MPLS cisco QOS VPN full MPLS intro

Introduction
MPLS – Technology &
Services
Azhar Sayeed


AS Broadband 99

© 1999, Cisco Systems, Inc.

1


Agenda
• Background and business case
• Technology basics
–

What is MPLS? Where is it used?

• Label Distribution in MPLS Networks
–

LDP, RSVP, BGP

• Building MPLS based Services
–

IP+ATM Integration

–

VPNs

–

Traffic Engineering (FRR & Protection)

• Conclusions

© 1999, Cisco Systems, Inc.

2


Evolution of MPLS
• From Tag Switching
• Proposed in IETF – Later combined with other
proposals from IBM (ARIS), Toshiba (CSR)
Cisco Calls a
BOF at IETF to
Standardize
Tag Switching

Time

1996

MPLS Croup
Formally Chartered
by IETF

Cisco Ships Traffic Engineering
MPLS TE
Deployed

Cisco Ships
MPLS (Tag
Switching)

1997

1998

MPLS VPN
Deployed

1999

© 1999, Cisco Systems, Inc.

Large Scale
Deployment

2000

2001
3


MPLS-Key Drivers

Presentation_ID
AS Broadband 99

© 1999, Cisco Systems, Inc.

© 1999, Cisco Systems, Inc.

4


MPLS as a Foundation for
Value Added Services

Provider
Traffic
Provisioned
Engineering
VPNs

IP+ATM

IP+Optical
GMPLS

Any
Transport
Over MPLS

MPLS

Network Infrastructure

© 1999, Cisco Systems, Inc.

5


US VPN Spending
2000
1800
1600
1400
1200
1000
800
600
400
200
0
1997

1998

1999

2000

2001

2002

Yankee Group Predictions for VPN Spending ($US

Infonetics VPN Spend Projections in ($US millions

millions)

© 1999, Cisco Systems, Inc.

6


New Applications for VPN
VPN Types Implemented by 2002
80%
60%

73%

64%

40%
20%
0%

27%
I ndividual Site-to-site
Remote
Access

Extranets

Source: Infonetics April 2000
© 1999, Cisco Systems, Inc.

7


The Service Provider
Challenge
• Generate New services
• Protect Existing Infrastructure –
ATM/FR
• Combine Private Data Services with
Internet Services
• Move into rapid deployment
© 1999, Cisco Systems, Inc.

8


Technology Specifics

AS Broadband 99

© 1999, Cisco Systems, Inc.

9

Encapsulations
ATM Cell Header

GFC

VPI

VCI

PTI

CLP HEC

DATA

Label

PPP Header
(Packet over SONET/SDH)

PPP Header

Label Header

Layer 3 Header

LAN MAC Label Header

MAC Header

Label Header

Layer 3 Header

© 1999, Cisco Systems, Inc.

10


MPLS Operation – Re-Cap
1a. Existing routing protocols (e.g. OSPF, IS-IS)
establish reachability to destination networks
1b. Label Distribution Protocol (LDP)
establishes label to destination
network mappings.

2. Ingress Edge LSR receives
packet, performs Layer 3 valueadded services, and “labels”
packets

4. Edge LSR at
egress removes
label and delivers
packet

3. LSR switches
packets using label
swapping
© 1999, Cisco Systems, Inc.

11


Label Distribution in
MPLS Networks

AS Broadband 99

© 1999, Cisco Systems, Inc.

12


Label Distribution Protocol
• Defined in RFC 3035 and 3036
• Used to distribute Labels in a MPLS network
• Forwarding Equivalence Class
»

How packets are mapped to LSPs (Label Switched Paths)

• Advertise Labels per FEC
»

Reach destination a.b.c.d with label x

• Neighbor discovery
»

Basic and Extended Discovery

© 1999, Cisco Systems, Inc.

13


Label Distribution Protocol

• Label Merge
»

Done by default for packet networks –
unique label advertised per FEC

»

Requires VC merge for ATM networks

© 1999, Cisco Systems, Inc.

14


TDP & LDP

• Tag Distribution Protocol
»

Pre-cursor to LDP

»

Used for Cisco Tag Switching

• TDP and LDP supported on the same box
»

Per neighbor/link basis

»

Per target basis

© 1999, Cisco Systems, Inc.

