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Deploying MPLS TE - Cisco System
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© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 1
Deploying MPLS TE
BRKIPM-2002
Santiago Alvarez
2© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Agenda
Technology Overview
Bandwidth optimization
Traffic Protection
TE for QoS
Inter-Domain Traffic Engineering
General Deployment Considerations
http://www.cisco.com/go/mpls
3© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Technology Overview
4© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
MPLS TE Overview
Introduces explicit routing
Supports constrained-based routing
Supports admission control
Provides protection capabilities
Uses RSVP-TE to establish LSPs
Uses ISIS and OSPF extensions to advertise link attributes
TE LSP
IP/MPLS
5© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
How MPLS TE Works
Link information Distribution*ISIS-TEOSPF-TE
Path Calculation (CSPF)*Path Setup (RSVP-TE)Forwarding Traffic down Tunnel
Auto-routeStaticPBRCBTSForwarding AdjacencyTunnel select
IP/MPLS
Head end
Mid-point Tail end
* Optional
6© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Link Information Distribution
Additional link characteristicsInterface address
Neighbor address
Physical bandwidth
Maximum reservable bandwidth
Unreserved bandwidth (at eight priorities)
TE metric
Administrative group (attribute flags)
IS-IS or OSPF flood link information
TE nodes build a topology database
Not required if using off-line path computation
http://www.cisco.com/go/mpls
IP/MPLS
7© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Path Calculation
TE nodes can perform constraint-based routing
Constraints and topology database as input to path computation
Shortest-path-first algorithm ignores links not meeting constraints
Tunnel can be signaled once a path is found
Not required if using off-line path computation
http://www.cisco.com/go/mpls
IP/MPLS
Find shortest
path to R8 with
8Mbps
Find shortest
path to R8 with
8Mbps
R1
R8
55 33
Link with insufficient bandwidth
Link with sufficient bandwidth
1010
1515
1010
1010
88
1010
8© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
TE LSP Signaling
Tunnel signaled with TE extensions to RSVPSoft state maintained with downstream PATH messagesSoft state maintained with upstream RESV messagesNew RSVP objects
LABEL_REQUEST (PATH)LABEL (RESV)EXPLICIT_ROUTERECORD_ROUTE (PATH/RESV)SESSION_ATTRIBUTE (PATH)
LFIB populated using RSVP labels
http://www.cisco.com/go/mpls
IP/MPLSHead end
Tail endRESVRESV
PATHPATH
9© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Traffic Selection
Multiple traffic selection optionsAuto-route
Static routes
Policy Based Routing
Forward Adjacency
Pseudowire Tunnel Selection
Class Based Tunnel Selection
Tunnel path computation independent of routing decision injecting traffic into tunnel
Traffic enters the tunnel at the head end
http://www.cisco.com/go/mpls
IP/MPLSHead end
Tail end
10© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Configuring MPLS TE and Link Information Distribution Using IS-IS (Cisco IOS)
Enable wide metric format and TE extensions (TE Id, router level)
Enable MPLS TE on this node
Enable MPLS TE on this interfaceAttribute flagsTE metricMaximum reservable bandwidth
mpls traffic-eng tunnels!interface POS0/1/0ip address 172.16.0.0 255.255.255.254ip router isismpls traffic-eng tunnelsmpls traffic-eng attribute-flags 0xFmpls traffic-eng administrative-weight 20ip rsvp bandwidth 100000
!router isisnet 49.0001.1720.1625.5001.00is-type level-2-onlymetric-style widempls traffic-eng router-id Loopback0mpls traffic-eng level-2passive-interface Loopback0
!
11© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Configuring MPLS TE and Link Information Distribution Using OSPF (Cisco IOS)
Enable TE extensions (TE router id and area)
Enable MPLS TE on this node
Enable MPLS TE on this interfaceAttribute flagsTE metricMaximum reservable bandwidth
mpls traffic-eng tunnels!interface POS0/1/0ip address 172.16.0.0 255.255.255.254mpls traffic-eng tunnelsmpls traffic-eng attribute-flags 0xFmpls traffic-eng administrative-weight 20ip rsvp bandwidth 100000
!router ospf 100log-adjacency-changespassive-interface Loopback0network 172.16.0.0 0.0.255.255 area 0mpls traffic-eng router-id Loopback0mpls traffic-eng area 0
!
12© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Configuring MPLS TE and Link Information Distribution Using IS-IS (Cisco IOS XR)
Enable wide metric format and TE extensions (TE Id, router level)
Attribute flags
TE metric
Configuration mode for RSVP global and interface commands
Maximum reservable bandwidth
Configuration mode for MPLS TE global and interface commands
router isis DEFAULTis-type level-2-onlynet 49.0001.1720.1625.5129.00address-family ipv4 unicastmetric-style widempls traffic-eng level 2mpls traffic-eng router-id Loopback0
!interface Loopback0passiveaddress-family ipv4 unicast!
!interface POS0/3/0/0address-family ipv4 unicast!
!!rsvpinterface POS0/3/0/0bandwidth 100000
!!mpls traffic-enginterface POS0/3/0/0admin-weight 5attribute-flags 0x8
!!
13© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Configuring MPLS TE and Link Information Distribution Using OSPF (Cisco IOS XR)
Attribute flags
TE metric
Configuration mode for RSVP global and interface commands
Maximum reservable bandwidth
Configuration mode for MPLS TE global and interface commands
router ospf DEFAULTarea 0mpls traffic-enginterface Loopback0passive !interface POS0/3/0/0!
mpls traffic-eng router-id Loopback0 !rsvpinterface POS0/3/0/0bandwidth 100000
!!mpls traffic-enginterface POS0/3/0/0admin-weight 5attribute-flags 0x8
!!
TE router Id
Enable TE extensions on this area
14© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Configuring Tunnel at Head End (Cisco IOS)
Tunnel path options (PATH1, otherwise dynamic)
Destination (tunnel tail end)
TE tunnel (as opposed to GRE or others)
Setup/hold priorities
Signaled bandwidth
Explicit PATH1 definition
interface Tunnel1description FROM-ROUTER-TO-DST1ip unnumbered Loopback0tunnel destination 172.16.255.3tunnel mode mpls traffic-engtunnel mpls traffic-eng priority 5 5tunnel mpls traffic-eng bandwidth 10000tunnel mpls traffic-eng affinity 0x0 mask 0xFtunnel mpls traffic-eng path-option 5 explicit name PATH1tunnel mpls traffic-eng path-option 10 dynamic
!ip explicit-path name PATH1 enablenext-address 172.16.0.1next-address 172.16.8.0
!
Consider links with 0x0/0xF as attribute flags
15© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Configuring Tunnel at Head End (Cisco IOS XR)
Tunnel path options (PATH1, otherwise dynamic)
Destination (tunnel tail end)
Setup/hold priorities
Signaled bandwidth
Explicit PATH1 definition
explicit-path name PATH1index 1 next-address ipv4 unicast 172.16.0.4index 2 next-address ipv4 unicast 172.16.0.7index 3 next-address ipv4 unicast 172.16.4.2
!interface tunnel-te1description FROM-ROUTER-TO-DST1ipv4 unnumbered Loopback0priority 5 5signalled-bandwidth 100000destination 172.16.255.2path-option 10 explicit name PATH1path-option 20 dynamicaffinity f mask f
!
