IETF RFCs Supported by Lync

I was responding to an RFP, and one of the questions was a list of the IETF RFCs that Lync supported.  There didn't seem to be a central list anywhere, so I compiled a list myself.  If you're in a similar situation where you need this kind of info, hopefully this will help!  Much of this was taken from Microsoft's official protocol documentation at http://msdn.microsoft.com/en-us/library/cc307282(v=office.12).aspx.  If the RFC was listed in the Normative References section, I added it here.  The RFC may not be followed to the letter, and may have been added on to as well.
Any additions or corrections would be greatly appreciated. 

RFC #	Description	Relates To	Link
RFC 1321	The MD5 Message-Digest Algorithm	Security	http://tools.ietf.org/html/rfc1321
RFC 2045	Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies	Conferencing	http://tools.ietf.org/html/rfc2045
RFC 2104	HMAC: Keyed-Hashing for Message Authentication	Security	http://tools.ietf.org/html/rfc2104
RFC 2111	Content-ID and Message-ID Uniform Resource Locators	Telephony	http://tools.ietf.org/html/rfc2111
RFC 2118	Microsoft Point-To-Point Compression (MPPC) Protocol	Base	http://tools.ietf.org/html/rfc2118
RFC 2132	DHCP Options and BOOTP Vendor Extensions	Base	http://tools.ietf.org/html/rfc2132
RFC 2141	URN Syntax	Base	http://tools.ietf.org/html/rfc2141
RFC 2190	RTP Payload Format for H.263 Video Streams	Media	http://tools.ietf.org/html/rfc2190
RFC 2198	RTP Payload for Redundant Audio Data	Media	http://tools.ietf.org/html/rfc2198
RFC 2246	The TLS Protocol Version 1.0	Security	http://tools.ietf.org/html/rfc2246
RFC 2315	PKCS #7: Cryptographic Message Syntax Version 1.5	Security	http://tools.ietf.org/html/rfc2315
RFC 2459	Internet X.509 Public Key Infrastructure Certificate and CRL Profile	Security	http://tools.ietf.org/html/rfc2459
RFC 2474	QoS Differentiated Services	Network	http://tools.ietf.org/html/rfc2474
RFC 2716	PPP EAP TLS Authentication Protocol	Security	http://tools.ietf.org/html/rfc2716
RFC 2743	Generic Security Service Application Program Interface v2, Update 1	Security	http://tools.ietf.org/html/rfc2743
RFC 2782	A DNS RR for specifying the location of services (DNS SRV)	Base	http://tools.ietf.org/html/rfc2782
RFC 2818	HTTP Over TLS	Base	http://tools.ietf.org/html/rfc2818
RFC 2976	SIP INFO Method	Base	http://tools.ietf.org/html/rfc2976
RFC 2986	PKCS#10: Certificate Request Syntax Specification	Security	http://tools.ietf.org/html/rfc2986
RFC 3261	Session Initiation Protocol (SIP)	Base	http://tools.ietf.org/html/rfc3261
RFC 3262	Reliability of Provisional Responses in SIP	Base	http://tools.ietf.org/html/rfc3262
RFC 3264	An Offer/Answer Model with the Session Description Protocol (SDP)	Conferencing	http://tools.ietf.org/html/rfc3264
RFC 3265	SIP-Specific Event Notification	Base	http://tools.ietf.org/html/rfc3265
RFC 3311	SIP UPDATE Method	Base	http://tools.ietf.org/html/rfc3311
RFC 3323	A Privacy Mechanism for the Session Initiation Protocol (SIP)	Base	http://tools.ietf.org/html/rfc3323
RFC 3325	Private Extensions to the Session Initiation Protocol (SIP) for Asserted Identity within Trusted Networks	Telephony	http://tools.ietf.org/html/rfc3325
RFC 3326	The REASON Header Field for SIP	Base	http://tools.ietf.org/html/rfc3326
RFC 3327	SIP Extension Header Field for Registering Non-Adjacent Contacts	Base	http://tools.ietf.org/html/rfc3327
RFC 3350	Real-time protocol for media	Media	http://tools.ietf.org/html/rfc3350
RFC 3361	DHCP option for SIP servers	Telephony	http://tools.ietf.org/html/rfc3361
RFC 3389	Real-Time Transport Protocol (RTP) Payload for Comfort Noise (CN)	Telephony	http://tools.ietf.org/html/rfc3389
RFC 3420	Internet Media Type message/sipfrag	Media	http://tools.ietf.org/html/rfc3420
RFC 3428	Session Initiation Protocol (SIP) Extension for Instant Messaging	Base	http://tools.ietf.org/html/rfc3428
RFC 3515	SIP REFER Method	Base	http://tools.ietf.org/html/rfc3515
RFC 3550	RTP: A Transport Protocol for Real-Time Applications	Media	http://tools.ietf.org/html/rfc3550
RFC 3551	RTP Profile for Audio and Video Conferences with Minimal Control	Media	http://tools.ietf.org/html/rfc3551
