The code points from the DiffServ field can be evaluated by Firewall rules for further control of QoS parameters such as minimum bandwidth or PMTU reduction.
According to your selection of the DSCP type (BE, CS, AF, EF) the valid values can be adjusted in additional drop down lists. Alternatively, the DSCP decimal value can be entered directly. A table listing valid values can be found under .
LANconfig: Firewall/QoS / Rules / Filter rules / Quality of Service
WEBconfig: Setup / IP router / Firewall E Rule list
The Firewall rule is extended by condition “@d” and the DSCP (Differentiated Services Code Point). The code point can either be indicated with its name (CS0 - CS7, AF11 to AF 43, EF or BE) or its decimal resp. hexadecimal depiction. “Expedited Forwarding” can therefore be indicated as “@dEF”, “@d46” or “@d0x2e”. Furthermore, collective names (CSx resp. AFxx) are possible.
Examples:
- %Lcds0 @dAFxx %A: Accept (secured transmission) on DiffServ “AF”, limit “0”
- %Qcds32 @dEF: Minimum bandwidth for DiffServ “EF” of 32 kbps
- %Fprw256 @dEF: PMTU reduction for reception for DiffServ “EF” to 256 bytes
These examples reserve a desired bandwidth for Voice over IP phone calls. The first element “%Lcds0 @dAFxx %A“ accepts DSCP “AFxx” marked packets of signalling calls. Voice data marked with “EF” is transferred preferentially by the entry “%Qcds32 @dEF“, and a bandwidth of 32 Kbps is guaranteed thereby as well. In parallel, the PMTU is reduced to 256 byte by “%Fprw256 @dEF“, which enables ensuring the required bandwidth in receiving direction at all.