Consider links with 0xF/0xF as attribute flags
16© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
MPLS TE and L2/L3VPN
Ethernet
IP/MPLS
CE CE
CECE Ethernet
TE LSP with Reserved BW
L2VPN (Pseudowire)
Low-Latency, BW Protected TE LSP
Layer 3 VPN Service
ATM
Frame Relay
ATMCE CE
CE
CE Ethernet
CE
CE
TE LSPs provide transport for other services
PEPE
PEPE
PEPE
17© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
R2
R1
R8
IP/MPLS
R2
R1
R8
IP/MPLS
R2
R1
R8
IP/MPLS
R2
R1
R8
IP/MPLS
MPLS TE Deployment ModelsBandwidth Optimization
Strategic Tactical
Protection Point-to-Point SLA
18© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Bandwidth Optimization
19© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Strategic Bandwidth Optimization
Tries to optimize underlying physical topology based on traffic matrix
Key goal is to avoid link over/under utilization
On-line (CSPF) or off-line path computation
May result in a significant number of tunnels
R1 R2 R3 R4 R5 R6R1 4 7 1 5 4 5
R2 2 2 4 7 2 3
R3 1 2 9 5 5 5
R4 9 1 4 1 3 1
R5 3 7 9 2 7 7
R6 6 3 5 4 9 12
R1
R2
R3
R6
R5
R4
R1
R2
R3
R6
R5
R4
Traffic MatrixPhysical Topology Tunnel mesh to satisfy
traffic matrix
20© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Traffic Matrix Measurement
Unconstrained tunnels
Interface MIB
MPLS LSR MIB
NetFlowNetFlow BGP Next Hop
MPLS-Aware NetFlow
Egress/Output NetFlow
BGP policy accountingCommunities
AS path
IP prefix
P
P
PE
PE
POP
PE
Server Farm
Server Farm
AS65001
PE
PE
PE
P
P
POP
AS65002 AS65003
Measuring Internal and External Traffic Matrix
21© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
AutoTunnel Mesh
Mesh group: LSRs to mesh automatically
Membership identified byMatching TE Router ID against ACL
IGP mesh-group advertisement
Each member automatically creates tunnel upon detection of a member
Tunnels instantiated from template
Individual tunnels not displayed in router configuration
New mesh group
member
New mesh group
member
22© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Auto Bandwidth
Dynamically adjust bandwidth reservation based on measured traffic
Optional minimum and maximum limits
Sampling and resizing timers
Tunnel resized to largest sample since last adjustment
Min
Max
Total bandwidthfor all TE tunnelson a path
Bandwidthavailable to other tunnels
Tunnel resized tomeasured rate
Time
23© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Configuring AutoTunnel Mesh (Cisco IOS)
Enable Auto-tunnel Mesh
Template cloned for each member of mesh group 10
Tunnel template
Dynamic (CSPF) path to each mesh group member
Advertise mesh group 10 membership in area 0
Tunnels will adjust bandwidth reservation automatically
mpls traffic-eng tunnelsmpls traffic-eng auto-tunnel mesh!interface Auto-Template1ip unnumbered Loopback0tunnel destination mesh-group 10tunnel mode mpls traffic-engtunnel mpls traffic-eng autoroute announcetunnel mpls traffic-eng path-option 10 dynamictunnel mpls traffic-eng auto-bw frequency 3600
! router ospf 16log-adjacency-changesmpls traffic-eng router-id Loopback0mpls traffic-eng area 0mpls traffic-eng mesh-group 10 Loopback0 area 0passive-interface Loopback0network 172.16.0.0 0.0.255.255 area 0!
24© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Tactical Bandwidth Optimization
Selective deployment of tunnels when highly-utilized links are identified
Generally, deployed until next upgrade cycle alleviates affected links
R2
R1
R8
IP/MPLS
R2
R1
R8
IP/MPLS
Strategic TacticalBandwidth Optimization
25© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Traffic Protection
26© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Traffic Protection Using MPLS TE Fast Re-Route (FRR)
Subsecond recovery against node/link failures
Scalable 1:N protection
Greater protection granularity
Cost-effective alternative to 1:1 protection
Bandwidth protection
Primary TE LSP
Backup TE LSP
IP/MPLS
R2
R1
R8
27© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
FRR Link Protection Operation
Requires next-hop (NHOP) backup tunnel
Point of Local Repair (PLR) swaps label and pushes backup label
Backup terminates on Merge Point (MP) where traffic rejoins primary
Restoration time expected under ~50 ms
Primary TE LSP
Backup TE LSP
IP/MPLS
R1
25252222
1616 2222
2222
R2 R6 R7
R3
R5
28© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
FRR Node Protection Operation
Requires next-next-hop(NNHOP) backup tunnel
Point of Local Repair (PLR) swaps next-hop label and pushes backup label
Backup terminates on Merge Point (MP) where traffic rejoins primary
Restoration time depends on failure detection time
Primary TE LSP
Backup TE LSP
IP/MPLS
R1
25253636
1616 2222
3636
R2 R5 R6
R3
R4
3636
R5
29© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Bandwidth Protection
Backup tunnel with associated bandwidth capacity
Backup tunnel may or may not actually signal bandwidth
PLR will decide best backup to protect primary (nhop/nnhop, backup-bw, class-type, node-protection flag)
Primary TE LSP
Backup TE LSP
IP/MPLS
R1 R2 R5 R6
R3
R4
R5
30© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
AutoTunnel: Primary Tunnels What’s the Problem?