RFC 3581	SIP Symmetric Response Routing	Base	http://tools.ietf.org/html/rfc3581
RFC 3605	Real Time Control Protocol (RTCP) Attribute in Session Description Protocol (SDP)	Media	http://tools.ietf.org/html/rfc3605
RFC 3611	RTP Control Protocol Extended Reports (RTCP XR)	Media	http://tools.ietf.org/html/rfc3611
RFC 3629	UTF-8, A Transformation Format of ISO 10646	Conferencing	http://tools.ietf.org/html/rfc3629
RFC 3711	Secure real-time protocol for media	Media	http://tools.ietf.org/html/rfc3711
RFC 3761	Telephone Number Mapping (ENUM)	Telephony	http://tools.ietf.org/html/rfc3761
RFC 3840	Indicating User Agent Capabilities in the Session Initiation Protocol (SIP)	Base	http://tools.ietf.org/html/rfc3840
RFC 3842	A Message Summary and Message Waiting Indication Event	Telephony	http://tools.ietf.org/html/rfc3842
RFC 3852	Cryptographic Message Syntax (CMS)	Security	http://tools.ietf.org/html/rfc3852
RFC 3863	Presence Information Data Format (PIDF)	Base	http://tools.ietf.org/html/rfc3863
RFC 3891	SIP REPLACES Header	Telephony	http://tools.ietf.org/html/rfc3891
RFC 3892	SIP Referred-by Mechanism	Telephony	http://tools.ietf.org/html/rfc3892
RFC 3960	Early Media and Ringing Tone Generation for SIP	Telephony	http://tools.ietf.org/html/rfc3960
RFC 3966	Tel URI for Telephone Numbers	Telephony	http://tools.ietf.org/html/rfc3966
RFC 3986	Uniform Resource Identifier (URI): Generic Syntax	Base	http://tools.ietf.org/html/rfc3986
RFC 4028	Session Timers in the Session Initiation Protocol	Conferencing	http://tools.ietf.org/html/rfc4028
RFC 4119	A Presence-based GEOPRIV Location Object Format	e911	http://tools.ietf.org/html/rfc4119
RFC 4120	The Kerberos Network Authentication Service (V5)	Security	http://tools.ietf.org/html/rfc4120
RFC 4121	The Kerberos Version 5 Generic Security Service Application Program Interface (GSS-API) Mechanism: Version 2	Security	http://tools.ietf.org/html/rfc4121
RFC 4122	A Universally Unique Identifier (UUID) URN Namespace	Base	http://tools.ietf.org/html/rfc4122
RFC 4145	TCP-Based Media Transport in the Session Description Protocol (SDP)	Media	http://tools.ietf.org/html/rfc4145
RFC 4235	An INVITE-Initiated Dialog Event Package for SIP	Base	http://tools.ietf.org/html/rfc4235
RFC 4244	An Extension to SIP for Request History Information	Base	http://tools.ietf.org/html/rfc4244
RFC 4353	A Framework for Conferencing with the Session Initiation Protocol (SIP)	Conferencing	http://tools.ietf.org/html/rfc4353
RFC 4480	RPID: Rich Presence Extensions to the Presence Information Data Format (PIDF)	Base	http://tools.ietf.org/html/rfc4480
RFC 4559	SPNEGO-based Kerberos and NTLM HTTP Authentication in Microsoft Windows	Security	http://tools.ietf.org/html/rfc4559
RFC 4566	SDP: Session Description Protocol	Media	http://tools.ietf.org/html/rfc4566
RFC 4568	Session Description Protocol (SDP) Security Descriptions for Media Streams	Media	http://tools.ietf.org/html/rfc4568
RFC 4571	Framing Real-time Transport Protocol (RTP) and RTP Control Protocol (RTCP) Packets over Connection-Oriented Transport	Media	http://tools.ietf.org/html/rfc4571
RFC 4574	The Session Description Protocol (SDP) Label Attribute	Conferencing	http://tools.ietf.org/html/rfc4574
RFC 4575	A Session Initiation Protocol (SIP) Event Package for Conference State	Conferencing	http://tools.ietf.org/html/rfc4575
RFC 4733	RTP Payload for DTMF Digits, Telephony Tones and Telephony Signals	Telephony	http://tools.ietf.org/html/rfc4733
RFC 5139	Revised Civic Location Format for Presence Information Data Format Location Object (PIDF-LO)	e911	http://tools.ietf.org/html/rfc5139
RFC 5245	Interactive Connectivity Establishment (ICE)	Media	http://tools.ietf.org/html/rfc5245
RFC 5280	Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile	Security	http://tools.ietf.org/html/rfc5280
RFC 5389	Session Traversal Utilities for NAT (STUN)	Media	http://tools.ietf.org/html/rfc5389
RFC 5652	Cryptographic Message Syntax (CMS)	Security	http://tools.ietf.org/html/rfc5652
RFC 5766	Traversal Using Relays around NAT (TURN)	Media	http://tools.ietf.org/html/rfc5766
RFC 6797	HTTP Strict Transport Security (HSTS)	Security	http://tools.ietf.org/html/rfc6797

