copyright © 2005 juniper networks, inc. 1 schedulable deterministic end-to-end pipes some thought...

Copyright © 2005 Juniper Networks, Inc. www.juniper.net 1

Schedulable deterministic end-to-end pipes

Some thought on Control plane …

Jean-Marc Uze, [email protected]’06 workshop on “Service Oriented

Optical Networks”, Catania, May 13, 2006

mailto:[email protected]

2Copyright © 2005 Juniper Networks, Inc. www.juniper.net

Discussions on “control plane”

signaling

lambda

GMPLS(s)

GRID

middleware

AAA VPNs

Multiple control plane layers Multiple fields(expertise)

Philosophical(Politics)

services


Agenda Mid 90s - Common control plane motivations Towards a common control plane – early attempts 1995-96 - From early attempts to Tag Switching to

MPLS late 1990s: From MPLS to GMPLS Multiple control plane layers Conclusion


Mid 90s: Common control plane motivations

The problem: price/performance of routers

Solution: use ATM switches instead of routers

Control Plane initial choice:• The overlay Model

• ATM Core as an IP subnetwork

• Full mesh of PVCs among router

• Two separate (very different) control planes


Overlay - Lessons learned What’s wrong with the overlay model ?

• How to handle (redundant) functionality?

• How to support routing peering hierarchy (needed for scalability) among the routers connected to an ATM network ?

• ATMARP, MARS, NHRP, LEC, LES, LECS, BUS, etc… trying to bring the two together. Either fairly complex, or broken, or both…

Use of the overlay model requires careful considerations of interactions between control planes• Enabling the same functionality at multiple layers of network may

produce quite a few surprises

• What is the proper layer of network for a particular functionality ?

Large scale overlay does not fit well with the IP control plane (due to the large number of IP routing adjacencies)


Towards a common control plane – early attempts Problem: Can both routers and ATM switches be controlled by a

common control plane ? - Yes

Solution: Extend IP control plane to control ATM switches - common control plane that spans both routers and ATM switches

• CSR by Toshiba and IP switching by Ipsilon

• Key Features:

• IP based control plane, Forwarding state (VCI/VPI) at the granularity of individual TCP flows or host source/destination pairs

• Short-lived flows forwarded using control plane resources, Long-lived flows forwarded using data plane resources (ATM data plane)

• Control plane creates/maintains forwarding state (ATM VCI/VPI) in response to data plane traffic

BUT

• Unscalability of forwarding granularity to TCP flows or host source/destination for large scale Internet.

• Data-driven establishment of forwarding state creates interference with the control plane


new

sam

e a

s befo

reFrom early attempts to Tag Switching to MPLS - MPLS main ideas

Separate forwarding information (label) from the content of IP header

IP based control plane (OSPF, ISIS, BGP, RSVP, etc…) Multiple link-specific realizations of the label swapping

forwarding paradigm• Label swapping is for routers too (not just for ATM switches)

Forwarding Equivalence Classes (FECs):• Groups of packets forwarded over the same Label Switched Path

(LSP) • As a packet enters an MPLS network, it is assigned a label based

on its Forwarding Equivalence Class (FEC)• as determined at the edge of the MPLS network

• Wide range of forwarding granularities due to the flexibility of forming Forwarding Equivalence Classes (FECs)

Forwarding hierarchy via label stacking Control traffic driven creation of forwarding state


From MPLS to GMPLS Justification for ATM switches to interconnect routers

faded away But OXCs and TDM cross-connects arrived, and

without a standard-based control plane “G” in GMPLS stands for “generalized”

• Many commonalities with MPLS

• What is generalized: label, constraints, separation of control and data plane (out-of-band control plane)

GMPLS is not a superset of MPLS GMPLS is a proper superset of

MPLS Constraint based routing(MPLS TE)


GMPLS – what is new for packet-based LSPs ? Bidirectional LSPs Unnumbered links Link bundling LSP hierarchy (forwarding adjacencies)

• Improves control and data plane scalability

• Regions based on “colors”, routing areas, ASs

Multi-region LSP (multi-area, multi-AS)

GMPLS – technology push vs market pull• High demand of bandwidth: Dot-com bubble burst revealed the

mismatch between the assumptions about bandwidth demand and the reality

• Recently started to gain more market attention, due to the continuous growth of bandwidth demand. Was a bit ahead of its time at the time of creation – its time seems to have come now


GMPLS – lessons learned

Generalization is a very powerful concept !!! Try to build solutions to new problems by

generalizing the existing solutions, rather than develop new solutions•By focusing on what is common

•By generalizing the existing concepts/models/mechanisms

If new solutions have to be developed, try to avoid point solutions – design new solutions with the generalization in mind


Potential implementation with IETF inter-domain GMPLS TE

NREN 1

NREN 1

NREN 2

NREN 2

NREN 3

NREN 3

R1R2

A12

A21

A22

A23

A24

A31

A32

Inter-AS TE-LSP R1-R2 : bw = 100m, CT = IP PremiumASBR-Path: A21-A31-R2

Path Path Path PathBw= 100CT = IP Premium

PathA11

ResvResv

ResvResvResv

Policing Policing

GMPLS TE is originally intra-domain (RSVP-TE with routing IGP TE extensions) Inter-domain GMPLS TE extends signaling and routing protocols to set-up an LSP

across multiple providers Need for proper policing and filtering of RSVP-TE messages at NREN boundaries

• Filter/modify QoS parameters Need for scheduling In this example the Path Computation is performed per domain (route expansion)

• Need for Provider-chain selection based on NRENs business relationship

R1-A21Path comp

A 21-A31Path comp

A 31-R2Path compWhat is missing ?


Towards a new layer to handle business relationships

TransportNetwork

NetworkManagement

Potentially a Higher Layer Middleware (e.g. GRID)

TransportNetwork

NetworkManagement

BusinessLayer

BusinessLayer

3 3

4 4

1 12

QoS?

Reliability?

Security?


Conclusion R&E community implements what prefigures future Internet

networks• Opportunity: contribute to standardization bodies on this new business

or service layer (e.g. IPsphere Forum). Please join the TNC session 6c on Wednesday, on “Networks on Networks - Grids”)

• Do not build technology that will be used just by a private “club” (there could be several clubs)

• Try to solve all on-demand services issue, not only optical services

Carriers are not completely different from R&E networks• Key difference: profitability

• Key commonalities:

• Need for dynamic end-to-end services across multiples network, triggered by application

• Need of COTS equipment and standards. The difference is how this technology is implemented (use cases, fast, scale, operations etc.)

Thanks !!!

And thanks Yakov Rekhterfor his testimony, thoughts and vision on

MPLS

copyright © 2005 juniper networks, inc. 1 schedulable deterministic end-to-end pipes some thought...

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