在通信系统中参与的终端（UA）之间信息的交互全部基于自身能力（Capability Information）；通常他们交换自身能力是初始通信设置中的一个强制内容，有时终端提供这些信息则是为了回应对方的特殊要求。在WCDMA或LTE网络中，终端是在RRC连接配置完成消息中携带这些表明其性能的特殊消息。
这些有关自身能力（Capability Information）的信息对于沟通中的双方来说都非常重要；这些信息可以自行配置后才可以与另一方进行沟通。此外在进行即时消息交流时这些信息也非常重要，因为在许多情况下信息交流失败仅仅是因为终端不支持特定功能或特性。
在IMS系统和基于IMS系统的应用程序中也使用类似的机制。对于IMS应用程序有几种不同的机制消息，它们都携带了UE能力相关信息。对于IMS系统的故障排除，在开始进行故障排除之前，最好检查一下UE功能的相关信息。
1.IMS系统中携带UE能力的SIP消息
在IMS系统以下七种消息中携带了含有UE能力的消息，这些消息分别表明了其支持的功能或性能；
2.携带UE能力的消息内容（下文中红色字体部分）
2.1 注册（Capability Information in REGISTER）
REGISTER sip:test.3gpp.com SIP/2.0
Route: <sip:[2001:0:0:1::2]:5060;lr>
Allow: INVITE,ACK,OPTIONS,CANCEL,BYE,UPDATE,INFO,REFER,NOTIFY,MESSAGE,PRACK
Expires: 600000
Authorization: Digest username="001010123456789@test.3gpp.com",realm="TestIMS.com",
nonce="fn3iiH1LnWqCtFyPUD8qzYxfiiVavYAAmfcxByxmhBg=",algorithm=AKAv1-MD5,
uri="sip:test.3gpp.com",response="9f17517adee640b8895dda33b336f071",
qop=auth,nc=00000002,cnonce="dsf232sun2299674910xyx",
opaque="bbedd3dd5f884860b741b03d36b430ea"
P-Access-Network-Info: 3GPP-E-UTRAN-FDD;utran-cell-id-3gpp=0010100010000001
Contact: <sip:+11234567890@[2001:0:0:1::1]:5060>;
+g.3gpp.smsip;
+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel";video;
+g.gsma.rcs.telephony="cs,volte";
+sip.instance="<urn:gsma:imei:99000493-686661-0>"
From: <sip:+11234567890@test.3gpp.com>;tag=1334507655
To: <sip:+11234567890@test.3gpp.com>
Call-ID: 266901530@2001:0:0:1::1
CSeq: 4 REGISTER
Max-Forwards: 70
Via: SIP/2.0/UDP [2001:0:0:1::1]:5060;branch=z9hG4bK459934981smg;transport=UDP
Content-Length: 0
2.2 发布（Capability Information in PUBLISH）
PUBLISH sip:+339012341234@test-rcs.com SIP/2.0
Call-ID: xSh0yaUHAA@192.168.1.1
CSeq: 1 PUBLISH
From: <sip:+339012341234@test-rcs.com>;tag=xSh0yaUIAA
To: <sip:+339012341234@test-rcs.com>
Via: SIP/2.0/UDP 192.168.1.1:5060;branch=z9hG4bK84da5f074a2ba56ea1c0d63f7fa45a54383138;rport
Max-Forwards: 70
Route: <sip:192.168.1.2:5060;transport=udp;lr>
Expires: 3600
SIP-If-Match: ac63be7e9042439dad76da16904cf48d
User-Agent: IM-client/OMA1.0 Test-RCS-client/2.5.13
Event: presence
Content-Type: application/pidf+xml
Content-Length: 2122
<presence
xmlns="urn:ietf:params:xml:ns:pidf"
xmlns:op="urn:oma:xml:prs:pidf:oma-pres"
xmlns:opd="urn:oma:xml:pde:pidf:ext"
xmlns:pdm="urn:ietf:params:xml:ns:pidf:data-model"
xmlns:ci="urn:ietf:params:xml:ns:pidf:cipid"
xmlns:rpid="urn:ietf:params:xml:ns:pidf:rpid"
xmlns:gp="urn:ietf:params:xml:ns:pidf:geopriv10"
xmlns:gml="urn:opengis:specification:gml:schema-xsd:feature:v3.0"
entity="sip:+339012341234@test-rcs.com">
<tuple id="t1">
<status><basic>open</basic></status>
<op:service-description>
<op:service-id>org.openmobilealliance:File-Transfer</op:service-id>
<op:version>1.0</op:version>
</op:service-description>
<contact>sip:+339012341234@test-rcs.com</contact>
<timestamp>2014-06-19T06:30:45.000Z</timestamp>
</tuple>
<tuple id="t2">
<status><basic>open</basic></status>
<op:service-description>
