Information Technology Reference
In-Depth Information
Algorithml: Table lookup message processing.
Input: H.245 ASN.1 messages
m
Output: binary stream
B
(
m
)
1. Initialize system
2. Pre-compile a message set
M
(
m
) and store into a table
T
(
m
)
3. For each
i
th message H.245 ASN.1 message
m
i
4. If
m
i
∋
M
(
m
) then
5. Retrieve bit stream B(
m
i
) from table T(
m
i
)
6. If replacement needed then
7. Replace changed filed(s) and return
8.
Else
return the bit stream
9.
Else
dynamically compile it and store it into table
T
(
m
)
10.End for
11.Repeat step 3 to 10
Figure 3.12
Table lookup message processing algorithm. (From Tso, F. P., “WTS” Conference of IEEE, 2008.
With permission.)
H.245
message
H.245
message
compiler
Already pre-
compiled?
No
Yes
Table lookup
Lookup
result
Table
Bitstream
Replace changed
field(s)
Modification
needed?
Yes
If the whole
message
is new
No
Return
Figure 3.13
Table-lookup process flow. (From Tso, F. P., “WTS” Conference of IEEE, 2008. With permission.)
