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© 2014, IJARCSSE All Rights Reserved Page | 648
Volume 4, Issue 8, August 2014 ISSN: 2277 128X
International Journal of Advanced Research in Computer Science and Software Engineering Research Paper Available online at: www.ijarcsse.com
Implementation of Modified TIMIP for overlay Networks with
Enhanced Handover and QoS
Amit Nain* Sapna
Sudesh Kumar
BRCM CET Behal-Bhiwani, BRCM CET Behal-Bhiwani, BRCM CET Behal-Bhiwani,
India India India
Abstract—The goal of this paper is to propose and implement the modified terminal independent mobile internet
protocol that provides enhanced Quality of Service (QoS).The generic architecture of mobile Internet protocols doesn’t
support various IP versions, legacy terminals and routers. This paper describes the identification of problem areas
within the general mobility protocols. Transparency defines the protocol compatibility with the pre-legacy infrastructure.
Secondly, efficiency deals with the smooth and fast handover and low overhead services. Modified TIMIP is designed
first and then it shows how well the protocol can handle various traffic like TCP, UDP,best effort with
guaranteed QoS, even for mobility unaware networks. At last, the comparisons have been made among the various
mobility protocols which show how well the proposed solution provides the various improvements over the rest available
protocols.
Keywords—Quality of Services, Modified TIMIP, Legacy Infrastructure Support, Seamless Handover.
I. INTRODUCTION
The aim of this work is performance evaluation study of the various mobility solutions and based on the various features
combination, implementation of an optimum protocol. This comparison can incorporate a number of factors [1] such as:
average number of forwarded control packets per MN handover; absolute number of forwarded data packets by GW;
Absolute maximum number of buffered packets in all mobility queues per handover; UDP services metrics such as Drop
ratio, out of order ratio, Total losses ratio, UDP throughput ratio, one way delay, Handover latency. TCP services metrics
such as TCP Throughput ratio, Overhead ratio, Congestion window etc. In this paper some problems of terminal
independence would be investigated. The main focus of research would be on:
1) To propose modified TIMIP for overlay network design to enable efficiency and transparency gains.
2) To provide the best alternative solutions, by featuring fast handovers, paging, tree-optimal routing and resource
optimization techniques.
3) To compare the various protocols based on the various performance metrics.
Legacy Networks & Terminals
A legacy network [2] refers to a network that is not based on the IP (TCP/IP) protocol. IPX, SNA, AppleTalk and
DECnet are examples of legacy networks. The legacy terminals define the terminals which are not having support for
communication.
with the mobile systems. In a wireless world, it is the need of today to make all IP networks that would be compatible for
all type of terminals, for all IP protocol router communication without the changes in the underlay network topology.
1. Various Mobile IP Protocols
MIP
The protocol considers that hosts are reached using two global complementary addresses, to solve the classical
“identifier” vs. “locator” problem that IP addresses have [3-4].The Home Address is a unique IP address used by the
correspondent nodes to contact the MN in all locations, serving as a constant identifier; the CareOf address is a second IP
address that reflects the actual MN’s localization in the visited networks, changing each time it moves between networks
and being used by MIP as a temporary MN locator [4]. Thus, the main objective of the MIP protocol is to redirect the
packets received in the Home Network to the current Visited Network, by keeping the MN’s CareOf Address updated as
the MN moves between networks. hMIP
A recent MIPv4 extension called hierarchical MIP (hMIP)[11]was proposed to extend the MIPv4 protocol with micro-
mobility capabilities, enabling faster handovers and better scalability. For this, the single HA-FA tunnel is extended to a
hierarchy of FAs and the MNs will manage multiple hierarchical CareOf addresses, one per hierarchical level. CIPv4/v6
The Cellular IP (CIP) [5] protocol was one of the first approaches to provide a mobility support more efficient than the
one provided by MIP, complementing it in an independent way. This protocol is based on fairly different principles than
MIP, being limited to single IP domains, and having the network elements organized on a strict tree structure topology
(e.g., no support for pre-existing topologies and legacy routers is available).However this protocol provides support for
the micro mobility. Inside the tree, the nodes contain direct soft-state routing entries that reference only the next hop that is
Nain et al., International Journal of Advanced Research in Computer Science and Software Engineering 4(8),
August - 2014, pp. 648-658
© 2014, IJARCSSE All Rights Reserved Page | 649
closer to the terminal; thus, this routing chain is able to identify the MN’s location inside the network. At the top of the tree,
a special Gateway (GW) node contains routing entries for all network’s MNs, being also the unique point of attachment
to the outside (thus excluding multiple additional border routers). At the tree leaves, the APs provide connectivity to the
MNs, emitting special CIP beacons to the wireless medium.