<op:service-id>org.gsma.imageshare</op:service-id>
<op:version>1.0</op:version>
</op:service-description>
<contact>sip:+339012341234@test-rcs.com</contact>
<timestamp>2014-06-19T06:30:45.000Z</timestamp>
</tuple>
<tuple id="t3">
<status><basic>open</basic></status>
<op:service-description>
<op:service-id>org.gsma.videoshare</op:service-id>
<op:version>1.0</op:version>
</op:service-description>
<contact>sip:+339012341234@test-rcs.com</contact>
<timestamp>2014-06-19T06:30:45.000Z</timestamp>
</tuple>
<tuple id="t4">
<status><basic>open</basic></status>
<op:service-description>
<op:service-id>org.openmobilealliance:IM-session</op:service-id>
<op:version>1.0</op:version>
</op:service-description>
<contact>sip:+339012341234@test-rcs.com</contact>
<timestamp>2014-06-19T06:30:45.000Z</timestamp>
</tuple>
<tuple id="t5">
<status><basic>open</basic></status>
<op:service-description>
<op:service-id>org.3gpp.cs-videotelephony</op:service-id>
<op:version>1.0</op:version>
</op:service-description>
<contact>sip:+339012341234@test-rcs.com</contact>
<timestamp>2014-06-19T06:30:45.000Z</timestamp>
</tuple>
</presence>
2.3选项（Capability Information in OPTION）
OPTIONS sip:192.168.1.1:5060;transport=udp SIP/2.0
Via: SIP/2.0/UDP 192.168.1.2:51422;branch=z9hG4bKb7a8715cd9d04e019149483fac110beea0;rport;transport=udp
Via: SIP/2.0/TCP 192.168.1.2:49755;branch=z9hG4bKec290e95eb714990adc88d84f09a6367;rport=49836
Max-Forwards: 69
From: <sip:+330123456789@sharetechnote-rcs.com>;tag=33ad62399bdc451d92591e2d9e29903a
To: <sip:+339012341234@sharetechnote-rcs.com>
Date: Thu, 19 Jun 2014 15:40:39 GMT
Expires: 3600
Contact: <sip:+330123456789@sharetechnote-rcs.com>;
+g.3gpp.cs-voice;video;
+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.oma.cpm.msg,
urn%3Aurn-7%3A3gpp-service.ims.icsi.oma.cpm.largemsg,
urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel";
+g.3gpp.iari-ref="urn%3Aurn-7%3A3gpp-application.ims.iari.rcse.im,
urn%3Aurn-7%3A3gpp-application.ims.iari.rcs.fullsfgroupchat,
urn%3Aurn-7%3A3gpp-application.ims.iari.rcs.ftthumb,
urn%3Aurn-7%3A3gpp-application.ims.iari.rcs.fthttp,
urn%3Aurn-7%3A3gpp-application.ims.iari.rcse.sp,
urn%3Aurn-7%3A3gpp-application.ims.iari.rcse.dp,
urn%3Aurn-7%3A3gpp-application.ims.iari.rcs.geopull"
CSeq: 1 OPTIONS
Call-ID: 334cb0b603964d348a011fc8f87c82cd
Content-Length: 0
Record-Route: <sip:192.168.1.2;lr>
2.4通知（Capability Information in NOTIFY）
SUBSCRIBE sip:+14448880000@one.att.net SIP/2.0
Allow: INVITE,ACK,OPTIONS,CANCEL,BYE,UPDATE,INFO,REFER,NOTIFY,MESSAGE,PRACK
User-Agent: Samsung IMS 5.0
Accept-Encoding: gzip
Expires: 0
Privacy: id
Accept: application/pidf+xml,multipart/related,application/rlmi+xml
P-Preferred-Identity: <sip:310410123456789@one.att.net>
CSeq: 1 SUBSCRIBE
Max-Forwards: 70
P-Access-Network-Info: 3GPP-E-UTRAN-FDD;utran-cell-id-3gpp=31041000010000000
Route: <sip:[2001:0:0:1::2]:5060;lr>
a: *;+g.oma.sip-im;explicit;require
f: <sip:Anonymous@one.att.net>;tag=1750499527
