Which attribute can be used to identify the streaming video flow?

You want to prioritize the video streaming traffic over the HTTP server traffic. Which attribute can
be used to identify the streaming video flow?

A.
the NIC Transmit and Receive Ring

B.
the Differentiated Service Field

C.
the Application Port Number

D.
IP address and TCP port

Explanation:
* DiffServ uses the 6-bit Differentiated services Field (DS field) in the IP header for
packet classification purposes.
* In the Diffserv model, the marker marks a packet with a value that reflects a forwarding behavior.
Marking is the process of placing a value in the packet’s header to indicate how to forward the
packet to the network. IPQoS contains two marker modules:
/ dscpmk – Marks the DS field in an IP packet header with a numeric value that is called the
Differentiated Services codepoint, or DSCP. A Diffserv-aware router can then use the DS
codepoint to apply the appropriate forwarding behavior to the packet.
/ dlcosmk – Marks the virtual local area network (VLAN) tag of an Ethernet frame header with a
numeric value that is called the user priority. The user priority indicates the class of service (CoS),
which defines the appropriate forwarding behavior to be applied to the datagram.
Note:
* Differentiated services or DiffServ is a computer networking architecture that specifies a simple,
scalable and coarse-grained mechanism for classifying and managing network traffic and
providing quality of service (QoS) on modern IP networks. DiffServ can, for example, be used to
provide low-latency to critical network traffic such as voice or streaming media while providing
simple best-effort service to non-critical services such as web traffic or file transfers.
* IPQoS, included in Solaris, includes the following modules, which are part of the Differentiated
Services (Diffserv) architecture that is defined in RFC 2475:
Classifier
Meter

Marker
IPQoS adds the following enhancements to the Diffserv model:
Flow-accounting module
802.1D datagram marker