15


RSVP & Label Distribution
• Used in MPLS Traffic Engineering
• Additions to RSVP signaling protocol
• Leverage the admission control mechanism of RSVP
• Label requests are sent in PATH messages and binding is
done with RESV messages
• EXPLICT-ROUTE object defines the path over which setup
messages should be routed
• Using RSVP has several advantages
»

Traffic Engineering, Shared Explicit, FRR

© 1999, Cisco Systems, Inc.

16


MPLS Example:
Forwarding Packets
In
label

Address
Prefix

Out Out
I’face label

In
label

Address
Prefix

-

128.89

1

-

171.69

...

...

Out Out
I’face label

4

4

128.89

0

9

1

5

5

171.69

1

7

...

...

...

...

...

...

In
label

Address
Prefix

Out Out
I’face label

9

128.89

0

-

...

...

...

...

0

128.89

0
128.89.25.4
1
128.89.25.4

Data

4

9
128.89.25.4

Data

Data

1

Label Switch forwards
based on label
© 1999, Cisco Systems, Inc.

128.89.25.4

Data

171.69

17


Label Stacking
• IGP Labels – Used for routing packets
• BGP Labels – Used for assigning end
users/communities
• RSVP Labels – Used for TE tunnels
• If more than one service is used
–

Then multiple labels are required – TE and FRR

–

In some cases a single service requires the use of
multiple labels - VPNs

© 1999, Cisco Systems, Inc.

18


Label Stacking – how?
• Arrange Labels in a stack
• Inner labels can be used to designate services/FECs etc
»

E.g VPNs, Fast Re-route

• Outer label used to route/switch the MPLS packets in the
network
• Allows building services such as

Outer Label

»

MPLS VPNs – Basic & Advanced - CSC

»

Traffic Engineering and Fast Re-route

TE Label

»

VPNs over Traffic Engineered core

IGP Label

»

Any Transport over MPLS

VPN Label
Inner Label

© 1999, Cisco Systems, Inc.

IP Header
19


MPLS based services

AS Broadband 99

© 1999, Cisco Systems, Inc.

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Provider Provisioned
VPNs

AS Broadband 99

© 1999, Cisco Systems, Inc.

21


Categories
• BGP MPLS VPNs – RFC 2547
–

Supported by Cisco

• Virtual Routers –
–

Alternative proposal – relies on logical
partitioning of the physical box

–

Requires the use of Multicast/broadcast for
better convergence

© 1999, Cisco Systems, Inc.

22


MPLS Based IP-VPN
Architecture

• Scalable VPNs
• IP QoS and traffic
engineering
• Easy to manage and No VPN A
VC provisioning required Site 2
• Provides a level of
Security equivalent to Corp A
Frame-relay and ATM
Site 1
• Supports the
deployment of new
value-added
applications
• Customer IP address
freedom

Corp B
Site 3

VPN MembershipBased on Logical
Port
VPN A
Site 3
MPLS
Network
MPLS VPN Renault

Corp B
Site 2

MPLS VPN Bankcorp
Corp B
Site 1
Traffic Separation at Layer 3
Each VPN has Unique RD

© 1999, Cisco Systems, Inc.

23


Using Labels to Build an IP
VPN
Cust A

A

A

---------

Cust A

---------

B
---------

B
---------

Cust A

MPLS
Network

Cust B

Cust B

• The network distributes labels to each VPN
- only labels for other VPN members are distributed
- each VPN is provisioned automatically by IP routing
• Privacy and QoS of ATM without tunnels or encryption
• each network is as secure as a Frame Relay connection
• One mechanism (labels) for QoS and VPNs - no tradeoffs
© 1999, Cisco Systems, Inc.

24


Service Provider Benefits
of MPLS-based VPNs
VPN BVPN A
VPN C
VPN C

Multicast
VPN B

Hosting
Intranet

VPN A

VoIP
VPN A

Extranet

VPN B
VPN C

VPN A VPN B

VPN C

• MPLS-based VPNs

• Overlay VPN
– pushes

content outside the
network
– costs scale exponentially
– transport dependent
– groups endpoints, not groups
– complex overlay with QoS,
tunnels, IP
© 1999, Cisco Systems, Inc.

– enables

content hosting
inside the network
– “flat” cost curve
– transport independent
– easy grouping of users and
services
– enables QoS inside the VPNs
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