Hello, everyone.
In this post, I would like to share with you the different between MAC transparent mode and Bit transparent mode in WDM.
1. Data Service Mapping Mode
Mapping Mode | Carried Client Service Type | Transparent Transmission Layer of Client Signals |
MAC(GFP-F) | 100GE | MAC |
BIT(GMP) | 100GE | PHY |
2. GFP-F mapping of 10GBASE-R (LAN PHY) payload only into OPU2
A payload information transparent mapping can be performed according to clause 17.4 of [ITU-T G.709] using the following process:
• Terminate (sink) the 64B/66B line code, preamble, SFD and IPG as per [IEEE 802.3].
• Apply GFP-F framing.
• Encode into an OPU2 according to clause 7.3 of [ITU-T G.709].
The mapping of generic framing procedure (GFP) frames is performed by aligning the byte structure of every GFP frame with the byte structure of the OPUk payload (see Figure 17-7). Since the GFP frames are of variable length (the mapping does not impose any restrictions on the maximum frame length), a frame may cross the OPUk frame boundary.
GFP frames arrive as a continuous bit stream with a capacity that is identical to the OPUk payload area, due to the insertion of Idle frames at the GFP encapsulation stage. The GFP frame stream is scrambled during encapsulation.
3. Bit transparent mapping of 10GBASE-R signal into OPU2e
This mapping has been moved to clause
17.2.4 of [ITU-T G.709]. With this mapping, the resulting OTU-like OTU2e signal must be clocked at a nominal bit rate of 11.0957 Gbit/s, as opposed to the standard OTU2 nominal bit rate of 10.709225316 Gbit/s.
Groups of 8 successive bits (not necessarily being a byte) of the CBR10G3 signal are bit-synchronously mapped into a data (D) byte of the OPU2e (see Figure 17-5). 64 fixed stuff (FS) bytes are added in columns 1905 to 1920.
NOTE – The NJO byte will always carry a stuff byte, the PJO byte will always carry a data (D) byte and the JC bytes will always carry the all-0's pattern.
4. Physical Layer Section Analysis
5. Transport Local Fault Information
6. The brief difference between the MAC transmission and BIT transmission
Transmission mode | BIT transmission mode | MAC transmission mode |
Transparent Transmission layer | Physical layer | Date link layer |
Clock transmission in physical layer | YES | NO |
Port link status can be transmitted | YES | NO |
PHYSICAL layer defines private protocol can be transmitted. | YES | NO |
That's all. Thank you!
