CWDM vs DWDM ♦♦ Wavelength Division Multiplexing (WDM)
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♦♦ CWDM vs DWDM ♦♦
Wavelength Division Multiplexing (WDM) allows different data streams to be sent simultaneously over a single optical fiber network. The two key WDM technologies are Coarse Wavelength Division Multiplexing, CWDM and Dense Wavelength Division Multiplexing, DWDM.
Which solution is best suited to a given environment depends on the network and user requirements ? 💡 💡
Both technologies are independent of protocol, meaning that any mix of data, storage, voice or video can be used on the different wavelength channels. In fiber terms, the main difference between CWDM and DWDM technologies lies in how the transmission channels are spaced along the electromagnetic spectrum.
♦♦Coarse Wavelength Division Multiplexing - CWDM♦♦
CWDM supports up to 18 wavelength channels transmitted over a dark fiber at the same time. To achieve this, the different wavelengths of each channel are 20nm apart. Two wavelength regions are most commonly associated with CWDM, 1310nm and 1550nm. The 1550nm region is more popular because it has a lower loss in the fiber (meaning the signal can travel farther). CWDM technology offers a convenient and cost-efficient solution for shorter distances of up to 70 kilometers. For distances between 40 and 70 kilometers, CWDM tends to be limited to supporting eight channels due to a phenomenon called the water peak of the fiber.
♦♦Dense Wavelength Division Multiplexing-DWDM♦♦
DWDM supports up to 80 simultaneous wavelength channels, with each of the channels only 0.8nm apart. Unlike CWDM, DWDM connections can be amplified and can, therefore, be used for transmitting data much longer distances. The sweet spot for CWDM is up to 10 Gigabit Ethernet and 16G Fiber Channel. And it is quite unlikely capacities with increase beyond this in the future. DWDM however, is able to handle higher speed protocols up to 100Gbps per channel making it a more suitable technology for higher speed protocols. Traditionally CWDM components have been lower in cost making it more popular than DWDM. Now the price for both solutions is comparable. With higher speeds, more channel capacity, longer distances and passive networking, DWDM is the technology of choice for green field installations.
So sánh CWDM và DWDM
Công nghệ Wavelength Division Multiplexing (WDM) cho phép truyền nhiều luồng dữ liệu đồng thời trên một mạng cáp quang. Hai công nghệ WDM chính là Coarse Wavelength Division Multiplexing (CWDM) và Dense Wavelength Division Multiplexing (DWDM).
Sự khác biệt chính
Khoảng cách kênh: CWDM có khoảng cách kênh 20nm, trong khi DWDM chỉ có 0.8nm.
Số kênh: CWDM hỗ trợ tối đa 18 kênh, DWDM hỗ trợ tối đa 80 kênh.
Khoảng cách truyền: CWDM phù hợp cho khoảng cách ngắn (tối đa 70km), DWDM phù hợp cho khoảng cách dài hơn.
Tốc độ: CWDM phù hợp cho tốc độ tối đa 10Gbps, DWDM hỗ trợ tốc độ lên đến 100Gbps.
CWDM
Hỗ trợ tối đa 18 kênh.
Khoảng cách kênh 20nm.
Phù hợp cho khoảng cách ngắn (tối đa 70km).
Giá thành thấp hơn trước đây, hiện nay tương đương DWDM.
DWDM
Hỗ trợ tối đa 80 kênh.
Khoảng cách kênh 0.8nm.
Phù hợp cho khoảng cách dài hơn.
Hỗ trợ tốc độ cao hơn (lên đến 100Gbps).
Phù hợp cho mạng mới (green field installations).
Lựa chọn công nghệ
CWDM: Phù hợp cho mạng nhỏ, khoảng cách ngắn, tốc độ thấp.
DWDM: Phù hợp cho mạng lớn, khoảng cách dài, tốc độ cao.