There is no section 22.2.2 in rfc 3261. I believe 26.2.2 is what was meant:

Note that in the SIPS URI scheme, transport is independent of TLS,
      and thus "sips:alice@atlanta.com;transport=tcp" and
      "sips:alice@atlanta.com;transport=sctp" are both valid (although
      note that UDP is not a valid transport for SIPS).  The use of
      "transport=tls" has consequently been deprecated, partly because
      it was specific to a single hop of the request.  This is a change
      since RFC 2543.


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@166731 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -117,7 +117,7 @@
  *       specially to communication with other peers (proxies).
  * \todo We need to test TCP sessions with SIP proxies and in regards
  *       to the SIP outbound specs.
- * \todo transport=tls was deprecated in RFC3261 and should not be used at all. See section 22.2.2.
+ * \todo ;transport=tls was deprecated in RFC3261 and should not be used at all. See section 26.2.2.
  *
  * \todo If the message is smaller than the given Content-length, the request should get a 400 Bad request
  *       message. If it's a response, it should be dropped. (RFC 3261, Section 18.3)