Author: Lu Dongming
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Description: transport two line internet packet core network load balancing configuration mode, does not distinguish between primary backup, two core network side receives scrambled RTP packet causes high loss.
XX cities daily urban VOLTE test, the higher the overall RTP packet loss, packet loss TOPN selected high area, high packet loss community concentrated in the west region, the most severe TOP district packet loss rate of 90%. Lossy cell distribution as follows:
Select a site of high packet loss, by positioning each node capture, capture process node is a base station side - side transmission PTN - transmission convergence layer side - IMS core network side, troubleshooting path below:
1. The base station side - a core network side:
Lossless base station uplink, normal sort, the base station uplink contract normally. Two core network side receives an uplink data packet, so two core network sends a downlink data packet, and the packet out of order arrangement.
The base station 710 transmits an uplink data packet, the sequence from 0 to 709, normal sort.
The base station side receives two packets, the partial packets scrambled arrangement, the terminal directly affect RTP packet loss rate.
2. A base station side à of PTN side à transmission convergence layer side:
When the base station reports a data packet side, two transmission convergence layer receives data packets transmitted query PTN configuration, type of protection pseudo wire PW 1 + 1 dual transmitters and two receivers. PW twin lead transmission packet received two converging side.
PTN transmission station configuration inquiries, PW PW protection type 1 + 1 into a dual-income double PW 1: 1 single dual-income.
VOLTE-site testing, RTP packet loss rate below 5%, high packet loss problem is resolved, the field test shots are as follows:
PTN transmission side data forwarding configuration instructions:
The current scene in the cities of the provinces as well as the initial investment in a more comfortable building local networks are using this architecture to deploy. Wherein, of PTN access aggregation L2 VPN device uses a packet forwarding function configured pseudowires dual-homing protection, the access layer device may be configured as a single or double service.
单发：数据只通过工作或者保护伪线转发到L3VPN，然后再转发到核心网EPC，EPC只能收到一份数据报文。
双发：数据通过同时工作和保护伪线转发到L3VPN，然后又同时被转发到EPC，如果EPC与PTN对接的两条路由配置为主备模式，此时EPC只能通过主用或者备用(倒换后)接收到一份数据。如果EPC与PTN对接的两条路由配置为负荷分担模式，即EPC同时从两个方向接收数据包，则对于双发这种场景，EPC会接收到双份数据包。