Page 167 - DCAP207_NETWORKS_DCAP406_COMPUTER_NETWORKS

Computer Networks/Networks

Notes exceeding this limit is not considered. However, in integrated service, any packet overruling
the packet size is not limited but discarded and will not be allowed for a RSVP connection
request. The maximum token bucket size is considered as 1 GB.
Token Rate Limit: The rate limit is the number of bits per second that can be allowed into a
network. The requested bandwidth for an application is compared with the token rate limit.
When the requested bandwidth is more than the rate limit, the request is denied. The token rate
limit is only used for admission control within integrated service. This value can range from
10 Kbps to 1 Gbps.

Self Assessment

State whether the following statements are true or False:
6. The quality of service (QoS) of computer networks is evaluated with respect to the traffic
priority.
7. Bandwidth has no role to plays in providing a good quality of service.
8. The best effort traffic model handles all Internet requests with equal priority and serves
them with the first come first serve strategy.
9. The congestion management tool may include priority queuing, custom queuing, weighted
fair queuing, etc.

10. The link fragmentation and interleave process segment small packet into large packets
interleaving the voice packet.
11. Shaping is used to prevent the overflow problem in buffers by limiting the full bandwidth
potential of the packets of applications.

10.4 Summary

 IPv4 addresses are uniquely used as identifiers, which work at network layer to identify
the source or destination of IP packets. Presently, the version of IP, which is in use, is called
as IPv4. In this version, every node on Internet may have one or more interfaces, and we
are required to identify each of these devices with a unique address assigned to each of
them. It means that each node is assigned one or more IP addresses to invoke TCP/IP.
These are logical addresses and have 32 bits.
 The designers of the internet protocol defined an ip address as a 32-bit number and this
system, known as internet protocol version 4 (ipv4), is still in use today. However, due to
the enormous growth of the internet and the predicted depletion of available addresses, a
new addressing system (ipv6), using 128 bits for the address.
 When too many packets are present in a part of the subnet, the performance of the subnet
degrades. Hence, a communication channel of a network is called congested if packets
traversing the path experience delays largely in excess of the paths propagation delay. It
is called heavily congested when the packets never reach the destination indicating that
the delay approaches infinity.
 Congestion control and flow control are two different phenomenon. Congestion is a
global phenomenon involving all hosts, all routers, the store-and-forward processing
within the routers, etc., whereas, flow control is concerned with point-to-point traffic
between a given source host and a given destination host.
 According to control theory, the computer network, which is also a system, is divided into
two groups. They are open loop and closed loop solutions.

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