from ?
And we will give you more professional advice.
About Us
FMUSER.ORG is a system integration company focusing on RF wireless transmission / studio video audio equipment / streaming and data processing .We are providing everything from advice and consultancy through rack integration to installation, commissioning and training.
We offer FM Transmitter, Analog TV Transmitter, Digital TV transmitter, VHF UHF Transmitter, Antennas, Coaxial Cable Connectors, STL, On Air Processing, Broadcast Products for the Studio, RF Signal Monitoring, RDS Encoders, Audio Processors and Remote Site Control Units, IPTV Products, Video / Audio Encoder / Decoder, designed to meet the needs of both large international broadcast networks and small private stations alike.
Our solution has FM Radio Station / Analog TV Station / Digital TV Station / Audio Video Studio Equipment / Studio Transmitter Link / Transmitter Telemetry System / Hotel TV System / IPTV Live Broadcasting / Streaming Live Broadcast / Video Conference / CATV Broadcasting system.
We are using advanced technology products for all the systems, because we know the high reliability and high performance are so important for the system and solution . At the same time we also have to make sure our products system with a very reasonable price.
We have customers of public and commercial broadcasters, telecom operators and regulation authorities , and we also offer solution and products to many hundreds of smaller, local and community broadcasters .
FMUSER.ORG has been exporting more than 15 years and have clients all over the world. With 13 years experience in this field ,we have a professional team to solve customer's all kinds of problems. We dedicated in supplying the extremely reasonable pricing of professional products & services. Contact email : [email protected]
Our Factory
We have modernization of the factory . You are welcome to visit our factory when you come to China.
At present , there are already 1095 customers around the world visited our Guangzhou Tianhe office . If you come to China , you are welcome to visit us .
At Fair
This is our participation in 2012 Global Sources Hong Kong Electronics Fair . Customers from all over the world finally have a chance to get together.
Where is Fmuser ?
You can search this numbers " 23.127460034623816,113.33224654197693 " in google map , then you can find our fmuser office .
FMUSER Guangzhou office is in Tianhe District which is the center of the Canton . Very near to the Canton Fair , guangzhou railway station, xiaobei road and dashatou , only need 10 minutes if take TAXI . Welcome friends around the world to visit and negotiate .
Contact: Sky Blue
Cellphone: +8618078869184
WhatsApp: +8618078869184
Wechat: +8618078869184
E-mail: [email protected]
QQ: 727926717
Skype: sky198710021
Address: No.305 Room HuiLan Building No.273 Huanpu Road Guangzhou China Zip:510620
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English: We accept all payments , such as PayPal, Credit Card, Western Union, Alipay, Money Bookers, T/T, LC, DP, DA, OA, Payoneer, If you have any question , please contact me [email protected] or WhatsApp +8618078869184
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Pay by Western Union to me :
First name/Given name: Yingfeng
Last name/Surname/ Family name: Zhang
Full name: Yingfeng Zhang
Country: China
City: Guangzhou
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T/T . Pay by T/T (wire transfer/ Telegraphic Transfer/ Bank Transfer)
First BANK INFORMATION (COMPANY ACCOUNT):
SWIFT BIC: BKCHHKHHXXX
Bank name: BANK OF CHINA (HONG KONG) LIMITED, HONG KONG
Bank Address: BANK OF CHINA TOWER, 1 GARDEN ROAD, CENTRAL, HONG KONG
BANK CODE: 012
Account Name : FMUSER INTERNATIONAL GROUP LIMITED
Account NO. : 012-676-2-007855-0
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Second BANK INFORMATION (COMPANY ACCOUNT):
Beneficiary: Fmuser International Group Inc
Account Number: 44050158090900000337
Beneficiary's Bank: China Construction Bank Guangdong Branch
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Address: NO.553 Tianhe Road, Guangzhou, Guangdong,Tianhe District, China
**Note: When you transfer money to our bank account, please DO NOT write anything in the remark area, otherwise we won't be able to receive the payment due to government policy on international trade business.
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* It will be sent in 1-2 working days when payment clear.
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* If the packages is below 2kg,we will be shipped via post airmail, it will take about 15-25days to your hand.
If the package is more than 2kg,we will ship via EMS , DHL , UPS, Fedex fast express delivery,it will take about 7~15days to your hand.
If the package more than 100kg , we will send via DHL or air freight. It will take about 3~7days to your hand.
All the packages are form China guangzhou.
* Package will be sent as a "gift" and declear as less as possible,buyer don't need to pay for "TAX".
* After ship, we will send you an E-mail and give you the tracking number.
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For Warranty .
Contact US--->>Return the item to us--->>Receive and send another replace .
Name: Liu xiaoxia
Address: 305Fang HuiLanGe HuangPuDaDaoXi 273Hao TianHeQu Guangzhou China.
ZIP:510620
Phone: +8618078869184
Please return to this address and write your paypal address,name,problem on note: |
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