DSCP and IP Precedence represent a view of the same field within the IP Header. CoS is an 802.1p field in ethernet (L2) extend has to do with a connected device. DSCP covers the ToS field in IP. DSCP has names for things that overlap the IP Precedence markings. IP Prec was 3 bits. DSCP is 6 bits, which includes the 3 bits from IP Prec.

Oct 11, 2012 · The DSCP is superior to CoS in most ways - it is retained end-to-end, has a finer granularity, can be easily used both by end hosts and intermediary devices, and is an integral part of. IP header. That makes it the preferred place of …

Mar 16, 2009 · DSCP is a 6 bit field, the DSCP byte takes the place of the older TOS byte. IP precedence bits are only 3 the most meaningful (= leftmost) in the TOS byte definition. A class selector has set the first 3 bits in an attempt to be backward compatible with IP prec.

For Cisco endpoints this is accomplished through the configurable Unified CM QoS service parameters DSCP for Video calls and DSCP for TelePresence calls. When a Cisco TelePresence endpoint registers with Unified CM, it downloads a configuration file and applies the QoS setting of DSCP for TelePresence calls .

the takeaway is the 3 bit shift right repurposing those from tos for dscp, keeping the first 3 aligned for compatibility with Cos, Ip prec, tos and now dscp as in the above diagram... 2 to the 6th or 0 to 63 or 64 total or 000 000 to 111 111 or 32 16 8 4 2 1

Jun 22, 2009 · This table compares QoS values for IP precedence, Differentiated Services Code Point (DSCP) and Multiprotocol Label Switching (MPLS) Experimental (EXP) values along with standard values used in Cisco IOS Software for configuration. For an introduction to this topic, refer to QoS for VoIP.

在有线方面，思科路由器和交换机可以在第3 层上使用dscp 标记或在第2 层上使用cos 标 记。思科无线控制器不进行dscp 标记，而是依靠cos 标记（avc 除外）。这些cos 标记位 于802.1p/q标记中被添加到数据包。802.1q标记为16 位长，12 位用于vlan id（从0到4095），

To remark dscp to another dscp you would use a dscp-mutation. In my situation my router was generating EIGRP hello packets (default dscp48) and I needed to remark them to cos 4 so the provider wouldn't drop them. In this circumstance I used a "mls qos map dscp-cos 48 to 4" to modify the eigrp hello's to cos 4.

Apr 7, 2015 · CoS is a layer 2 Trust mode that is not compatible with Dante. Switches prioritize packets using what are called DSCP/Diffserv values. Although Dante packet priority values have been chosen to make it simple to configure QoS with many switches, some switches require special configuration to recognize and prioritize specific DSCP values.

The traffic leaves with the same CoS and DSCP values as it enters. All the traffic, which includes voice, are delivered on the best effort basis. Switch# show mls qos. QoS is disabled. QoS ip packet dscp rewrite is enabled !--- Even though it says QoS ip packet dscp rewrite is enabled, !--- the switch does not alter the DSCP label on the ...