The Realization Process Of The Draft-anavi-tdmoip-03

The price of IP operation has been lower than traditional TDM,so more and more people pay researching key point at how to IP transmitting technical。Now the operation based circulation is all carried by TDM network。Many movie business confront the question how to use uniform communication base equipment to synthesize many operations。Even if many data operations is based IP network now,In order to guarantee evolving toward next grouping internet smoothly,communication base equipment must be able to uphold traditional TDM and other operations based circulation。One the most common project is set up transmitting grouping of the circulation in advance。But to network ,the main payload is IP operation。It is neither the most efficient nor upgrade simply。Another evolving project is transmitting operation based in circulation on the grouping network,Voice over IP is to utilize this project technical。Now,to the realization of VoIP,there are some limitations,the most key question is quality of service and the limitation of signal upholding。Because the quantity additional operations sustained by telephone network in present are realized through signal transmitting,but VoIP technical can't uphold the exchange of signal well,this become the obstacle of popularizing VoIP technical。There is a kind of technical which can transmit all operations based circulation operation—— TDM over IP。The technical can both uphold the operation which type is TDM (T1/E1~T3/E3) and uphold other traditional type operations。QOS and voice quality correspond to what the network based circulation offer in present,moreover, all signals characteristic will be sustained。We offer the normal format of the draft-anavi-tdmoip-03,the data format correspond to International Communication standard。We research the context of this standard,ascertain the location in the H521TDMA board of the LG123 ASIC , analyze and describe the function that LG123 can offer。LG123 logic need finish adapting from ATM cell to IP/UDP package on the H521TDMA board,accordingly realizing adapting of TDM operation on the IP internet。LG123 correspond to draft-anavi-tdmoip-03,uphold IP protocol,VLAN80801.Q protocol,moreover uphold EthernetⅡ encapsulation,realizing transmitting the TDM operation transparently on the RPR loop network。We process the TDMoIP operations in the direction of Egress and in the direction of Ingress。The process adopt DFD means to analyze and describe the needing function,and adopt false code to realize the function what DFD need first,then using Verilog language to realize function according function needing analyze。In the direction of Egress disposing MAC layer first,bellwether code peel off ,CRC check,length check,memory slowly,MAC filtrate。Then disposing UDP/IP layer,IP check,UDP header check, distilling circuit bundle number。Finally,disposing TDMoIP layer: Control Word analyzing,queuing based in E1 port (eight ),flux control,slicing up,The process of data disposing in the direction of Ingress is opposition。In the UDP layer of the direction of Egress,we adopt token bucket to control runoff。(register :Egress Port Bucket Level is collocated by user,the range of fetching value:1~32,lack value:16,)and bucket rate(register:Egress Port x Bucket Rate K)can be allocated,only when token bucket have token did it can transmit token,transmitting a ATM cell each time( every token denote can transmitting a ATM cell)。among the ports,we adopt RR(Round Robin)attempering fairly ——the rule of cycling in turn,namely checking every E1 port in turn。Only when there is both queue to need exporting and there is token falling,did we can deliver the queue out of queue。We prevent the data overflowing or let the bucket empty。We encapsulate VLAN-tag of 4 bytes in the Ethernet Header beyond the draft-anavi-tdmoip-03 。To the package which require real time characteristic strictly,host compute mention that priority is high in advance ,in additional 3 bit of MAC frame header has refer to it。In t...