HAWAII
The Handoff-Aware Wireless Access Internet Infrastructure protocol is an alternative proposal that transparently extends
MIP with micro-mobility support. An important difference from CIP is that the terminals are only required to implement
a modified MIP client, as the protocol provides micro-mobility transparently. HAWAII is transparent to mobile IP. A
mobile node moving in a HAWAII-administered domain will not need to change its COA, and no communication with
the home agent is required. Two special signaling packets are introduced, power-up update and handoff update [6]. For
this, a similar division of domains and hierarchy of nodes are established, forming a logical tree with a Root Gateway
taking as the sole point of attachment to the outside, which again precludes support for multiple mobile-aware border
routers. The tree leaves contain the APs, which implement a MIP compatible interface to the wireless interface on the
form of a FA. Although HAWAII forces a node tree structure for the arrangement of the routers, it may use extra links
between the nodes to create the mobile paths TIMIP/sMIP
The TIMIP protocol was proposed to give efficient mobility support to all existing terminals in micro-mobility contexts,
by introducing a terminal independent mobility architecture feature. This model, originally proposed in reference,
identified the key mobility operations that must be performed by the network in order to achieve this independence. Thus,
the network is the sole responsible for the mobility actions that are typically executed by the terminals while roaming,
implementing a “surrogate behavior”, which was defined originally in reference. Using this feature, TIMIP can support
any terminal, and thus does not impose the client migration cycle that MIP and other protocols require. Unlike other
proposals, TIMIP featured strong LMN support from its base, as it only uses mechanisms that do not imply modifications
to the terminals. [7-8]
Modified TIMIP
The MTIMIP protocol is proposed to fill the missing features [9] of the various TIMIP extensions, such as routing caches,
efficiency transparency trade off, idle terminal support. TCP throughput degradation in TIMIP extension due to the
incorrect delivery of in flight packet has also been improved. MTIMIP routing handover is able to achieve an even more
efficient data routing service, due to the fact that it is able to send the packets between the domain’s agents directly. Such
optimal routing scheme, which is only supported earlier by the macro-mobility’s MIP protocol, could be used to further
lower the end-to-end delay. It decouple the data and control paths, by enabling the bypass of data traffic through the
single GW in inter-domain traffic scenarios, providing load balancing. It divides the cell area into various paging areas,
which reduces the location updates and saves battery life time. Only authenticated packets can establish or change cache
mappings in a MTIMIP access network. The Authentication, Encryption combination has been provided through the
HMAC-MD5, DES algorithms.
HMAC-MD5[10], DES provides the optimum security while preserving the various networking parameters optimum[10-
11].
II. SIMULATION ENVIRONMENT
Figure 2 shows the chosen simulation scenario that represents an Internet domain organized according to cellular
principles. In this, mobile nodes will roam inside the network, being connected to it using IEEE 802.11 wireless links.
The fixed part of the network (backbone) is constituted by a hierarchy of nodes, connected by wired Ethernet links
forming a mesh or tree topology.
Nain et al., International Journal of Advanced Research in Computer Science and Software Engineering 4(8),
August - 2014, pp. 648-658
© 2014, IJARCSSE All Rights Reserved Page | 650
The scenario features 8 NS2 Base Stations that share the capabilities of ARs and APs – i.e., they have both Layer 2 and
Layer 3 capabilities. Each one of them will manage an independent 1 Mbit/s IEEE 802.11 cell with different frequencies.
Thus, hard L2 handovers will be emulated, as thestations will only be able to receive data packets via one AP at a time.
