H.225.0 is part of the H.323 family of telecommunication protocols.
The main objective of H.225.0 is the definition of messages and procedures for:
The Message Encoding is performed by utilizing Q.931 User-to-User information elements to convey H.225 messages. The messages themselves are encoded according to the Packed Encoding Rules (PER) of ASN.1.
The structure of H.225 follows the Q.931 standard as seen in the table below.
8
|
7
|
6
|
5
|
4
|
3
|
2
|
1
|
Octet
|
Protocol Discriminator
|
1
|
|||||||
0
|
0
|
0
|
0
|
Length of call reference bits
|
2
|
|||
Call reference value
|
3 (-4) | |||||||
0
|
Message type
|
|
||||||
Information Elements
|
|
|||||||
H.225 structure
|