All Optical Network

The so-called all optical network, refers to the signal only when in and out of the network to make the electricity/light and light/electric transformation, and in the network transmission and exchange with the process always exists in the form of light. Because in the transmission process without electricity process, so PDH, SDH, ATM, etc. Various kinds of transmission way, improve all can use the network resource utilization.

All optical network related technologies

All optical network of related techniques include a full optical switching, light crossing connection, all optical relay and recovery with/to reuse, etc.

All optical network technology promises good foreground is very simple: data will be the faster speed transmission, because the data with only light form coded.

"Only" is a key word. At present, the optical network equipment receive light pulses from cable, convert it to electrical signal processing, then will signal reduction for light for transmission. Even if the processing time is zero, this kind of conversion will increase delay.

Light technology advocates say, eliminate photoelectric conversion will make the data rate reached WanYiWei level. A the often-quoted said fiber has 25 trillion refer to 75 WanYiWei/SEC capacity, and the theory of data and the data rate on the copper wire BaiWanWei program usually compare, and demonstrate its advantage.

But this argument is not involved in all optical networks two basic requirements: routing and buffer.

Now in all optical networks without routing protocols that kind of stuff. At present, the optical network equipment running in point-to-point or the loop topology structure. Point-to-point refers to A light pulse either equipment, A transmitted to equipment B, or not transfer. If cable interruptions, point-to-point method was not backup connection. Like the automatic protection SONET exchange this loop technology provides the slightly better redundancy: once cable interruptions, loop can go round it.

And any more complex topology structure need routing technology.

Some light network technology advocates say, routing decision belongs to the edge of the optical network. Indeed, as long as all optical network is small and simple. If switch manufacturer truly want to increase sales, they need in their devices provide more intelligent.

All optical network is another major obstacle to find a buffer light way. Not a light equipment can like electronic equipment buffer as slow packets light propagation speed or storage light.

Unable to buffer the light makes all optical network equipment in any existing congestion environment not having practicability. Suppose there is a light network switch to the same destination, two hair the light pulse and to reach the equipment. This switch can't buffer light will only get rid of a pulse.

Unable to buffer light maybe things will change. But also, by one estimate, will take 10 to 50 years, the study will put into application.

other

Optical network equipment has played an important role. But, to some of the key challenges to overcome before industry, all optical networks is still a kind of pure thought and suspicious sales promotion.