Post on 11-Jan-2016
description
MPLS TE Over ATM
Advisor: Dr. Ravi Pendse
Presented by: Deepak Gulla Nishant Tambe
Outline
Goals MPLS basics with Traffic Engineering ATM basics with ATM Traffic Management Network Scenario Results / Observations Conclusions Future Work
Goals
Effects of link loading and link failure on an ATM network running MPLS Traffic Engineering (TE)
Behavior of Non-Real Time Traffic
Behavior of Real Time Traffic
MPLS with TE
MPLS with TE
IP domain IP
domain
ISP Backbone
ATM backbone ATM with
TM
MPLS Tunnel
Overview Model
Basic Network Scenario
ATM LSR
Edge LSR
LC-ATM Interfaces
hosts
hosts
LSR: Label Switch Router
LC-ATM: Label Controlled ATM
Links used : OC-3 ( 155.4 Mbps)
R5
ATM 1
R4
ATM 3
R7
ATM 2
R8
What is MPLS?
It’s a high performance method for forwarding packets through a network.
It’s a multi protocol because it can work with protocols like OSPF,RSVP,LDP, BGP etc.
It uses label (a short fixed length) with packet. All packets with same label use the same path -
a so-called label switched path (LSP). Because labels refer to paths and not endpoints, packets destined for the same endpoint can use a variety of LSP’s to get there.
Why MPLS?
Fast forwarding Traffic Engineering Virtual Private Networks It combines the scalability and flexibility
of routing with performance of layer 2.
MPLS Label Format
Layer 2 Header Layer 3 HeaderMPLS Shim Header Packet dataHeader
Label20 bits
EXP3 bits
S1bit
TTL8 bits
32 bits
Label Distribution Protocol
Request 56.2 Request 56.2
Mapping 0.40 Mapping 0.30
56.1
2 1 11 22
Intf In
Dest Intf out
Label out
2 56.2 1 0.40
Intf In
Label in
Dest Intf out
2 0.30 56.2 1
Intf In
Label In
Dest Intf out
Label out
2 0.40 56.2 1 0.30
56.3
56.2
Network 130.10.X.X / 24
3 3 3
11
1
2
22
33
MPLS Operation
Label creation and distribution LFIB table at each router Label switching path and table
lookup Forwarding of packet through the
network
MPLS Traffic Engineering
Optimizes the routing of IP traffic. Routes traffic flows across the network
based on resources the flow requires and the resources available.
Employs “Constraint-based routing” Recovers to link or node failures that
change the topology. Routing protocol used must be a link
state protocol.
ATM
ATM is a ITU-T standard for a cell relay wherein information for services is conveyed in small, fixed size cells.
ATM is a cell switching and multiplexing technology that combines the benefits of circuit switching with those of packet switching.
The cell size in ATM is 53 bytes where the payload is of 48 bytes and the 5 bytes constitutes for the header information.
It’s a connection oriented duplex communication network.
Why ATM ?
Integrated Services High speed Scalable Quality of service Well established industry standard Faster more efficient switching
ATM Cell
01234567
Generic Flow Ctrl. Virtual Path IE
Virtual Path IE Virtual Channel IE
Virtual Channel IE
Virtual Channel IE Payload Type IE
Header Error Check
Payload (48 bytes)
5 B
ytes
48 B
yte
s
CLP
Cell Header
VPI/VCI - Used to route cell to destination 24 bit information, routing significance only
CLP - Cell Loss Priority 1: discard first; 0: try not to discard
PT - Payload Type Data or OAM (Operation, Administration,
Maintenance) Congestion indication End of AAL5 packet
GFC - Generic Flow Control (UNI only) local functions
Types of ATM Connections Types of ATM Connections
•PVC (Permanent Virtual Connections)•SVC (Switched Virtual Connections)•Fundamental Connections
•Point-to-point•Point-to-multipoint
ATM CoSATM CoS •Constant Bit Rate (CBR) •Variable Bit Rate- Real time (VBRrt)•Variable Bit Rate- Nonreal time (VBRnrt)•Unspecified Bit Rate (UBR)•Available Bit Rate (ABR)
Connection setup through ATM
Connects to B
Connects to B
Connects to B
Connects to B
OK
OK
OK•Signaling request
•Connection routed – setup path
•Connection accepted /rejected
•Data flow- along same path
•Connection tear down
End system A
End system B
ATM Switching Operation
3525 45
25
Port VPI/VCI Port VPI/VCI 1 25 2 35 2 35 1 25 1 45 3 25 3 25 1 45
2
31
Input Output
•Receives cell across a link on a known VCI or VPI value
•Translation table lookup takes place to determine the
outgoing port and new VPI / VCI value is assigned.
