Identify Frame lenght in FAST UDP packet

himanshuk_x · February 7, 2012, 9:56am

Imported from previous forum

himanshuk_x · February 7, 2012, 9:56am

Hi

I am receiving UDP packet in following manner

How to identify frame length so that I can find size of msg(1)…consequently of msg(2)…msg(3)…

Frame size usually the first byte but it can be up to 4 bytes of uncompressed data received.How to identify when it’s more than 1 byte?

Thanks

Himanshu

fplpo_x · February 8, 2012, 3:58am

[ original email was from janaka Sooriyaarachchi - janakas@millenniumit.com ]

frame size also a integer value, So you can use integer encoding/ decoding method to resolve the value and you can identify the field termination by stop bit.

Hi

I am receiving UDP packet in following manner

|frame size(1)|msg(1)|frame size2|msg(2)|…|frame size(i)|msg(i)|
=================================================================
UDP PACKET N

How to identify frame length so that I can find size of msg(1)…consequently of msg(2)…msg(3)…

Frame size usually the first byte but it can be up to 4 bytes of uncompressed data received.How to identify when it’s more than 1 byte?

Thanks

Himanshu

himanshuk_x · February 8, 2012, 12:55pm

Hi Janaka

Binary feeds received have following value in first four bytes.
What will be stop bit here to find message length here ?

case 1.

Uncompressed binary data received

F1 DE 00 83
11110001 11011110 00000000 10000011

Removing first bit and converting to integer value

1110001 11011110 - 0000011

Integer Value

113 94 3

Case 2

Uncompressed binary data received

01 8B DE 00
00000001 10001011 11011110 00000000

Removing first bit and converting to integer value

```
  0001011		1011110		-
```

Integer Value

```
  11		94		-
```

frame size also a integer value, So you can use integer encoding/ decoding method to resolve the value and you can identify the field termination by stop bit.

Hi

I am receiving UDP packet in following manner

|frame size(1)|msg(1)|frame size2|msg(2)|…|frame size(i)|msg(i)|
=================================================================
UDP PACKET N

How to identify frame length so that I can find size of msg(1)…consequently of msg(2)…msg(3)…

Frame size usually the first byte but it can be up to 4 bytes of uncompressed data received.How to identify when it’s more than 1 byte?

Thanks

Himanshu

fplpo_x · February 9, 2012, 2:52am

[ original email was from janaka Sooriyaarachchi - janakas@millenniumit.com ]
Hi,

In the Case 1,
Very first bit also have a stop bit.
So your message length is 113. That contains in a single byte

But in case 2,
you need to take 2 bytes,

00000001 10001011

After removing stop bits,
0000001 0001011

Then convert that value to decimal
00000010001011 = 139

now your message length is 139.

Hi Janaka

Binary feeds received have following value in first four bytes.
What will be stop bit here to find message length here ?

case 1.

Uncompressed binary data received

F1 DE 00 83
11110001 11011110 00000000 10000011

Removing first bit and converting to integer value

1110001 11011110 - 0000011

Integer Value

113 94 3

Case 2

Uncompressed binary data received

01 8B DE 00
00000001 10001011 11011110 00000000

Removing first bit and converting to integer value
0001011		1011110		-
Integer Value
11		94		-
frame size also a integer value, So you can use integer encoding/ decoding method to resolve the value and you can identify the field termination by stop bit.

Hi

I am receiving UDP packet in following manner

|frame size(1)|msg(1)|frame size2|msg(2)|…|frame size(i)|msg(i)|
=================================================================
UDP PACKET N

How to identify frame length so that I can find size of msg(1)…consequently of msg(2)…msg(3)…

Frame size usually the first byte but it can be up to 4 bytes of uncompressed data received.How to identify when it’s more than 1 byte?

Thanks

Himanshu

himanshuk_x · February 9, 2012, 11:50am

It’s working now…

Thanks Janaka for valuable help…

Hi,

In the Case 1,
Very first bit also have a stop bit.
So your message length is 113. That contains in a single byte

But in case 2,
you need to take 2 bytes,

00000001 10001011

After removing stop bits,
0000001 0001011

Then convert that value to decimal
00000010001011 = 139

now your message length is 139.
Hi Janaka

Binary feeds received have following value in first four bytes.
What will be stop bit here to find message length here ?

case 1.

Uncompressed binary data received

F1 DE 00 83
11110001 11011110 00000000 10000011

Removing first bit and converting to integer value

1110001 11011110 - 0000011

Integer Value

113 94 3

Case 2

Uncompressed binary data received

01 8B DE 00
00000001 10001011 11011110 00000000

Removing first bit and converting to integer value
0001011		1011110		-
Integer Value
11		94		-
frame size also a integer value, So you can use integer encoding/ decoding method to resolve the value and you can identify the field termination by stop bit.

Hi

I am receiving UDP packet in following manner

|frame size(1)|msg(1)|frame size2|msg(2)|…|frame size(i)|msg(i)|
=================================================================
UDP PACKET N

How to identify frame length so that I can find size of msg(1)…consequently of msg(2)…msg(3)…

Frame size usually the first byte but it can be up to 4 bytes of uncompressed data received.How to identify when it’s more than 1 byte?

Thanks

Himanshu

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Identify Frame lenght in FAST UDP packet

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