Transcript Session AII.1 - AGH University of Science and Technology

Scalability of IP/MPLS networks
Benchmarking Carrier Ethernet Technologies Workshop
Session AII.1: PW/MPLS
Krakow, Poland
Lieven Levrau
30th
April, 2008
France Telecom,
Cisco Systems,
uawei Technologies,
Telekomunikacja Polska S.A.
ECI Telecom,
Alcatel-Lucent
All Rights Reserved © Alcatel-Lucent 2006, #####
dsl20081 111 02.ppt
Agenda
1. MPLS control plane: Scaling the IGP to each scenario
2. MPLS transport tunnels: Scaling MPLS to each scenario
2 | Session AII.1 | April 2008
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Use cases
Services to be offered by the IP/MPLS network:
 L2VPN P2P (VPWS)
 for mobile backhauling, non-routable residential traffic
 L2VPN P2MP or MP2MP (VPLS)
 for enterprise customers
 L3VPN (IPVPN)
 for routable residential traffic
3 orders of magnitude for deployment scenarios:
 Scenario 1: 1k PE nodes
 Scenario 2: 10k PE nodes
 Scenario 3: 100k PE nodes
3 | Session AII.1 | April 2008
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1
4 | Session AII.1 | April 2008
MPLS control plane:
Scaling the IGP to each scenario
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IGP scalability with 1k nodes
IP/MPLS
L2 ISIS area
PE
ISIS or OSPF
P
P
ISIS or OSPF
PE
ISIS or OSPF
Routing
L2 ISIS
A single area is sufficient for the IGP
 ISIS or OSPF are eligible
5 | Session AII.1 | April 2008
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IGP scalability with 10k nodes
IP/MPLS
ABR
L1 ISIS area
IP/MPLS
IP/MPLS
L1 ISIS area
L2 ISIS area
ABR
IP/MPLS
ABR
P
PE
ISIS
P
ISIS
P
ISIS
L1 ISIS area
P
ISIS
P
PE
ISIS
ISIS
Routing
L1 ISIS
L2 ISIS
L1 ISIS
Multiple areas are required for the IGP
 ISIS or OSPF are eligible
Area Border Routers are required to control redistribution between areas
 Routes are aggregated
 Only Loopback addresses from one area are redistributed into other areas
6 | Session AII.1 | April 2008
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IGP scalability with 100k nodes
IP/MPLS
ABR
L1 ISIS area
IP/MPLS
IP/MPLS
IP/MPLS
L1 ISIS area
L2 ISIS area
ABR
IP/MPLS
ABR
PE
P
PE
IGP
ISIS
P
ISIS
P
ISIS
L1 ISIS area
P
ISIS
P
ISIS
ISIS
Routing
RIP
L1 ISIS
L2 ISIS
IGP discontinuity is required:
 Different instances of a single IGP
 or different IGPs
 or different AS
7 | Session AII.1 | April 2008
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PE
L1 ISIS
2
8 | Session AII.1 | April 2008
MPLS transport tunnels:
Scaling MPLS to each scenario
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Needs for QoS and resiliency drive the choice for the LSP
technology
CAC and sub-100ms resiliency require MPLS traffic engineering:
 TE-LSPs (RSVP-TE signaled LSP) as the technology for MPLS transport
tunnels
Otherwise :
 LDP-LSPs (LDP signaled LSP) as the technology for MPLS transport tunnels
For each network segment, either TE-LSP or LDP-LSP need to be chosen.
