Adding documentation for link object
Change-Id: Ied40e45296fb25b7efd227e2e13a2af48223ba1b
diff --git a/interest.rst b/interest.rst
index a6d7460..fa5de11 100644
--- a/interest.rst
+++ b/interest.rst
@@ -12,6 +12,8 @@
Selectors?
Nonce
InterestLifetime?
+ Link?
+ SelectedDelegation?
``Name`` and ``Nonce`` are the only two required elements in an Interest packet.
Selectors are optional elements that further qualify Data that may match the Interest.
@@ -172,3 +174,28 @@
It is the application that sets the value for ``InterestLifetime``.
If the ``InterestLifetime`` element is omitted, a default value of 4 seconds is used (4000).
The missing element may be added before forwarding.
+
+Link
+~~~~
+
+The format is the following::
+
+ Link ::= LinkObject
+
+``LinkObject`` is a :ref:`Data packet <data>` of a dedicated ``LINK`` type and specially-formatted content part, listing a set of delegations (name prefixes and the associated priorities) that should be used to guide forwarding of the Internet packet.
+
+See the :ref:`link` section for formal definition of the ``LinkObject``.
+
+Selected Delegation
+~~~~~~~~~~~~~~~~~~~
+
+The SelectedDelegation field indicates the index of the delegation in the attached ``Link`` that was chosen by a downstream forwarder(s).
+
+The format is the following::
+
+ SelectedDelegation ::= SELECTED-DELEGATION-TYPE TLV-LENGTH
+ nonNegativeInteger
+
+If ``Link`` field is not present, the ``SelectedDelegation`` field MUST NOT be present.
+
+The index value of the ``SelectedDelegation`` field MUST be less than the number of delegations within the ``Link``.