•Retransmits cell on that outgoing link with appropriate
identifiers
Basic Network Scenario
ATM LSR
Edge LSR
LC-ATM Interfaces
hosts
hosts
LSR: Label Switch Router
LC-ATM: Label Controlled ATM
Links used : OC-3 ( 155.4 Mbps)
R5
ATM 1
R4
ATM 3
R7
ATM 2
R8
Phase 1: MPLS TE over ATM ( NRT)
ATM LSR
Edge LSR
LC-ATM InterfacesPagent
on R6
R5
ATM 1
Pagent
on R2
R1
R4
R7
ATM 2
R8
R3
ATM 3
Pagent Path
3.2
3.1
2.2
1.2
1.1
5.1
4.2
4.1
5.2
9.2
9.1
LSR: Label Switch Router
LC-ATM: Label Controlled ATM
Links used : OC-3 ( 155.4 Mbps)
2.1
P a t h 1
P a t h 2
P a g e n t p a t h
Path 1
Path 2
rack7r5#sh mpls forwarding-table Local Outgoing Prefix Bytes tag Outgoing Next Hop tag tag or VC or Tunnel Id switched interface 16 Pop tag 10.10.10.6/32 0 AT2/0.1 point2point 17 Pop tag 100.1.4.0/24 0 AT2/0.1 point2point 18 16 100.1.7.0/24 0 AT2/0.2 point2point 19 17 100.1.6.0/24 0 AT2/0.2 point2point 20 Pop tag 10.10.10.3/32 0 AT2/0.2 point2point 21 Untagged[T] 10.10.10.5/32 0 Tu1 point2point 22 21 10.10.10.7/32 0 AT2/0.2 point2point 23 22 10.10.10.8/32 0 AT2/0.2 point2point 24 23 10.10.10.9/32 0 AT2/0.2 point2point 25 Pop tag 100.1.3.0/24 0 AT2/0.2 point2point 26 Pop tag 100.1.5.0/24 0 AT2/0.2 point2point 27 Pop tag 100.1.9.0/24 0 AT2/0.2 point2point 28 26 10.10.10.10/32 0 AT2/0.2 point2point
Result of Phase 1Result of Phase 1
MPLS forwarding table with TE configured: MPLS forwarding table with TE configured:
rack7r5#trace 10.10.10.5
Type escape sequence to abort.
Tracing the route to 10.10.10.5
1 100.1.2.2 [MPLS: Label 27 Exp 0] 92 msec 204 msec 160 msec
2 100.1.3.2 116 msec 112 msec *
Route taken before change of Tunnels (with Route taken before change of Tunnels (with Label info): Label info):
Ping traffic showing packets drop:Ping traffic showing packets drop:
rack7r5#ping 10.10.10.5
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.10.10.5, timeout is 2 seconds:
...!!
Success rate is 40 percent (2/5), round-trip min/avg/max = 28/28/28 ms
Result of Phase 1:Result of Phase 1:
Result of Phase 1Result of Phase 1 Ping showing 100% success after change of Ping showing 100% success after change of Tunnels: Tunnels:
Route taken after change in Tunnels Route taken after change in Tunnels (with label info): (with label info):
rack7r5#ping 10.10.10.5
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.10.10.5, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 28/34/60 ms
rack7r5#trace 10.10.10.5
Type escape sequence to abort.