Lync Normalization Rules, RCC and You

A little publicized feature of Lync is its ability to remotely control a deskphone from another vendor (say Cisco).  This is known as Remote Call Control (RCC).  Your desk phone rings, and you get the Lync pop-up telling you about the call. Clicking the pop-up will answer the call on your deskphone.  You can make calls via Lync, but the call will be dialed via your deskphone.  In this scenario, you're not using any of the features of Enterprise Voice, but it does provide some semblance of integration between another vendor's PBX and Lync.  The mechanism that allows this coordination is called Computer Supported Telecommunications Application (CSTA).  If the PBX doesn't support it natively, then you would usually deploy a SIP/CSTA gateway between Lync and the PBX.

This post isn't about how to setup RCC.  There is already lots of information out there about that.  As the post title infers, it's about phone number normalization and RCC and some confusing information from Microsoft. 

If you read through the official Technet documentation on RCC, you may have noticed the following bit of info (from http://technet.microsoft.com/en-us/library/gg558630.aspx):

Lync clients download phone number normalization rules as part of the Address Book Service (ABS) file download. In remote call control scenarios, Address Book Service phone number normalization rules are applied to both incoming and outgoing remote call control calls.

From that, you'll probably think that all you need to do is to setup normalization rules as part of a Lync dial plan, as I've described before.  So, you go through the motions of creating a dial plan, but you'll soon realize that the normalization rules you created are not being applied to RCC calls.  If you do some more digging, you might come across this seemingly contradictory statement from Microsoft (from Remote Call Control Features not Working):

Issue: You are using remote call control with Microsoft Lync 2010 and are unable to do one or more of the following:

• Download normalization rules (emphasis mine)
• Use video calling
• Transfer meetings to your own number(s)
• Join meetings by using the Join From dialog box

Resolution: Lync 2010 does not support the remote call control features in the preceding list. There currently is no workaround for this issue.

While these two statements might seem to contradict each other, they are actually both correct.  The key difference is that the first statement says Lync will download normalization rules as part of the Address Book Service file download.  The documentation doesn't go into much more detail on that, but what they are referring to is the normalization rules stored in the Company_Phone_Number_Normalization_Rules.txt file. 

