The hottest potn builds a new generation of bearer

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Potn builds a new generation of bearing network for multi-layer network optimization

potn realizes the functions of the previous PTN and OTN devices in one device, but if it is just a simple superposition of device functions, the improvement of network level, bearing efficiency, network protection and other aspects is not obvious, and multi-layer network optimization needs to be further carried out. The optimization of potn includes the optimization of forwarding plane, optical layer, mapping path, OAM and protection

optimized forwarding plane

the packet switching of PTN equipment does not have the ability of large particle ODUk scheduling. OTN equipment generally realizes ODUk scheduling through TDM circuit switching technology, but does not have the ability of packet switching. Potn requires the integration of PTN and OTN functions. It should have the switching capacity of both small particle packet services and large particle ODUk services. The potn equipment adopts the unified cell switching technology to realize the non blocking scheduling of services and the real integration of PTN and OTN at the switching level. The packet service and OTN sub wavelength service share the same switching matrix, and the proportion of packet and TDM service can be adjusted arbitrarily without changing the total switching capacity

If PTN and OTN are simply superimposed, they also face the problems of fiber hopping in a large number of devices, configuring multiple OTU boards, and increasing service delay. Therefore, the data forwarding surface also needs the further integration of PTN and OTN functions. The line side completes the unified bearing of packet services and OTN sub wavelength services through the hybrid line card. The PTN and OTN services on the customer side can be exchanged to the hybrid line card in any proportion. Therefore, the equipment also reduces a large number of OTU line cards, and reduces a large number of fiber hopping and service delay between devices compared with the previous ptn+otn group

traditional wavelength division includes optical layer veneers such as combining and dividing veneers, ROADM veneers, amplification boards, etc. the system is complex, and its planning, operation and maintenance are more complex, including dispersion compensation, OSNR, optical power balance and many other factors. Unreasonable planning will also lead to wavelength blocking and other problems. When potn is applied in the convergence access layer, the demand for wavelength scheduling is not obvious, and the general distance is within 80km; The convergence access layer involves a large number of products, and the convergence access network maintenance personnel are relatively inexperienced in wavelength division maintenance; Coupled with the tight space in the convergence room, these factors require the integration of potn's wavelength division function, reducing equipment costs and improving equipment integration

Pic is a photon integration technology. A pic module is equivalent to a simple wavelength division system. Potn adopts pic technology to improve the integration of line side optical interface and system, save costs, and simplify the planning, operation and maintenance of optical layer. In addition, PIC adopts the all electric relay method to group, which avoids the scheduling of och layer, which can realize more flexible network applications and avoid the problems of long project start time and service congestion caused by wavelength planning

at present, mature commercial pic can provide 1010g bandwidth, and the bandwidth m 1010g on the line side can be further improved through wave band combining and splitting (M is the number of PIC in wave band combining and splitting). It is expected that 825g and 4100g pic technologies will be gradually commercialized in one to two years

if the 10-10g pic technology is adopted, when the service rate is higher than the 10g interface rate, the physical layer aggregation method can be considered. Otu3 can carry 40g signals with four 10g wavelengths according to the standard otl3.4 interface. If the service capacity reaches 100g, 10 channels can also be bundled, that is, otu4 can be inversely multiplexed to otl4.10 interface

reconstruct the mapping path

mpls-tp service can be transmitted through OTN in the following two ways:

the process of mode 1 is: Service MPLS TP eth GFP encapsulation ODUk; The process of mode 2 is: business MPLS TP GFP encapsulation ODUk

the Ethernet encapsulation of mode 1 has no practical significance, which will only increase the overhead and reduce the bandwidth utilization of the potn device. Therefore, the Ethernet layer is generally omitted for the service encapsulation of the potn device. The packaging efficiency of potn (mode 2) is much higher than that of traditional PTN packaging. For example, for 64 byte services, the carrying efficiency of potn (mode 2 packaging) is 20% higher than that of PTN's existing Ethernet packaging, which brings great advantages to practical applications. For example, the user business is Ge rate. The output of three major synthetic materials in China has increased from 1.42 million tons in 1981. Due to packaging consumption, PTN's line side Ge interface is used to carry, The Ge service on the user side will not be able to achieve wire speed forwarding, but if the potn adopts MPLS-TP over ODUk packaging, the Ge service on the user side can fully support wire speed forwarding

ptn has perfect hierarchical OAM, but it has a certain lack of link error detection ability. MPLS-TP defines LM function, which can detect the packet loss caused by link error, but LM can only be carried out according to specific priority, which is difficult to reflect the condition of the whole link. FCS of Ethernet can detect the packet loss caused by link error. Considering the randomness of packet length and the non-uniformity of packet flow, when the packet flow on the line is small, the detection of link error is more inaccurate. Alta, a California electric bicycle expert, is a leading manufacturer of such devices because all electromechanical devices are exposed.

in order to improve the FCS based error detection of Ethernet ports, the background flow can be appropriately increased according to the business situation. When the business flow is less than the threshold, the background flow will be automatically sent, and when it is greater than the threshold, it will be automatically stopped. At the same time, when the receiving end receives the background flow, it will only be discarded after FCS detection, This can effectively improve the error rate detection effect, but compared with the inherent performance monitoring of sdh/otn, the error rate detection is still not accurate enough

in the hierarchical OAM of potn, the adjacent layers belong to the customer service model, and the OAM processing mechanism is usually triggered by the service layer, but the alarm performance reproduction can also be used across layers. For example, in the PE node, the protection switching of PW layer can be triggered directly according to the Los alarm, and there is no need to carry out alarm detection step by step. In the P node of LSP, according to the BIP performance detection of ODU layer, the Fei message transmission of LSP is triggered, and in the PE node of LSP, According to the Fei message, the LSP bit error status is counted, and the SD switching of LSP is triggered

end to end protection

potn equipment, MPLS-TP layer has lsp/pw linear protection, PTN shared ring protection, dual return protection, etc., OTN layer has ODU linear protection, ODUk shared ring protection, etc. How the OTN layer cooperates with the protection of the PTN layer and how the multi-layer protection integrates, we should focus on the following factors: the end-to-end protection of user services is mainly realized by the protection of PTN, and the protection of OTN layer mainly realizes the resistance to multi-point failure and cooperation to reduce the waste of bandwidth

the client layer should support starting the hold off timer machine to check whether the experimental sample system can be firmly fixed. At present, the delay time of ITU-T standard specification is at least 100ms, and the step length is 100ms; Under the condition that the service layer protection mechanism can strictly meet 50ms, in order to further shorten the service damage time, it is recommended to support the optimized delay time configuration of 50ms and the step size of 50ms

the potn network should locate the network level where the fault occurs according to the alarm correlation analysis to determine whether to start the delay time of the customer layer. The service layer should timely inform the customer layer whether the network protection of its service layer is successful or failed, so that the customer layer can start the network protection mechanism of the customer layer in a shorter time after knowing that the protection of the service layer has failed

potn provides the best multi-layer network optimization scheme. The forwarding plane adopts a unified switching matrix that can support any proportion of packet and TDM switching, omitting a large number of boards with repeated functions, and improving equipment integration; Through the application of PIC, the optical layer reduces a large number of optical layer veneers and equipment fiber hopping; Through the optimization of electrical layer packaging mapping, the service carrying efficiency of potn is improved and the network level is optimized; Through the optimization of OAM and protection, the advantages of PTN and OTN are complementary, unnecessary redundancy is reduced, and the self-healing ability of the network is further enhanced

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