M MP PL LS S ( (M Mu ul lt ti i P Pr ro ot to oc co ol l L La ab be el l S Sw wi it tc ch hi in ng g) )

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MPLS Overview

(What is MPLS?)


Over the last few years
, the Internet has developed very quickly. So, it can drive a variety of
new applications to evolve too. These new applications
also know as real time applicati
on,
including
new voice, picture and multimedia services are being developed and deployed into present
-
day
network technologies. That i
s the reason why we should

to develop telecommunication and network
services
for support many new application which estab
lish in this time. Therefore, the new core
network technology such as MPLS is an interested solution that it will play an important role in the
routing, switching and forwarding of packets through the next
-
generation network in order to meet
the service de
mands of the network users.


MPLS or Multiprotocol label switching

is a new network protocol that defined a mechanism
for packet forwarding in network router. It was originally developed to provide faster packet
forwarding than traditional IP routing by IE
TF

(Internet Engineering Task Force)
, a large open
international standard organization with no formal member

for develops and promotes Internet
standards, although improvements in router hardware have reduced their importance of speed in
packet forwarding
However, the flexibility of MPLS has led to it becoming the default way for
modern network to achieve Quality of Service (QoS), next
-
generation VPN, and optical signaling.


Traditional IP networks send and receive data by router using IP packet. All IP pac
kets have

a
header which contained
the address of source and
des
tination
and also keep their data on it.
However, this traditional IP working format, it has a waste of time
caused

finding the next hop till
steps and

the way to send the information to desti
nation. MLPS also uses IP addresses with an
identifier (label) to identify end point and intermediate switches and routers
,

it can help packet
forwarding send and receive the data faster than tradition IP routing
. This makes MPLS networks IP
compatible and

easily integrated with traditional IP network.


MPLS Architecture




The MPLS architecture is divided into two components. The first is called the control
component (the control plane). It created and maintained la
bel
-
forwa
rding information surrounded
by

a group of interconnected label switches

which IP routing protocols can exchange routing
information and another component manages label distribution. It also maintains label information
base (LIB) and create a label forward
ing information base (LFIB). T
he second is called the forwarding
component (the data plane).

It uses a label
-
forwarding database maintained by a label switch to
perform the forwarding of data packets based on labels carried by packets which packet ask the

LFIB
for proper forwarding in an outgoing direction.

How do MPLS work?

MPLS operates at an OSI model layer between Layer 2 (Data Link Layer) and Layer 3
(Network Layer), so it is often referred as a Layer 2.5 protocol. It combines the benefits of packet
f
orwarding based on Layer 2 switching with the benefits of Layer 3 routing.

IP Routing Protocol

Routing Table

Label Generation &
Management

Label
Information
Base (LIB)

Label Forwarding
Information Base
(LIFB)

Packet Forwarding

Routing

Information
Exchange

Control
Compo
nent

Forwarding
Component

Outgoing
MPLS Packet

Incoming
MPLS Packet


The main function of MPLS is organizing the path of packet or new routing in the particular
path which referred to as a LSP (Label Switch Path). When a packet is received, MPLS ad
ds a Label in
front of a packet as another header, so that routers know how to act based on this label. Routers
must be label
-
switched routers (LSRs) and each LSR must maintain a valid mapping from the label of
an incoming packet (incoming label) to a labe
l to be attached to the packet before being sent out
(out
put label). The router uses the

label to identify the LSP. Then, it looks up the LSP

in its own
forwarding table to determine the best path over which to forward the packet and the lab
el to use
on th
is next hop.
A different label is used for each hop, and it is chosen by the router or switch
performing the forwarding operation. This allows the use of very fast and simple forwarding engines,
as the router can select the label to minimize processing
.
An

LSP must already be established
between two routers so that packet can follow this path. To establish a path, a label distribution
protocol is used. How do we know this is the best path for the particular class of traffic flows? This
will depend on the tr
affic engineering requirements of the network and on the service requirements
of the traffic flow to be traffic flow to be carried by the LSP.

