In: Computer Science
Describe, and critique, one application with regard to its transmission requirements, such as bandwidth, latency, reliable delivery, in-sequence delivery, and jitter. Example applications include:
Choose an application, and evaluate its needs for these requirements.
Propose a way of provisioning an Enterprise LAN so that this application gets the best performance. Do you see areas of possible conflict? Can you think of other parameters to be considered along with the ones mentioned above? These could be any resource or constraint that would affect the behavior of the network.
If you used a reference, please attach the link.
Thank you
Live unicast
video
A Unicast transmission/stream sends IP packets to a single
recipient on a network. A Multicast transmission sends IP packets
to a group of hosts on a network. If the streaming video is to be
distributed to a single destination, then you would start a Unicast
stream by setting the destination IP address and port on the AVN
equal to the destination’s values. If you want to view the stream
at multiple concurrent locations, then you would set the AVN’s
destination IP address to a valid Multicast IP address (224.0.0.0 –
239.255.255.255).
Note that while the Multicast IP address range is from 224.0.0.0 –
239.255.255.255, the first octet (224.xxx.xxx.xxx) is generally
reserved for administration. VSI recommends setting the first octet
to 225 and the remaining three octets to the AVN’s IP address. For
example, if the AVN’s IP address is 192.168.1.53, then set the
destination IP address to 225.168.1.53 for Multicast
streaming.
Since Multicasting is a relatively new technology, some legacy
devices that are part of your network might not support
Multicasting.
Before using the AVN encoder in Multicast streaming mode, check the
functional specifications of your network infrastructure to ensure
that the Multicast stream will not create major traffic on your
network. Verify that your backbone switch supports Internet Group
Messaging Protocol (IGMP) snooping, which allows the core of your
network to ignore the traffic streams that Multicasting may
generate.
For more information on IGMP querying and snooping please refer to
an AVN encoder’s user manual, available on our website by product,
in the chapter titled “Connecting to the Network”.
Unicast
Reliable delivery has been succinctly defined as "Data is accepted
at one end of a link in the same order as was transmitted at the
other end, without loss and without duplicates." This implies four
constraints:
(i) No loss (at least one copy of each PDU is sent)
(ii) No duplication (no more than one copy of each PDU is
sent)
(iii) FIFO delivery (the PDUs are forwarded in the original
order)
(iv) A PDU must be delivered within a reasonable period
For a communications protocol to support reliability, requires that
the protocol identifies each individual PDUs that is transmitted.
The protocol implements an error recovery procedure (e.g. Stop and
Wait ).
There is very little data which is so important that it must be
sent no matter how late. If the links in the network are therefore
liable may lead to loss of packets, a reliable protocol should be
used. When the under-lying network is very reliable (as in an
Ethernet LAN), best effort protocols may be sufficient.
Reliability may be provided at various levels of the OSI reference
model. Examples of reliable communications protocols are:
Link Layer - (e.g. HDLC ABM)
Transport Layer - TCP
Application Layer (e.g. TFTP)
Layered protocols usually also employ timers at each level,
governing this interval. The service provided by a protocol layer
may be unreliable for various reasons including:
Corruption of bits within the physical medium or the interface to
the physical media.
Faulty bit-timing resulting in erroneous decoding of the value of a
received bit.
A software error within the software used to implement the
communications protocol.
Insufficient buffer space within the communications
equipment.
A "Best Effort" service is one which does not provide full
reliability. It usually performs some error control (e.g.
discarding all frames which may have been corrupted) and may also
provided some (limited) retransmission (e.g. CSMA/CD). The
delivered data is not however guaranteed. A best effort service,
normally requires reliability to be provided by a higher layer
protocol.
Examples of best effort services are:
Link Layer - HDLC (UI frames); Ethernet
Network Layer - IP (Datagrams)
Transport Layer - UDP and UDP-Lite.
Services may be better than best effort, for example provide
service guarentees or better expectations of the service. The
Differentiated Services (diffserv) and Integrated Services
(intserv) frameworks provide this type of service at the
network-layer.
There has also been work on less than best effort services,
specifically services that are designed to operate in the
background. The IP Scavenger service is an example network-layer
service that allows file transfers to safely operate in the
background without impacting other network users. This service has
as yet not been widely used.