Subject: [Megaco] ds/dscp property

From: Annie Benitez Pelaez <[email-masked]>
Date: Fri, 5 Oct 2007 02:41:12 -0400

Dear H.248 experts,

If you look at the dscp property from the ds package defined by ETSI, I am looking for some guidance in mappin the dscp bits to the actual TOS byte - would you agree with the following example?

ds/dscp=2E be encoded in the TOS:

ds/dscp = 2E

 would be encoded as:

8 9 0 1 2 3 4 5 6
+-+-+-+-+-+-+-+-+
|1 0 1 1 1 0 x x|
+-+-+-+-+-+-+-+-+
 Type of Service

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Ver= 4 |IHL= 5 |Type of Service|        Total Length = 21      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      Identification = 111     |Flg=0|   Fragment Offset = 0   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Time = 123  |  Protocol = 1 |        header checksum        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                         source address                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                      destination address                      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     data      |
   +-+-+-+-+-+-+-+-+

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---

From: "Schwarz Albrecht" <[email-masked]>
Date: Fri, 5 Oct 2007 11:56:13 +0200

Hi Annie,
 
there are guidelines in the latest draft of ds v1.
-Albrecht
=>
 
http://ftp3.itu.int/av-arch/avc-site/2005-2008/0706_Gen/H248_52_output.zip

7.6.2             Specifics with regards to IP versions and ToS/DS octets

7.6.3             Encoding of ds/dscp property - Examples

________________________________

	From: Annie Benitez Pelaez [mailto:[email-masked]] 
	Sent: Freitag, 5. Oktober 2007 08:41
	To: [email-masked]
	Subject: [Megaco] ds/dscp property

	Dear H.248 experts,

	 
	ds/dscp = 2E

	 would be encoded as:

	8 9 0 1 2 3 4 5 6 

	+-+-+-+-+-+-+-+-+

	|1 0 1 1 1 0 x x|       

	+-+-+-+-+-+-+-+-+

	 Type of Service

	    0                   1                   2                   3   

	   |                         source address                        |

	   |                      destination address                      |

	   |     data      |                                                

	   +-+-+-+-+-+-+-+-+

---

From: Ashish Singh <[email-masked]>
Date: Fri, 05 Oct 2007 11:16:44 -0700

Hi Annie,

If you see the section "B.3 Hexadecimal octet coding", binary digits are 
encoded in reverse order. So if you want to really send"101110xx" in TOS 
Byte field, then you should send ds/dscp = 74

Hope it clarifies.

    -Ashish

Annie Benitez Pelaez wrote:
> Dear H.248 experts,
> If you look at the dscp property from the ds package defined by ETSI, 
> I am looking for some guidance in mappin the dscp bits to the actual 
> TOS byte - would you agree with the following example?
> |Ver= 4 |IHL= 5 |*Type of Service*| Total Length = 21 |
>
> _ _
> ------------------------------------------------------------------------
>