QCI的作用，比如打电话，打电话有一个过程，首先会建立信道，中间在建立一个EPS bearer，在EPS中会携带者一个qci。可以直接看QCI描述。
可以直接查看百度百科：QCI百度百科
QCI表示Qos类别指示。这是一种特定标识 ，其定义了LTE数据报通信的质量。
QCIL类别范围 1~9（每个类别的定义如下表所示）
QCIResource TypePriorityPacket Delay Budget(NOTE 1)Packet Error Loss Rate(NOTE 2)Example Services 1
GBR2100 msConversational Voice24150 msConversational Video（Live streaming）3350 msReal Time Gaming 45300 msNon-conversational voice(buffered streaming)5Non-GBR1100 msIMS signaling66300ms Video (buffered streaming), TCP-based (e.g. www, email, chat, ftp, p2p file sharing, progressive video,etc)
77100 ms Voice, Video (live streaming), interactive gaming
88300 ms Video (buffered streaming), TCP-based (e.g. www, email, chat, ftp, p2p file sharing, progressive video,etc)
99 Video (buffered streaming), TCP-based (e.g. www, email, chat, ftp, p2p file sharing, progressive video,etc)
QCI9 : 是LTE默认承载，任何4G终端驻留4G的时候QCI9常驻；
QCI5 : 是IMS消息专用通道，就是支持VOLTE的终端打开了VOLTE就一直存在QCI9+5；
QCI1 : 是VOLTE语音通道，通话的时候就建立，VOLTE终端通话的时候就是QCI9+5+1；
QCI2 : 是VOLTE视频通话通道，视频通话的时候建立，VOLTE终端视频通话的时候就是QCI9+5+1+2；
注意：
通过 “Activate default EPS bearer context request” 消息来给每一个UE 分配特定的QCI值并通知到UE 信令如：
Activate default EPS bearer context request ::= DIVISION
. ...
EPS quality of service
Length: 1
Quality of Service Class Identifier (QCI): QCI 9 (9) //QCI
Activate dedicated EPS bearer context request ::= DIVISION
. ...
EPS quality of service
Length: 5
Quality of Service Class Identifier (QCI): QCI 1 (1)
Maximum bit rate for uplink : 1 kbps
Maximum bit rate for downlink : 1 kbps
Guaranteed bit rate for uplink : 1 kbps
Guaranteed bit rate for downlink : 1 kbps
QCI描述
GBRQCI=1Example Services: Conversational voicemscbscQCI=2Conversational Video (Live streaming)QCI=3Real Time GamingQCI=4Non-conversational voice (buffered streaming)Non-GBRQCI=5IMS signalingQCI=6Video (buffered streaming), TCP-based (e.g. www, email, chat, ftp, p2p file sharing, progressive video,etc)QCI=7Voice, Video (live streaming), interactive gamingQCI=8Video (buffered streaming), TCP-based (e.g. www, email, chat, ftp, p2p file sharing, progressive video,etc)QCI=9Video (buffered streaming), TCP-based (e.g. www, email, chat, ftp, p2p file sharing, progressive video,etc) QCI9是LTE默认承载，任何4G终端驻留4G的时候QCI9常驻；
QCI5是IMS消息专用通道，就是支持VOLTE的终端打开了VOLTE就一直存在QCI9+5；
QCI1是VOLTE语音通道，通话的时候就建立，VOLTE终端通话的时候就是QCI9+5+1；
QCI2是VOLTE视频通话通道，视频通话的时候建立，VOLTE终端视频通话的时候就是QCI9+5+1+2；