i: 1148937124@2001::1:4c16:9c0f:4986:9e6d
l: 0
m: <sip:310410123456789@[2001::1:4c16:9c0f:4986:9e6d]:5060>
o: presence
t: <sip:+14448880000@one.att.net>
v: SIP/2.0/UDP [2001::1:4c16:9c0f:4986:9e6d]:5060;branch=z9hG4bK2869593858smg;transport=UDP
NOTIFY sip:310410123456789@[2001::1:4c16:9c0f:4986:9e6d]:5060;transport=udp SIP/2.0
Max-Forwards: 69
Via: SIP/2.0/UDP [2001:0:0:1::2]:5060;branch=z9hG4bK2734c4ccb25347249de8a9cc2b95e81f10;rport
From: <tel:+14448880000>;tag=987654321
To: <sip:310410123456789@[2001::1:4c16:9c0f:4986:9e6d]:5060>;tag=1750499527
Event: presence
Contact: <sip:[2001:0:0:1::2]:5060>
Content-Type: application/pidf+xml
Subscription-State: active;expires=3600
CSeq: 1 NOTIFY
Call-ID: 1148937124@2001::1:4c16:9c0f:4986:9e6d
Content-Length: 2097
<?xml version="1.0" encoding="UTF-8"?>
<presence xmlns="urn:ietf:params:xml:ns:pidf"
xmlns:rpid="urn:ietf:params:xml:ns:pidf:rpid"
xmlns:op="urn:oma:xml:prs:pidf:oma-pres"
xmlns:pdm="urn:ietf:params:xml:ns:pidf:data-model"
xmlns:cipid="urn:ietf:params:xml:ns:pidf:cipid"
xmlns:caps="urn:ietf:params:xml:ns:pidf:caps"
entity="sip:+14448880000@one.att.net">
<tuple id="SessModeMessa">
<status><basic>open</basic></status>
<op:service-description>
<op:service-id>org.openmobilealliance:ChatSession</op:service-id>
<op:version>2.0</op:version>
<op:description>Session Mode Messaging</op:description>
</op:service-description>
<contact>sip:+14448880000@one.att.net</contact>
</tuple>
<tuple id="FileTransfer1">
<status><basic>open</basic></status>
<op:service-description>
<op:service-id>org.openmobilealliance:File-Transfer</op:service-id>
<op:version>1.0</op:version>
<op:description>File Transfer</op:description>
</op:service-description>
<contact>sip:+14448880000@one.att.net</contact>
</tuple>
<tuple id="DiscoveryPres">
<status><basic>open</basic></status>
<op:service-description>
<op:service-id>org.3gpp.urn:urn-7:3gpp-application.ims.iari.rcse.dp</op:service-id>
<op:version>1.0</op:version>
<op:description>DiscoveryPresence</op:description>
</op:service-description>
<contact>sip:+14448880000@one.att.net</contact>
</tuple>
<tuple id="StandaloneMsg">
<status><basic>open</basic></status>
<op:service-description>
<op:service-id>org.openmobilealliance:StandaloneMsg</op:service-id>
<op:version>2.0</op:version>
<op:description>StandaloneMsg</op:description>
</op:service-description>
<contact>sip:+14448880000@one.att.net</contact>
</tuple>
<tupleid="VOLTE15456546">
<status><basic>open</basic></status>
<caps:servcaps>
<caps:audio>true</caps:audio>
<caps:video>true</caps:video>
<caps:duplex><caps:supported>
<caps:full />
</caps:supported>
</caps:duplex>
</caps:servcaps>
<op:service-description>
<op:service-id>org.3gpp.urn:urn-7:3gpp-service.ims.icsi.mmtel</op:service-id>
<op:version>1.0</op:version>
<op:description>IPVideoCall</op:description>
</op:service-description>
<contact>sip:+14448880000@one.att.net</contact>
</tuple>
</presence>
