Copyright 2004 Lucent Technologies Inc. All rights reserved. MPLS Network Tuning: How to Squeeze Most From Your Network Swarup Acharya ([email protected]) Technical Manager, Multiservice Networking Research Group Optical Networking Division, Bell Laboratories
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Copyright 2004 Lucent Technologies Inc. All rights reserved. MPLS Network Tuning: How to Squeeze Most From Your Network Swarup Acharya ( [email protected].
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Copyright 2004 Lucent Technologies Inc. All rights reserved.
– For live, operational networks, not greenfield designs
12Copyright 2004 Lucent Technologies Inc. All rights reserved.
Re-cap
Did the Net-Heads check with the Bell-Heads as to what NM quagmire they were getting into?
MPLS Traffic Engineering:
• Helps avoid congestion prevalent in native IP networks
• Limited ability to mitigate circuit-switched inefficiencies
• On its own, cannot extract the most juice from the network
Critical need for Network Tuning tools
No reason why MPLS cannot become equally inefficient down the road..
Key Tradeoff:
Grow infrastructure to meet traffic demand [CapEx Hit], OR,
Tune network for improved efficiency [OpEx Hit]?
13Copyright 2004 Lucent Technologies Inc. All rights reserved.
Network Tuning Scenarios
The router rejected a new LSP setup request due to insufficient bandwidth. Can I engineer the current LSP routes to “free” the necessary bandwidth for the new one?
I need to bring down a router for an OS upgrade. Can I:
a) Re-route the LSPs on the router to avoid bringing them down?
b) Upgrade the router OS and then revert them back to their original routes?
The traffic on a node/set of links had exceed the recommended load threshold. Can I move traffic from the “hot zone” to minimize damage in case of failure?
Can I have automated, scalable Network Tuning tools?
14Copyright 2004 Lucent Technologies Inc. All rights reserved.
Bell Labs Möbius Tool:MPLS Provisioning, Tuning System
Link color indicates load (Red: high, Green: acceptable load)
Support For:- Cisco
72*/75*/120*
- JNPR M*, T* - ERX
15Copyright 2004 Lucent Technologies Inc. All rights reserved.
Möbius LSP View
16Copyright 2004 Lucent Technologies Inc. All rights reserved.
Network Tuning: Fail-Setup Optimization
17Copyright 2004 Lucent Technologies Inc. All rights reserved.
Network Tuning: Fail-Setup Optimization
18Copyright 2004 Lucent Technologies Inc. All rights reserved.
Network Tuning: Fail-Setup Optimization
19Copyright 2004 Lucent Technologies Inc. All rights reserved.
Optimization Done!
Network Tuning: Fail-Setup Optimization
20Copyright 2004 Lucent Technologies Inc. All rights reserved.
Impacted Circuits (Old Routes)
21Copyright 2004 Lucent Technologies Inc. All rights reserved.
Impacted Circuits (Old + New Routes)
1: Re-route
2: Re-route 3: Provision
22Copyright 2004 Lucent Technologies Inc. All rights reserved.
23Copyright 2004 Lucent Technologies Inc. All rights reserved.
Network Engineering Requirements
Step-by-step Migration Sequence– Operating on live traffic -- providing a design for an “optimized” layout
does not help
How do I get from current LSP layout to the new layout?
– Original LSP QoS constraints have to be maintained on new route
C
DBF
E A
L2L1
L3
C
DBF
E A
L2
L1
L3
C
DBF
E A
L2
L1
L3L4
Re-route L2 Re-route L3 Provision L4
24Copyright 2004 Lucent Technologies Inc. All rights reserved.
Algorithmic Challenge
Migration a very challenging theoretical problem (“NP-hard”)
– Problem of scale -- exponential search space
Requires innovative algorithms for large networks
How to scale to a network with 10s of routers, 100s of links and 1000s of LSPs?
In Bell Labs, we have patent-pending algorithms to provide migration sequence in “real-time”
– Milliseconds to seconds for reasonable sized networks
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30 50 70 80 90
Network Load (%)
% H
ot
Zo
ne
Cle
ared
HZ LSP Rerouted Non HZ LSP Rerouted
Hot Zone Load Balancing
• Hot Zone size = 10% Network• Goal: Clear all LSPs in Hot Zone• Chart shows contribution of LSPs outside the hot zone in meeting the goal as network loads increase
25Copyright 2004 Lucent Technologies Inc. All rights reserved.