The default value 0x10 (010000) corresponds DSCP CS2 (OAM). So, if your routing gear is configured in some way, set the TOS value so that it does what it is supposed to do, regardless of what any RFC says. However, always keep in mind that the 'good' setting for this value depends on how your routing equipment (which needs to interpret it correctly) interprets it. DSCP EF (see above), you would set the TOS field to 0xb8 (DSCP=101110 and ECN=00), as the DS field according to RFC 2475 is put into the IPv4 header TOS octet. So the lower 6 bits of the IPv4 TOS field are used to store the DSCP.Īt the end of the day, if you want to have RTP traffic sent with e.g. Six bits of the DS field are used as a codepoint (DSCP). Intended to supersede the existing definitions of the IPv4 TOS octet So how does the DSCPs binary value maps to the IP TOS header field then?Ī replacement header field, called the DS field, is defined, which is For VoIP traffic, there are:Īs we (currently ) only tag RTP traffic with the TOS value configured, EF(Expedited Forwarding) would be an appropriate DSCP. RFC 4594 defines a number of so-called 'DiffServ codepoint (DSCP)' values and also suggest certain DCSPs to be used for certain applications. RFC 791, RFC 795 and RFC 1349 describe previous and deprecated interpretations. RFC 4594 defines service classes and their intended usage. RFC 2474 and RFC 2475 define the current understanding. Historically, this is due to several changes in the corresponding RFCs that describe the correct interpretation. There is a certain degree of confusion regarding the correct setting of this value. Instead, routing equipment within the network infrastructure is expected to interpret this value. innovaphone devices will not impose any sort of interpretation on this value (except that traffic flowing through one of the PPP interfaces is subject to prioritization if its TOS field exactly matches the configured value). The configured value directly maps to the the header field. The innovaphone devices allow you to specify the IP v4 TOS header field value used for media (i.e. This article discusses what 'appropriate' shall mean. This is normally done by setting the IP TOS header field to an appropriate value.

When voice traffic shall be prioritized by routing equipments in the network, it usually needs to be marked as somehow 'special', so that the routing equipments knows that it needs to perform prioritization. This information applies to all innovaphone devices, V5 and V6

Diff serv sip definition