Key to integration of PTN and TD maintenance under the FTTH Trend

During the PTN Network Period, the integration of transmission-side and wireless-side maintenance must be put on the agenda. First, the core technology of the PTN network is Packet Exchange. The "Elastic Pipeline" feature gives the technology the advantages of statistical reuse, greatly improving the resource utilization of the network, it also brings about problems such as how to implement emergency communication protection without affecting the transmission network structure by analyzing network traffic. Second, the technology deploys a powerful HQoSHierarchical Quality of Service, hierarchical QoS) function. Different types of services must be configured with different QoS attributes, how to reasonably develop QoS policies for the business to achieve the quality of service required by the wireless side will become very urgent. In addition, compared with SDH, the PTN Transmission Fault Circuit is more complex and recessive due to packet loss caused by network congestion. The above three requirements require the transmission side to abandon the outdated maintenance concepts and working methods of the traditional SDH network, and strengthen communication with wireless networks, understand the features of wireless services, including traffic and QoS, in a timely manner, so as to give full play to the advantages of the PTN technology.

Implement joint deployment of QoS policies

QoS is a capability of a network, that is, a network that spans multiple underlying network technologies, such as MP, FR, ATM, Ethernet, SDH, and MPLS, provide services required by specific services, and obtain predictable service levels in terms of packet loss rate, latency, jitter, and bandwidth. The PTN device has a powerful HQoS hierarchical QoS function. It can deploy QoS policies of five levels, namely UNI, V-UNI, PW, Tunnel, and NNU, seven different service levels are implemented for CS7, CS6, EF, AF4, AF3, AF2, AF1, and BE to fully meet the needs of all business scenarios, service-level requirements for different types of businesses.

With the deepening of China Mobile's full-service strategy, China Mobile will provide more and more business types in the next few years. In addition to traditional voice services, home Internet services, group data services, and videophone services will also become part of the company's revenue. Different service levels have different requirements for transmission networks, such as bandwidth and latency.

In the past, SDH/MSTP networks were hard pipes. Regardless of whether the network was hosted or not, it would also occupy the resources of the transmission network, and the utilization of network resources was not high. SDH/MSTP is a technology that meets specific needs in a specific era and is outdated. The PTN technology provides a "soft pipeline". Its biggest advantage is that if the pipeline does not carry actual services, it will not occupy transmission resources, which greatly enhances the flexibility of the network, it also maximizes the utilization of transmission resources. Therefore, for wireless businesses with different service quality requirements, it is no longer reasonable to expect all businesses to be delivered of the same quality on the transmission network as they used in the past. The transmission side and the wireless side should reach a consensus on QoS policies, as shown in Table 1), so that wireless services with different service quality needs can be delivered in a more cost-effective manner in the transmission network.

Implement synchronous switching of LAG Protection between PTN-RNC

The LAG link aggregation group between the Huawei PTN3900 device and the Huawei DRNC820 device. If the PTN device received light-35db, the device reported the ETH-LOS alarm may be reversed, but does not affect the replacement), but the code stream sent by both parties is still normal, at this time PTN side has been reversed, the peer RNC has no response and no replacement has occurred. The non-synchronous switching of the LAG Protection will cause all the sites hosted by the RNC port to return to the server, which has a great impact. In response to the above faults, communication between the transmission side and the wireless side should be strengthened to jointly develop solutions.

(Optional) Scheme 1): In the current manual LAG connection mode, the PTN and RNC devices simultaneously have the "Automatic shutdown function ", this method is a mature solution jointly developed by Huawei's PTN product line and RNC product line to solve this problem.

(Optional): static LAG mode. LACP is enabled for both parties. The two parties solve this problem through protocol message interaction.

3G service PTN bearer cutover collaboration

3G services are cutover from SDH network to PTN network based on the following considerations: 1) SDH network capacity is becoming increasingly saturated, so it is necessary to free up capacity to meet the service load requirements such as the failure of PTN devices to install sites; 2) the PTN network is becoming more and more stable, and maintenance personnel have certain self-maintenance capabilities. It is time for the PTN network to carry 3G services in batches. 3) compared with SDH network, the 3G network is more efficient to carry services from the PTN network.

In addition, the PTN bearer cutover of 3G services requires that the transmission side and the wireless side work collaboratively. the disconnection of any step may affect the project progress:

Step 1: Provide a cut-over site list on the wireless side. Note that if the new RNC port is involved, the wireless side should be proposed as soon as possible. In addition, the wireless side must provide the following data: the total number of cutover sites, the number of sites in each data center, the number of RNC involved in cutover, and the number of sites attached to each RNC.

Step 2: The transport side confirms the following factors based on the planned site list. This step is critical and any link may affect the overall cutover schedule. 1) confirmation of the PTN landing port: based on the data provided by the wireless side, determine whether to add the port of the landing device. If necessary, complete the mounting relationship in advance and arrange the jumper. 2) Confirm GE channel capacity: based on the data provided by the wireless side, check whether the GE channel between the backbone device and the landing device has sufficient capacity to carry the site business. If not, you should add a new Wavelength Division Channel in advance. 3) Confirmation of Wavelength Division Channel: if a new port is added and the port on the new device is added, a new Wavelength Division Channel is required. 4) confirmation of the wavelength division system: if a new Wavelength Division Channel is required, check whether factors such as the TOM board port of the wavelength division device are met. 5) Confirmation of engineering materials: FC/FC jumpers with a length of 3 m, 10 m and 15 m, and light attenuation of 3dBm and 5dBm should be used during the engineering process. 6) troubleshooting of current network element faults: There are two main types of network element faults for commissioning and testing. The first category is the pipe disconnection caused by fiber disconnection, the second type is the BBU and PTN connection faults during the project. The above two types of faults need to be arranged in advance to reserve sufficient time for the subsequent troubleshooting.

Step 3: Based on the Site List check results, the transmission side organizes business configuration for sites that have the cutover conditions. For sites that do not have the cutover conditions, quickly organize personnel to troubleshoot the problems.

Step 4: submit a list of sites that have completed business configuration on the transmission side wireless side, organize the wireless side to perform Ping tests, and report the Ping tests.

Step 5: Transport-side organizations analyze and exclude sites that fail the Ping test.

Step 6: organize the site cutover on the wireless side, and arrange for emergency personnel on the transmission side.

Strengthen collaborative analysis of service performance faults

Wireless Services are deteriorated in terms of Service quality. When the packet loss rate, delay, jitter, bandwidth, and other parameters cannot meet the SLA (Service Level Agreement) requirements, it is obviously not enough to rely solely on wireless participation. In this scenario, the wireless and transmission sides need to strengthen the collaborative analysis of service performance faults:

1) analyze the causes of wireless service performance degradation and locate the specific degraded parameter packet loss rate, latency, jitter, etc );

2) query the specific values of the above degradation parameters on the wireless and transmission network interfaces;

3) identify fault points and troubleshoot them.

With the deepening of the whole business operation strategy, technological innovation is becoming the main melody of the communication industry. In terms of Metro bearer networks, the biggest technological innovation lies in the introduction of PTN technology. Under the new technology, some traditional SDH-Based O & M concepts and maintenance methods need to be abandoned. How to strengthen the joint operation with the wireless side has been put on the discussion agenda.