DESC:DESCRIPTION

[0001] Field of the Disclosure

[0002] In passive optical network PON system, an important concept in OLT system is GEM.

[0003] GEM is a way to encapsulate data on GPON.

[0004] The service virtual channel between OLT and ONT identified by GEM port is the channel carrying the service flow. Each PON port has the same fixed number of GEM ports with different port numbers to provide services for different ONUs. With the development of technology, there are more and more high-speed ports in the interfaces of switches in OLT, so the ports providing PON services need to be multiplexed to match the high-speed interfaces to make the best use of them. For example, the standard port rate of GPON is 2.5Ge, so four PON ports need to be multiplexed into a 10Ge switch port, which means 4:1 multiplexing of ports.

[0005] This design is a trend. Although the GEM port identification in a PON port is different, in the case of 4:1, the traffic flows of four ports will enter the same high-speed interface of the switch, and there will inevitably be traffic flows with the same GEM port identification. In this case, the switch cannot identify which PON port it comes from. However, the PON interface traffic passes through a 2-bit field that resides in the external (tunnel) TAG bit of the data packet, so a tag carrying GEM information will be played. But the two bits occupied by PON port identification are the lowest bits of CFI and PRI in VLAN. In this way, not all switches can identify and match. Kindly Refer Figure 1 which is on GPON Multiplexing Label

[0006] Considering the market segmentation of GPON, the market positioning and demand of OLT products are different. In the attitude of being responsible for customers, the adaptation modes of different switches are carefully studied. On the basis of ensuring the function of OLT, the invention completes the reuse of PON port identification and GEM port identification.

[0007] Note: The method of multiplexing PON port identification and GEM port identification is to shift the 2 of PON port identification to the 2 higher bits of GEM port identification, thus solving the problem that the number of matching rules is not enough when the switch identifies multiple VLAN:

[0008] But there will be the following shortcomings:
[0009] 1. The number of GEM ports supported by each PON port is reduced from 4096 to 1024;
[0010] 2. Under the condition of maintaining the light splitting ratio of 1:128, the number of GEM port identifiers supported by each ONU is reduced from 16 to 8.
[0011] 3. Through the analysis of the market, the decrease of GEM port identification specifications does not affect customer satisfaction in GPON market. Eight GEM ports fully meet the requirements of data, voice, video and monitoring on each ONU in the existing GPON market.

[0012] This patent proposes a solution that OLT supports different switches without reducing ONU data, voice, video and monitoring services as follows:
[0013] 1. PON port identification is shifted to the upper 2 bits of GEM port identification; That is to say, the GEM port was originally a 12-bit identifier, and now its top two bits, 12 and 11, are used to identify the PON port, which is equivalent to changing the GEM port identifier from the original 12 bits to 10 bits. Refer to Figure 2. Multiplex diagram of 2.PON port identification and GEM port identification.
[0014] 2. After receiving the uplink message, the switch only analyzes the data of the GEM port identification part, and does not need to care about the PRI and CFI parts in the highest 4 bits;
[0015] 3. The upper two bits of the 3.GEM port identification completely meet the identification of four PON ports: 00, 01, 10 and 11;

[0016 ] Through the above design, the port adaptation ability of OLT system can be greatly improved, and more switch ports can be saved to provide other functions.

[0017] The development of OLT also has a lot of room in selecting switch chips, and different OLT styles can be designed to meet different markets, which can also effectively reduce the cost of OLT manufacturers.

[0018] The design of the invention only involves the internal communication between the PON chip and the switch chip, and there is no external perception, thus ensuring the safe and smooth upgrade.

[0019] As shown in Figure 2,Multiplex diagram , the PON port identifier [2] occupies the upper 2 bits of the GEM port identifier [12], and the GEM port identifier has changed from [12] (see Figure 1) to [10]. Switches will have a unified solution to GEM+SVLAN, GEM+SVLAN+CVLAN and GEM+UNGTAG when analyzing traffic flows. The realization of this shift is that the PON system software creates corresponding GEM port identifiers for the two streams according to which PON port the uplink message comes from, that is to say, the GEM port identifiers of the streams received by the switch are already the combined identifiers.

[0020] Implementation description:
[0021] 1. According to the multiplexing mode as shown in Figure 3, (4:1 multiplexing diagram of 3.PON port and switch port.) the number and types of switch ports will be considered in the design of OLT system; (Invention 1, Maximize the port adaptation using PON chip and switch chip)
[0022] 2. According to the multiplexing mode as shown in Figure 3, the selection of switches is simple; (Invention 2, using the existing VLAN technology to realize the reuse of GEM and PON ports)
[0023] 3. Flexible market launch.

[0024] The key point is:
[0025] PON system software is assembled according to the port of the uplink message.
[0026] Switch configuration rules, analyze and record the corresponding GEM port identification, and peel off the GEM identification. Downlink needs to find the corresponding GEM port identifier according to the corresponding VLAN conversion rules, and then call it outside the SVLAN and send it to the PON chip to complete the service flow

[0027] Abbreviations and acronyms
[0028] 1. PON : Passive optical Network
[0029] 2. OLT : Optical Line Termination
[0030] 3. GEM : G-PON encapsulation Mode
[0031] 4. ONU : Optical Network line
[0032] 5. VLAN: virtual Local Area Network
[0033]6.XGPON: 10Gigabit-capable Passive Optical Network
[0034]7. XGSPON: 10Gigabit-capable Sync Passive optical network
,CLAIMS:What is claim is:

1. A method to Maximize the port adaptation using PON chip and switch chip.
2. the method of claim 1, wherein using the existing VLAN technology to realize the reuse of GEM and PON ports
3. the method of claim 2, wherein The variant scheme of the invention can be reused in the XGEM of XGPON and XGSPON, which provides a simple design scheme for the development of OTL in the future.