2.5邀请（Capability Information in INVITE）
INVITE sip:310410123456789@[2001::1:f8b5:503a:c5d0:2fea]:6000 SIP/2.0
Via: SIP/2.0/UDP [2001:0:0:1::2]:62993;branch=z9hG4bKd7e3f6cf946a49618e8be0a37cc4a65b53;transport=udp
Via: SIP/2.0/UDP [2001:0:0:1::2]:62984;branch=z9hG4bK3a2fa06cd53440b7a93217d703d8792a963b2071
Max-Forwards: 69
Call-ID: bbae9438711d47d283895a10f920c2db
CSeq: 11001 INVITE
To: <sip:310410123456789@sharetechnote.net>
From: <sip:0123456789@sharetechnote.net>;tag=1111111111
Feature-Caps: +g.3gpp.srvcc-alerting
Allow: ACK, BYE, CANCEL, INVITE, PRACK, UPDATE
Accept-Contact: *;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel";require;explicit
User-Agent: Test-VirtualUA/95adfae
Content-Type: application/sdp
Content-Length: 456
Contact: <sip:0123456789@[2001:0:0:1::2]:62984;transport=udp>;+g.3gpp.icsi-ref="urn:urn-7:3gpp- service.ims.icsi.mmtel";video;+g.3gpp.srvcc-alerting
Privacy: none
P-Asserted-Identity: <sip:0123456789@sharetechnote.net>
Record-Route: <sip:[2001:0:0:1::2]:62993;lr>
2.6180振铃（Capability Information in 180 Ringing）
SIP/2.0 180 Ringing
Max-Forwards: 70
Allow: INVITE,ACK,CANCEL,BYE,UPDATE,INFO,REFER,NOTIFY,MESSAGE,PRACK
CSeq: 11001 INVITE
Record-Route: <sip:[2001:0:0:1::2]:62993;lr>
P-Access-Network-Info: 3GPP-E-UTRAN-FDD;utran-cell-id-3gpp=31041000010000001
f: <sip:0123456789@sharetechnote.net>;tag=1111111111
i: bbae9438711d47d283895a10f920c2db
l: 0
m: <sip:310410123456789@[2001::1:f8b5:503a:c5d0:2fea]:6000>;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel";require;explicit;+g.3gpp.srvcc-alerting;mobility="mobile"
t: <sip:310410123456789@sharetechnote.net>;tag=506663245
v: SIP/2.0/UDP [2001:0:0:1::2]:62993;branch=z9hG4bKd7e3f6cf946a49618e8be0a37cc4a65b53;transport=udp,SIP/2.0/UDP [2001:0:0:1::2]:62984;branch=z9hG4bK3a2fa06cd53440b7a93217d703d8792a963b2071
2.7 200（OK）Capability Information in 200 OK
SIP/2.0 200 OK
Accept: application/sdp,application/3gpp-ims+xml
Allow: INVITE,ACK,CANCEL,BYE,UPDATE,INFO,REFER,NOTIFY,MESSAGE,PRACK
Security-Verify: ipsec-3gpp;q=0.1;alg=hmac-md5-96;ealg=null;prot=esp;mod=trans;spi-c=2340907816;spi- s=1826487465;port-c=62992;port-s=62993
Max-Forwards: 70
User-Agent: Samsung IMS 5.0
CSeq: 11001 INVITE
Record-Route: <sip:[2001:0:0:1::2]:62993;lr>
P-Access-Network-Info: 3GPP-E-UTRAN-FDD;utran-cell-id-3gpp=31041000010000001
c: application/sdp
f: <sip:0123456789@sharetechnote.net>;tag=1111111111
i: bbae9438711d47d283895a10f920c2db
k: timer
l: 375
m: <sip:310410123456789@[2001::1:f8b5:503a:c5d0:2fea]:6000>;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp- service.ims.icsi.mmtel";require;explicit;+g.3gpp.mid-call;mobility="mobile"
t: <sip:310410123456789@sharetechnote.net>;tag=506663245
v: SIP/2.0/UDP [2001:0:0:1::2]:62993;branch=z9hG4bKd7e3f6cf946a49618e8be0a37cc4a65b53;transport=udp,SIP/2.0/UDP [2001:0:0:1::2]:62984;branch=z9hG4bK3a2fa06cd53440b7a93217d703d8792a963b2071
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