9 | Session AII.1 | April 2008
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Scaling up to 1k Provider Edge nodes
IP/MPLS
L2 ISIS area
RR
P
PE
Routing
LSP label allocation
PW label allocation
L3VPN label allocation
and route distribution
ISIS or OSPF
LDP or RSVP-TE
P
PE
ISIS or OSPF
ISIS or OSPF
LDP or RSVP-TE
LDP or RSVP-TE
targeted LDP
MP-BGP
RR
For LDP-LSPs, a flat VPN model is sufficient (RFC 5036)
For TE-LSPs, the use of hierarchical MPLS-TE is required (RFC 4206)
For L3VPN, BGP Route Reflectors are required (RFC 4364)
10 | Session AII.1 | April 2008
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Scaling up to 10k Provider Edge nodes
IP/MPLS
L1 ISIS area
PE
L1 ISIS
IP/MPLS
ABR
IP/MPLS
L2 ISIS area
ABR
RR
P
L2 ISIS
P
10.0.0/24
10.0/16
10.0.0.1/32
L1 ISIS area
L1 ISIS
10.0.0.1/32
PE
Routing (IGP)
LDP
Label for 10.0.0.1/32
LSP label allocation
PW label allocation
targeted LDP
L3VPN label allocation
and route distribution
MP-BGP
RR
Inter-area support is required (within a single MPLS domain) :
 draft-ietf-mpls-ldp-interarea-03.txt
 Allows to setup LSPs across IGP areas without having to distribute in the IGP
each /32 PE loopback => ABRs aggregate routes to reach loopback addresses
11 | Session AII.1 | April 2008
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Redistribution
between IGP areas
Scaling up to 100k Provider Edge nodes
MS-PW
T-PE
S-PE
ABR
Distinct IGP
Or distinct IGP instance
MS-PW
S-PE
T-PE
PW1
Spoke-PW
VPLS
Edge PE
PW3
S-PE
PW2
Hub-PW
VPLS
Core PE
T-LDP
L2 ISIS area
L1 ISIS areas
PW4
L1 ISIS areas
VPLS
Edge PE
T-LDP
ABR
Hub-PW
VPLS
Core PE
Spoke-PWs
T-LDP
T-LDP
ABR
VPLS
Core PE
T-LDP
MPLS service segmentation is required (multiple MPLS domains):
 For VPWS, multi-segment PW are required:
 draft-ietf-pwe3-segmented-pw-07.txt
 For multipoint L2VPN, hierarchical VPLS are required:
 RFC 4762
Such segmentations alleviate issues of number of LSPs in core network
L3VPN not addressed in this presentation
12 | Session AII.1 | April 2008
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Thank you
14 | Session AII.1 | April 2008
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Backup Material
15 | Session AII.1 | April 2008
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Solutions' family for scaling MPLS
Single MPLS domain solution
 Flat VPN architecture: end-to-end PSN tunnels, PEs at the MPLS edges
Multiple MPLS domain solutions
 Network segmentation with the intervention of border routers (ASBRs or
ABRs) in MPLS label exchange and MPLS traffic forwarding
 Still PSN tunnels between ultimate PEs (Flat VPN architecture), but segmented on the
infrastructure level
 Service segmentation with the introduction of intermediate PEs
 PSN tunnels between ultimate PEs and intermediate PEs
Several solutions
 Each solution solves a set of issues
 All these solutions can coexist
16 | Session AII.1 | April 2008
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Overview of IETF solutions' families
Single MPLS domain
Number
of PEs
Segmented routing plan
Flat VPN
(end-to-end LSPs between ultimate PEs)
LDP-LSPs
Mono-AS, Mono-area
1k
Mono-AS, Multi-area
Full mesh of TE-LSPs
possible with
hierarchical TE (RFC
4206) (5) (3)
Not needed
LDP inter-area:
draft-ietf-mpls-ldpinterarea-01.txt
Not feasible due to
the number of LSPs,
if full mesh required
(1) as PSN tunnels
LDP (or RSVP-TE) +
BGP:
to be noted that
LDP-LSPs as PSN
tunnels can be nested
into some set of
smaller TE-LSPs
(3)
Mono-AS, Multi-area
100k
+ multi-instance IGP or ≠
IGPs
Network
segmentation
TE-LSPs
No added feature
required (distribution
of IP/32 addresses into
the IGP)
can be combined
with MP-BGP L2VPN
(RFC4761) for flat
L2VPN, wrt signaling
scalability
10k
Multiple MPLS domains
Not feasible due to the
number of LSPs (1)
RFC 3107 Carrying Label
Information in BGP-4
LDP Aggregate FEC:
draft-swallow-mplsaggregate-fec-00.txt and
draft-swallow-isisdetailed-reach-00.txt
(4)
can be combined
with MP-BGP L2VPN
(RFC4761), wrt
signaling scalability
Not feasible due to
the number of LSPs
Not feasible due to
the number of LSPs
(1)
(1)
Multi-AS
17 | Session AII.1 | April 2008
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Service segmentation
(intermediate PEs)
Not needed as transport
LSPs are concerned
MS-PW with FEC129:
draft-ietf-pwe3-segmented-pw06.txt
HVPLS RFC4762
HVPLS associating
RFC4762 and 4761
PBB-HVPLS draft-balusl2vpn-vpls-802.1ah-01.txt
VRF back-to back (for
L3VPN; option a or d) and
similarly Layer2peering
(for L2VPN)
As above (2) :
MS-PW; HVPLS
VRF back-to back;
Layer2peering