The ARs are interconnected to the single GW by a series of agents, organized in a hierarchical tree structure of point-to-
point wired links of 10 Mbit/s and sufficient buffer space to force queuing instead of packet dropping. The topology
features extra redundant links that are required for testing the reliability against link failures, and the efficiency gains that
some protocols may provide. All internal links feature the same constant delay of 5ms. The simulated backbone links can
be customized by introducing link failures and/or link load, which are used to test the robustness of the protocols. If not
specifically stated, all test sets assume that all internal nodes are mobility-aware by containing mobility agents, in order to
test the maximum possible performance of the protocols. The network features two MNs connected to it: the first (LMN1)
will roam inside the domain, being the receiver of the test traffic, while the second (CN2) will be stationary at the last AR,
being used for generating traffic for intra-domain situations. The first MN will move inside the network at a high speed
(30 handovers/minute), performing back-and-forth movements that cover the whole domain. In these movements, the MN
will connect to each AR in sequence, starting from AR1 to AR8, to return from AR8 back to AR1. In addition, some tests
explore the case of localized movements, where the MN performs the same number of handovers between two adjacent
ARs, and stationary situations, where the MN is stable located at a given AR Finally, the domain also features two access
network gateways (ANGs) to connect to the core networks, which are simulated using links with the higher delay values.
To simulate inter-domain traffic, a wired correspondent node (CN1) is used outside the domain that is directly connected
to the Home Agent and is used to generate test traffic destined to the first MN; the intra-domain traffic is simulated by
entering traffic at the stationary CN2 located at AR8.
Both UDP and TCP traffic types are considered in the performed tests. Regarding the former, the moving MN1 will be
the receiver of a Constant Bit Rate (CBR) test flow of small test packets, of 100 bytes each, at a rate of 200 packets per
second. Besides regular drop detection, the UDP receiver also features out-of-order packet detection capabilities.
Regarding TCP, the MN will also be the receiver of a File Transfer Protocol (FTP) test flow of large packets, of 1500
bytes each, using the standard NS2 TCP Tahoe agent implementation. Both test streams are started long enough before
the MN movements, by means of a warm-up period that stabilizes the scenario before the handover events. For the same
reasons, the optional link failures and link load will start long enough before the handover events.
After this initial warm-up period, the chosen series of simulated movements will be performed, ending with the
calculation of the metrics. To enable a higher level of confidence in the measured metrics, a series of multiple
independent runs is performed. For this, the handover time instants are randomized in such a way that maintains the
desired average MN speed. Besides the handover time instants, the random seed also randomizes other NS2 components,
namely the traffic start instant and the wireless back-off random variables. Thus, each presented metric is taken from the
average of all performed independent runs, coupled with its 95% confidence interval [4].
In the described scenario, the MTIMIP protocol will be compared with the original TIMIP model, and with the alternative
micro-mobility proposals CIP, HAWAII and hMIP and the macro-mobility standard, MIP. From the set of CIMS options,
a sample subset was selected: the CIP hard-handover option, due to the fact that L2 hard-handovers are the ones used in
real 802.11 networks and HAWAII Multiple-Stream-Forwarding (MSF), due to usage of standard routing tables without
interface information, and because the MN is able to listen/transmit to only one base station at one moment. As all
protocols in this group, except HAWAII, have shown to have the exact same results in both tree and redundant meshed
networks, all the results are presented for the Mesh case, and the HAWAII results in specific tree topologies is marked as
HAWAII tree.
Nain et al., International Journal of Advanced Research in Computer Science and Software Engineering 4(8),
August - 2014, pp. 648-658
© 2014, IJARCSSE All Rights Reserved Page | 651
III. IMPLEMENTATION AND RESULTS
The primary objectives of MTIMIP protocol are to provide:
Handover efficiency, Routing efficiency
Transparency support, reliability
Scalability support
There are a total of six tests and six test scripts here:
to the Home Agent and is used to generate test traffic destined to the first MN; the intra-domain traffic is simulated by
entering traffic at the stationary CN2 located at AR8.