As MPLS uses only the label to forward packets, it is protocol
-
independent, hence the term
"Multi
-
Protocol" in MP
LS. Packet forwarding has been defined for all types of layer
-
2 link
technologies, with a different label encoding used in each case
.


Advantages and Disadvantages

MPLS is a mechanism in high
-
performance telecommunications networks, which directs and
carri
es data from one network node to the next. MPLS makes it easy to create "virtual links"
between distant nodes. It can encapsulate packets of various network protocols. A number of
different technologies were previously deployed with essentially identical g
oals, such as frame relay
and ATM. MPLS technologies have evolved with the strengths and weaknesses of ATM in mind.
Many network engineers agree that ATM should be replaced with a protocol that requires less
overhead, while providing connection
-
oriented se
rvices for variable
-
length frames. MPLS is currently
replacing some of these technologies in the marketplace. It is highly possible that MPLS will
completely replace these technologies in the future, thus aligning these technologies with current
and future

technology needs. There are five main advantages of MPLS: QOS Capabilities,
performance upgrade, disaster recovery, future
-
proofing the network and cost
-
effective.
It also have bandwidth up to 10 Gbps for business customers, can choose
the speed of it
between 64 Kbps to 1 Gbps. And there are one main weakness is routing intelligence.





The first main advantage of using MPLS services is its QoS capabilities. This is of upmost
importance for companies utilizing voice

and video. Second, performance upgrade, increased
response time and improved application performance is advantages for utilizing MPLS services. This
reduces the number of "hops" between network points, which are the "any
-
to
-
any" features MPLS
offers. The
third advantage is disaster recovery. These services offer data backup/disaster recovery
capabilities by connecting data centers and other key sites in multiple redundant ways to the cloud.
Unlike Frame Relay and ATM networks, which require either switched

or backup permanent
-
virtual
-
circuits, MPLS services allow remote sites to quickly and easily reconnect to backup locations, when
applicable. This flexibility is a major advantage of MPLS over Frame Relay and ATM. Fourth, future
-
proofing the network. Busin
esses realize MPLS is "the wave of the future" and are making the switch
from Frame Relay and ATM services to MPLS. This switch is mainly for fear that they will be left
behind. Competition is tight among businesses in all industries, so having a more cost
-
effective and
more efficient network system gives them a fighting chance. The last advantage of MPLS services is
cost
-
effective. MPLS services are cheaper than Frame Relay and ATM data services between 10% to
25%. If voice and data capabilities are added,

the savings can jump up to approximately 40% for the
entire network.

The one main MPLS’ weakness resides in its inability to provide application
-
level routing
intelligence, a fundamental component for voice delivery.


For example, MPLS is not able to pro
vide
alternate routing on the call level to prevent latency, delay, packet loss and jitter for VoIP packets.
To provide the uncongested (low latency, jitter and packet drop) label switched path (LSP) crucial for
VoIP traffic, the MPLS network must be able
to recognize the VoIP packets and distinguish them
from data packets on the network.

This level of intelligence is not found in MPLS. Just as important,
most VoIP traffic today is long
-
distance, and much of it is international long
-
distance, meaning these
calls typically traverse multiple networks (domains). As discussed at the beginning of this article,
MPLS deployments are domain
-
specific and are therefore not a feasible solution for voice traffic
traversing multiple domains.

MPLS is invented for reducing

the procedure of sending data by IP packet. There are many
advantages of using it, such as, QOS Capabilities, performance upgrade, disaster recovery, future
-
proofing the network, cost
-
effective, etc. It makes packet loss less and also faster than previous

protocols.


Service provider

MPLS (IP VPN) is a data communication
service, which work in a full me
sh network, provide
a high reliability and make employee and organization more convenience via LAN, or intranet
including E
-
Commerce applications.