The original purpose of this file was to store normalization rules that are applied to phone numbers associated with Active Directory user accounts. If your users' phone numbers in AD are not in E.164 format, then Lync won't show them to you when you click on a user.  The normalization rules defined in the Company_Phone_Number_Normalization_Rules.txt file are used to normalize those AD numbers into the proper E.164 format.  I won't go into more detail, because there is already an excellent post on the subject by Jeff Schertz. 

The little known part is that this same file is the ONLY method used for normalizing phone numbers  typed into the Lync client for outbound dialing, when that user is enabled for RCC.  Lync dial plan normalization rules are not applied (hence the statement about RCC Lync users not downloading normalization rules). 

For instance, if your PBX requires a 9 in front of local numbers and an 8 in front of long-distance numbers, you would have to create these rules in the Company_Phone_Number_Normalization_Rules.txt file like this:

^(\d{10})$
9$1

^(1\d{10})$
8($1)

When a user types a 10-digit number into Lync like 4165551111, it will normalize to 94165551111, which can be sent to the PBX for proper remote call control functionality.  Likewise, typing 16132223333 would normalize to 816132223333

An additional example would be 4-digit extensions that need to be translated to 10-digits:

^(\d{4})$
905222$1

You may notice that these examples don't normalize to E.164, which is something I preach regularily on this blog.  When you're dealing with a legacy PBX, you're at the mercy of whatever rules are defined for it.  Those rules often don't use E.164 formatting.  You just have to work with what you've got.

Now, what if you've got multiple sites that you want to use RCC, but each site has its own special rules on how to deal with particular numbers?  You can have a different Company_Phone_Number_Normalization_Rules.txt for each Lync pool, so it shouldn't be too difficult to make RCC work in most scenarios.

In essense, when deploying RCC, don't bother creating Lync dial plans, normalization rules or any other Enterprise Voice related content.  Remote Call Control simply does not use any Enterprise Voice functionality.  The Company_Phone_Number_Normalization_Rules.txt file is the only way to do any number manipulation.

Hopefully, this will help anyone attempting to deploy Lync RCC and has come across this stumbling block.

Lync Desktop Sharing UI Issue

I love the Lync client (I also love lamp).  It's a slick, easy-to-use application that handles, IM, voice, video, conferencing, whiteboarding and desktop sharing.  But like everything in life, you've got to take the good with the bad.  The bad things in Lync are really more minor annoyances to me, but when I see them trip up users over and over again (myself included), I think "there's got to be a better way to do this".  I'm a stickler for a well-designed user interface, so when I see something missing, it gets on my nerves a bit.

The thing I'm talking about today is related to desktop/application sharing.  UI-wise, it works like a charm in most cases, but there's a scenario that more often than not, confuses the hell out of people.  Let me take you through it:

You start a desktop sharing session with one of your colleagues.  You easily find the Sharing button in the Lync client and click Share desktop.

You share your desktop, and everything is great.  You'll notice a yellow bar notifying you that you're sharing your screen. 

If you click the Preview button, it will open the "stage" which shows you what other people are seeing. The stage will show you one of those cool things that happens when you have 2 mirrors opposite each other....the scene just keeps repeating itself smaller and smaller and smaller until its the size of atoms (or so I imagine).  Normally, you don't want to show your stage, because it just gets in the way, so you click "Hide stage".

Now, the other guy wants to show you something on his desktop, so he shares his desktop out.  He'll get a notification saying his sharing will replace yours..

And your screen sharing session will just go away and you'll see this yellow bar notification.

However, even though the double arrow beside the user sharing is "lit up", you won't see his desktop.  You'll thrash around in confusion until either you quit your job because Lync has "beaten you" or you stumble onto how to see the other person's desktop.  If either of those cases don't apply, I'll share the secret.  You have to click on Share - Show Stage for the other guy's desktop to show up on your screen.

A very simple way out of this little UI conundrum is to add a button on the yellow notification bar to "Show stage".  If the right people see this blog, maybe we'll see it incorporated in a future patch.

Until next time, cheers!