Both UDP and TCP traffic types are considered in the performed tests. Regarding the former, the moving MN1 will be
the receiver of a Constant Bit Rate (CBR) test flow of small test packets, of 100 bytes each, at a rate of 200 packets per
second. Besides regular drop detection, the UDP receiver also features out-of-order packet detection capabilities.
Regarding TCP, the MN will also be the receiver of a File Transfer Protocol (FTP) test flow of large packets, of 1500
bytes each, using the standard NS2 TCP Tahoe agent implementation. Both test streams are started long enough before
the MN movements, by means of a warm-up period that stabilizes the scenario before the handover events. For the same
reasons, the optional link failures and link load will start long enough before the handover events.
After this initial warm-up period, the chosen series of simulated movements will be performed, ending with the
calculation of the metrics. To enable a higher level of confidence in the measured metrics, a series of multiple
independent runs is performed. For this, the handover time instants are randomized in such a way that maintains the
desired average MN speed. Besides the handover time instants, the random seed also randomizes other NS2 components,
namely the traffic start instant and the wireless back-off random variables. Thus, each presented metric is taken from the
average of all performed independent runs, coupled with its 95% confidence interval [4].
In the described scenario, the MTIMIP protocol will be compared with the original TIMIP model, and with the
alternative micro-mobility proposals CIP, HAWAII and hMIP and the macro-mobility standard, MIP. From the set of
CIMS options, a sample subset was selected: the CIP hard-handover option, due to the fact that L2 hard-handovers are
the ones used in real 802.11 networks and HAWAII Multiple-Stream-Forwarding (MSF), due to usage of standard
routing tables without interface information, and because the MN is able to listen/transmit to only one base station at one
moment. As all protocols in this group, except HAWAII, have shown to have the exact same results in both tree and
redundant meshed networks, all the results are presented for the Mesh case, and the HAWAII results in specific tree
topologies is marked as HAWAII tree.
IV. IMPLEMENTATION AND RESULTS
The primary objectives of MTIMIP protocol are to provide:
Handover efficiency, Routing efficiency
Transparency support, reliability
Scalability support
There are a total of six tests and six test scripts here:
Cellular IP
Hierarchical MIP
HAWAII
TIMIP
ETIMIP
MTIMIP
Here while comparing the protocols our protocol should be compared to eTIMIP protocol the most enhanced version of the
TIMIP as all other protocols doesn’t provide the various facilities provided by the TIMIP (as transparency and efficiency for
legacy networks) but as we have to compare all other protocols too we have shown them all. The comparison parameters are
classified into three categories to describe the transparency, efficiency, Real time traffic communication compatibility.
Table 1: Comparison of various protocols
Protocol Control
Load
Drop
Ratio
Out of
order
Ratio
TL
R
UDP
Thr..
Ratio
Hand
over
Latency
MTIMIP 4.67 20 0 20 767.3 70.45
ETIMIP 4.67 31 0 31 717.3 113.97
TIMIP 4.67 14 0 14 762.6 57.42
MIP 5 72 0 72 608 245.88
HMIP 5 66 0 66 624 231.80
CIP 5 16 0 16 757.3 64.03
HAWAII 3.67 10 5 15 744 110.5
Nain et al., International Journal of Advanced Research in Computer Science and Software Engineering 4(8),
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© 2014, IJARCSSE All Rights Reserved Page | 652
A. Efficiency Parameters
Fig 3:Protocols Data Drop ratio comparison in highest load scenarios
Above graph indicates the low drop ratio for MTIMIP as compared to the other protocols providing the micro & macro
mobility (ETIMIP, MIP, HMIP) thus providing more reliable communication. Here basically for the performance
comparison we should stick to the eTIMIP protocol, most advanced version of Terminal Independent Mobile IP as other
protocols does not provide the various facilities like CIP and HAWAII protocols work for single IP domain and for low
range multiple IP domain only and can not provide Macro Mobility/Global Mobility so these can’t be compared based on
the same measures. Here, it can be seen that both the handovers and the basic routing service are moderately affected by
small amounts of wired link load, this effect being greatly amplified for the highest amount of link loads. This happens
because, even though the routers have very large queue sizes to try to prevent packet losses, such queuing greatly delays the
handover update, resulting in more packets being forwarded to the previous location where they will be dropped. For this
reason, and by having simpler handover mechanisms, both MTIMIP and CIP show the lowest degradation in the highest
load scenarios.