Tracing the route to 10.10.10.5
1 100.1.1.2 [MPLS: Label 29 Exp 0] 36 msec 36 msec 36 msec
2 100.1.4.1 20 msec 16 msec *
Phase 2: MPLS TE over ATM ( RT)Phase 2: MPLS TE over ATM ( RT)
Pagent on R6
R5
ATM 1
R4 ATM 2
R8
R3
Path 1
Path 2
ATM 3
Pagent Path
R7
T1 Link
T1 Link
Callgen R1
Callgen R2
Pagent on R2
PSQM Server
3.2
2.2
1.2
1.1
5.1
4.2
4.1
5.2
9.2
9.1
2.1
3.1
R1
GW
GW
Result of Phase 2Result of Phase 2Route taken before starting the call:Route taken before starting the call:
Route taken after change the call:Route taken after change the call:
rack7r5#trace 10.10.10.5
Type escape sequence to abort.
Tracing the route to 10.10.10.5
1 100.1.2.2 [MPLS: Label 16 Exp 0] 152 msec 76 msec 80 msec
2 100.1.3.2 64 msec 248 msec *
rack7r5#trace 10.10.10.5
Type escape sequence to abort.
Tracing the route to 10.10.10.5
1 100.1.1.2 [MPLS: Label 32 Exp 0] 36 msec 36 msec 36 msec
2 100.1.4.1 20 msec 20 msec *
Codecs (Kbps)
PSQM scores w/o MPLS TE
(just OSPF)
PSQM scores with MPLS but
no TE
PSQM scores with MPLS TE and no
ATM TM
PSQM scores with MPLS
TE and ATM TM
G.711 (64) 1.419 1.273 2.435 0.972 G.726 (32) 1.942 1.273 2.420 1.329 G.729 (8) 1.460 1.411 3.925 1.203 G.723(6.3) 1.296 1.486 2.223 1.015
Table.1: Synchronization type: 3-tone
Codecs
PSQM scores w/o MPLS TE
(just OSPF)
PSQM scores with MPLS but
no TE
PSQM scores with MPLS TE and no
ATM TM
PSQM scores with MPLS
TE and ATM TM
G.711 0.669 0.670 3.240 0.627 G.726 0.683 1.104 2.486 0.648 G.729 0.709 1.242 3.541 0.674 G.723 0.742 0.921 2.847 0.691
Table 2: Synchronization type: (DTMF)
Codecs PSQM scores w/o MPLS TE
(just OSPF)
PSQM scores with MPLS but
no TE
PSQM scores with MPLS TE and no
ATM TM
PSQM scores with MPLS
TE and ATM TM
G.711 2.012 2.145 4.129 1.746 G.726 2.421 2.104 5.031 2.124 G.729 2.742 2.546 5.112 1.842 G.723 2.396 2.286 4.912 1.910
Table 3: Synchronization type: no-sync
Results of Phase 2:
• During congestion MPLS automatically switches the path to the other path that is under utilized.
• LS1010 is not working as LSR when configured along with the 3600 series routers with the existing IOS, hence we cannot use SVC’s.
• The success rate of the call increased by increasing the PCR value of the switch.
• Due to the configuration done codecs G.729 and G.723 also yielded better results when compared to other codecs inspite of their lower bit rate
Observations
Goals
Effects of link loading and link failure on an ATM network running MPLS Traffic Engineering (TE)
Behavior of Non-Real Time Traffic
Behavior of Real Time Traffic
Conclusions
• The PSQM scores obtained were better for all scenarios by configuring MPLS TE with ATM TM.• Recovery of links is faster when MPLS TE with ATM TM is used.• G.723 inspite of lower bit rate yielded comparably equivalent scores hence for our scenario we would recommend using it.
Future Work
• MPLS QoS can be implemented on the existing scenario by replacing 3600 series with 7200 series routers.• ATM QoS can be implemented by replacing LS1010’s with that of MGX 8500 series switches. • Implement VPN extending our existing network scenario.• Behavior of real time traffic with more number of calls.
•Measure parameters such as jitter, echo, delay etc.
References
• MPLS Technology and Applications – Bruce David & Yakov Rekhter
• Cisco ATM Solutions – Cisco Press
• www.Cisco.com
• RFC 3031
• www.mplsrc.com
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