TCP/IP Tutorial and Technical Overview - IBM Redbooks

The RSVP objects that follow the common header consist of a 32-bit header and
one or more 32-bit words. Figure 8-10 shows the RSVP object header.
Figure 8-10 RSVP object header
Where:
0 16 24 31
Length (Bytes) Class - Number C-Type
(Object Contents)
Length 16-bit field that contains the object length in bytes. This
must be a multiple of 4. The minimum length is 4 bytes.
Class-Number Identifies the object class. The following classes are
defined:
NULL The NULL object has a Class-Number of zero. The
length of this object must be at least 4, but can be any
multiple of 4. The NULL object can appear anywhere
in the object sequence of an RSVP message. The
content is ignored by the receiver.
Session The Session object contains the IP destination
address, the IP protocol ID, and the destination port to
define a specific session for the other objects that
follow. The Session object is required in every RSVP
message.
RSVP_HOP The RSVP_HOP object contains the IP address of the
node that sent this message and a logical outgoing
interface handle. For downstream messages (for
example, path messages), the RSVP_HOP object
represents a PHOP (previous hop) object, and for
upstream messages (for example, Resv messages), it
represents an NHOP (next hop) object.
Time_Values The Time_Values object contains the refresh period
for path and reservation messages. If these messages
are not refreshed within the specified time period, the
path or reservation state is canceled.
Chapter 8. Quality of service 305