Figure 4: Discrete value latency comparison of various protocols
Handover Latency =∑ (reception timestamp first packet received via the new AR - reception timestamp last packet received
via the old AR) / number of handovers
It is measured in ms and provides the time units to stabilize the communication from one access router to another access
router. Handover Latency is also being optimized in the case of modified TIMIP protocol thus providing better efficiency.
For soft handoff(seamless handover) MTIMIP gives the optimum values. MTIMIP protocols are represented by blue lined
graphs in this paper.
The MIP protocol presents a scalable solution to wide area mobility, it also suffers from several inefficiencies and other
faults. As all MN movements force a registration at the HA, and are detected with MIP beacons only, long latencies in each
handover are expected which can result in packet losses, additional handover latency and throughput degradation.
Generically, the solution to these problems has been relegated to the macro / micro mobility approach, enabling MIP to
handle the rare inter-domain movements only. Handover efficiency improvements have been achieved in MTIMIP by aiding
the movement detection process with lower-layer triggers, and using local registration processes and buffering techniques
Figure 5: Interdomain Handover Latency comparison
Nain et al., International Journal of Advanced Research in Computer Science and Software Engineering 4(8),
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© 2014, IJARCSSE All Rights Reserved Page | 653
Figure 6: Intra domain handover latency
These comparisons show that the MTIMIP takes minimal time to stabilize the number of received packets and thus
provides minimal handover latency. The blue lines indicate the values for proposed protocol.
Figure 7: The effect of tree optimization over handover latency for MTIMIP protocol
The above graph provides the effect of tree optimization routing over handover latency of MTIMIP as clearly it can be
seen that the treeless routing (blue lined graph)takes lesser stabilization (lesser handover latency interval)time than the
earlier proposed scheme for handover(the hierarchical routing).
Figure 8: UDP Throughput Ratio
Nain et al., International Journal of Advanced Research in Computer Science and Software Engineering 4(8),
August - 2014, pp. 648-658
© 2014, IJARCSSE All Rights Reserved Page | 654
.
Figure 9: TCP Throughput comparison
Above figure shows the throughput comparison for TCP traffic it clearly identifies that the MTIMIP protocol shows the
optimized throughput compared to the eTIMIP. All other protocol comparison is also being shown.
B. Transparency Parameters
Control Load: This is used to show the signaling load for the communication per MN handover. Figure 9 shows the average
control load that the protocols require to instantiate the handovers. All protocols have a similar number of update control
packets forwarding, because all of them use a single update message that is forwarded, on average, 5 times per handover for
all protocols. HAWAII has a slight lower value, as the update packets are sent directly to the previous AR, bypassing the
tree. The new AR stores the values of the (Mobile Host MAC, TR Agent address (the leaf hierarchical Agent required to
reach the new AR)).And through a single update message changes the values in the previous AR.
As MTIMIP only uses a single update message, a low control load is achieved, which is also typically limited to
the lower parts of the domain but it have to reach the cross over node for the handover process
control load
0
1
2
3
4
5
6
MTIMIP ETIMIP TIMIP MIP HMIP CIP HAWAII
protocols
cont
rol l
oad
and The stationary results showed that MTIMIP has the best resource optimization performance for intra-domain traffic,
which is a result of its tree-optimFigure 10: Control load comparison
Gateway Load: This identifies the absolute number of packet forwarded per MN handover. Except the MTIMIP/TIMIP
protocols every other protocol gives the same results, as the same amount of data traffic is always required to pass through
the GW.while in case of MTIMIP and other terminal independent protocols and HAWAII in intra domain case, protocols
send the internal traffic directly in the lowest parts of the tree, without involving the tree. In the case to extract the
information we have used the command:
grep ^r mtimip.tr|grep MAC|grep cbr|grep ^ 0
Gateway Load
580
585
590
595
600
605
610
MTIMIP ETIMIP TIMIP MIP HMIP CIP HAWAII
Protocols
Num
ber o
f pac
kets
/han
dove
r
Figure 11: Gateway Load Comparison
Nain et al., International Journal of Advanced Research in Computer Science and Software Engineering 4(8),
August - 2014, pp. 648-658
© 2014, IJARCSSE All Rights Reserved Page | 655
Figure 10: Comparison of protocols for lower Mobile hosts speed
Figure 11: Comparison of protocols for faster mobile host speeds
Here the graph indicates that the throughput for MTIMIP is maximum even in case of very high mobility so this
provides the smooth communication for highly moving users.