MPLS allo
w sending package via IP Protocol on ATM network , which has an ability to handle
huge amount of service with a lower cost, and provide a ready to use service that allow user to
access their network anywhere they want via an LAN, Intranet or Dial connectio
n

MPLS
-
network consists of routers and switches connected to transport facilities such as fiber
optic links. Customer connects to core network via multiservice edge (MSE) router. The core network
comprises the core routers that provide high
-
speed connectio
n. An MSE router contains different of
line cards and physical interface to provide layer 2 and layer 3 services.

For the incoming data, external interface will sent data to line card, and then line card will
forward them to the switching fabric. For the o
ut
-
going data, line card receives packets from
switching fabric and forward them to outgoing interface. All operation will pass through the
switching fabric, which is the heart of the router, and used for switch packets between line cards.

There are 3 popu
lar MPLS service provider in Thailand that is CAT, True and 3BB

CAT provide 2 type of service that are ACASIA Direct IP


ACASIA Direct IP


-

LAN and Intranet connection via IP protocol


-

Connect L
AN and Intranet among organizations


-

Port speed up to 2 Mbps


ACASIA Dial IP


-

Connect stand alone computer to LAN and intranet by using Dial up connection


-

Connect compute
r to LAN or Intranet via PSTN network with the maximum speed

o

o
f 56K


-

Username and password are required for connection

True provide 2 types of MPLS service, that are MPLS VLL which is a point to point conne
ct, and
MPLS VPN which is point to multipoint. Both type of the service provide reliable and secured
service and support CoS (Customer of service) and QoS (Quality of service) like Leased line and
Frame Relay.

3BB (3 broad band) provide IPMPLS

Leased line

for organization that want to connect branch
via core network by MPLS technology. This service support QoS (Quality of service) that have
high efficiency to transfer information, picture video and application that applies in organization.

All of these se
rvice providers have the same point to service like offer simple design network
solution, have core network that can support large bandwidth, easily to scale if have new sites is
add to the network, employee can access to all site with single administratio
n, as secure as
Leased Line, Frame relay and ATM. But all of these service providers have a little different in cost,
speed and promotion to service customer.

The future of MPLS


From the details of 4 previous topics, it show you about how MPLS work effici
ency and it has
many advantages for present
-
day network technologies that the reason for why we should to
develop MPLS technology more than this and
the most important MPLS evolution will be MPLS
Transport Profile (MPLS
-
TP) in the future, basically the sam
e as MPLS but with key new features such
as Quality of Service, fast reroute and put that into optical and transport networks that have
typically been based on TDM only, it also improve the level of control from basic MPLS. In addition,
the next key evolut
ion of MPLS is
an ideal technology to use for
4G wireless Long Term Evolution

(LTE), focusing on IP over Ethernet as its standard backhaul technology, MPLS can be successfully
implemented on and LTE network that it will be a major asset to LTE service qual
ity, particularly
when it comes to giving priority to voice and video packets.

แบบย่อๆ

Multiprotocol Label Switching (MPLS) is a standards
-
approved technology for speeding up
network traffic flow and making it easier to manage. MPLS involves setting up a specific
path for a given sequence of packets, identified by a label put in each

packet
, thus saving
the time needed for a

router

to look up the addre
ss to the next

node

to forward the packet
to.
MPLS is called

multiprotocol

because it works with the InternetProtocol

(
IP
),
Asynchronous Transport Mode (
ATM
), and

frame relay
network

protocol
s.

With reference to
the standard model for a network (the Open Systems Interconnection, or

OSI

model), MPLS
allows most packets to be forwarded at the

layer 2

(swit
ching) level rather than at the

layer
3
(
routing
) level. I
n addition to moving traffic faster overall, MPLS makes it easy to manage a
network for quality of service (
QoS
). For these reasons, the technique is
expected to be
readily adopted as networks begin to carry more and different mixtures of traffic.


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