Utms signaling training (1)

End-to-End Bearing of Signaling

In UMTS end-to-end bearer, QoS can ensure the range between UU-lu ports, that is, our own network. In network establishment, we need to rely on signaling to establish connections and allocate the bearer. Notes:

1. Rab is allocated by RNC.

2. When we have a call, MSC Xianzhi has a call and then notifies RNC that RNC will complete the allocation.

When carrying 3G data, you can select over IP or over ATM. Starting from rel5, the 3G load is switched to over IP.

Over IP

Currently, in the PS domain, UDP is used for both the control and user plane. To improve the reliability of UDP, we use the GTPs and sctp protocols to improve its reliability. Transmission signaling can be transmitted through the GTP-C or by mtp3 directly through sctp. The method of using the GTPs must be reliable in the internal link of the group domain, and mtp3 is transmitted through sctp externally.

RTP/RTCP

The RTP protocol details the standard packet formats for transmitting audio and video on the Internet. It was initially designed as a multicast protocol, but was later used in many unicast applications. RTP protocol is often used in streaming media systems (with RTSP protocol), video conferencing and one-click push
To talk) system (with H.323 or sip), making it the technical basis of the IP phone industry. The RTP protocol is used together with the RTP control protocol RTCP, And it is created on the UDP protocol.

RTP Control Protocol (RTCP) uses the same distribution mechanism as data packets to periodically transmit control packets to all session participants. The underlying protocol must provide multi-path transmission of data and control packets. That is to say, RTCP is the control and feedback of RTP QoS.

ATM

AAL:

It is used for real-time traffic and provides low latency. The information of multiple users in AAL 2 can be placed in a 53bit ATM Cell. (Mini package ). The signal reported by the mobile phone is also transmitted between BTS and RNC through AAL.

AAL5:

Suitable for large data packets. Generally, it is a PS group business and signaling.

When used for transmission signaling, you also need to adapt to Saal

This layer is used to ensure the transmission sequence, error correction, and other protection functions.