C. Varying Packet Size Here the throughput has been shown for the packet size 500 and 1000 bytes in both the cases the MTIMIP returns the
highest values as compared to the other macro/mobility providers. MIP gives higher throughput for higher packet size than
MTIMIP . Here the graph also shows that the throughput is maximum for the MTIMIP for a longer period of time and thus
this protocol can be used for real time traffic communication with varying packet sizes as video communication.
Figure 12: Comparison of Protocols for packet sizes 500
Nain et al., International Journal of Advanced Research in Computer Science and Software Engineering 4(8),
August - 2014, pp. 648-658
© 2014, IJARCSSE All Rights Reserved Page | 656
Figure 13: Comparison of protocols for varying packet sizes.1000
Increasing the packet size gives the performance measures decreased as the link capacity as for the default packet rate
100 packets/sec,the load increases the total capacity 1MB/Sec given with simulation environment
Packet Losses: packet losses are minimized to negligible values as graph proclaims.
Nain et al., International Journal of Advanced Research in Computer Science and Software Engineering 4(8),
August - 2014, pp. 648-658
© 2014, IJARCSSE All Rights Reserved Page | 657
D. Comparison for BE traffic
Figure 15: jitter for Best effort traffic
Best effort traffic is used for the Voice over IP communication. The graph shows the jitter for various protocols for BE
traffic which shows the MTIMIP provides the smooth and lesser delay variation so it is most suited protocol for VOIP
communication
V. CONCLUSIONS
This paper presented the evaluation of Modified terminal independent mobility architecture with the presence of link-
failures. This global solution supports legacy terminals with high efficiency, regarding both handover latency and network
resources utilization. Simulations that compared MTIMIP with the other micromobility protocols were performed. In
particular, random link-failures impact is investigated, for both stationary and continuous movement scenarios. In these
simulations, the average results from continuous measurements were presented; featuring varying MN speeds, multiple
metrics (loss ratio, throughput and delay), intra and inter-domain UDP traffic sourcal routing support for all network
locations. HAWAII would also be able to share such good performance with intra-domain traffic, but suffers from long
routing paths due to its incremental handover operations CIP and HMIP have the worst behaviour, as all packets are forced
to pass through the GW.
The continuous movement results showed that all protocols except HMIP have good localized handover support,
minimizing the handover latency in most handovers. By sending the update message directly to the previous AP, MTIMIP
would have the lowest handover latency of all protocols like HAWAII, however, such benefit is cancelled in HAWAII by
the introduction of out of- order UDP packets in each handover, a problem particularly evident in tree topologies. In case of
inter domain traffic HMIP has the worst results, as all handovers require an update to the GW. The results show that for low
speed movement utilizations, the micro-mobility protocols only feature small performance differences between themselves;
however, in high speed movement scenarios, such differences are greatly amplified and can distinguish the protocols.
Of the efficient protocols, MTIMIP has better robustness than the other protocols, a combined result of requiring fewer
hops and of being vulnerable in the downlink paths only.
Future work comprises further MTIMIP improvements in order to support IPv6 support, security, Wimax extension
compatibility.
Above table & graphs shows the various mobility metrics as control load (Average number of forwarded control
packets per MN handover), UDP Service metrics (Drop Ratio, Out of Order ratio, Total losses Ratio, Handover Latency,
UDP throughput ratio), TCP service metrics are being optimized. Thus providing the mobility or transparency (control load,
Gateway load lesser) and efficiency (handover latency optimized) for the proposed protocol. The protocol have also been
found to be best suited for the real time traffic, best effort traffic communication which are used for video data traffic And
voice data traffic respectively so this protocol is highly recommended for multimedia applications in wireless networks.
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