FRR can protect TE Traffic
No protection mechanism for IP or LDP traffic
How to leverage FRR for all traffic?
What if protection desired without traffic engineering?
Primary TE LSP
Backup TE LSP
IP/MPLS
R2
R1
R8
31© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
AutoTunnel: Primary Tunnels What’s the Solution?
Create protected one-hop tunnels on all TE links
Priority 7/7Bandwidth 0Affinity 0x0/0xFFFFAuto-BW OFFAuto-Route ONFast-Reroute ONForwarding-Adj OFFLoad-Sharing OFF
Tunnel interfaces not shown on router configurationConfigure desired backup tunnels (manually or automatically)
Primary TE LSP
IP/MPLS
R2
R1
R8
Forward all traffic through a one- hop protected primary TE tunnel
32© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
AutoTunnel: Primary Tunnels Why One-Hop Tunnels?
CSPF and SPF yield same results (absence of tunnel constraints)
Auto-route forwards all traffic through one-hop tunnel
Traffic logically mapped to tunnel but no label imposed (imp-null)
traffic is forwarded as if no tunnel was in place
Primary TE LSP
IP/MPLS
R2
R1
R8
33© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Configuring AutoTunnel Primary Tunnels (Cisco IOS)
Enable auto- tunnel primary
Range for tunnel interfaces
mpls traffic-eng tunnels
mpls traffic-eng auto-tunnel primary onehop
mpls traffic-eng auto-tunnel primary tunnel-num min 900 max 999
!
34© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
AutoTunnel: Backup Tunnels What’s the Problem?
MPLS FRR requires backup tunnels to be preconfigured
Automation of backup tunnels is desirable
Primary TE LSP
Backup TE LSP
IP/MPLS
R2
R1
R8
35© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
AutoTunnel: Backup Tunnels What’s the Solution?
Detect if a primary tunnel requires protection and is not protected
Verify that a backup tunnel doesn’t already exist
Compute a backup path to NHOP and NHOP excluding the protected facility
Optionally, consider shared risk link groups during backup path computation
Signal the backup tunnelsPrimary TE LSP
Backup TE LSP
IP/MPLS
R2
R1
R8
Create backup tunnels automatically as needed
36© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
AutoTunnel: Backup Tunnels What’s the Solution? (Cont.)
Backup tunnels are preconfigured
Priority 7/7
Bandwidth 0
Affinity 0x0/0xFFFF
Auto-BW OFF
Auto-Route OFF
Fast-Reroute OFF
Forwarding-Adj OFF
Load-Sharing OFF
Backup tunnel interfaces and paths not shown on router configuration
Primary TE LSP
Backup TE LSP
IP/MPLS
R2
R1
R8
37© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Configuring AutoTunnel Backup Tunnels (Cisco IOS)
Enable auto- tunnel backup (NHOP tunnels only)
Tear down unused backup tunnels
Range for tunnel interfaces
Consider SRLGs preferably
mpls traffic-eng tunnels
mpls traffic-eng auto-tunnel backup nhop-only
mpls traffic-eng auto-tunnel backup tunnel-num min 1900 max 1999
mpls traffic-eng auto-tunnel backup timers removal unused 7200
mpls traffic-eng auto-tunnel backup srlg exclude preferred
!
38© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Shared Risk Link Group (SRLG)
Some links may share same physical resource (e.g. fiber, conduit)
AutoTunnel Backup can force or prefer exclusion of SRLG to guarantee diversely routed backup tunnels
IS-IS and OSPF flood SRLG membership as an additional link attribute
IP/MPLSIP/MPLS
R1R1 R5R5
R2R2 R4R4
R3R3
IP/MPLSIP/MPLS
R1R1 R5R5
R2R2 R4R4
R3R3
SRLG 10R2-R4 R2-R3
SRLG 20R4-R2R4-R3
SRLG 30R3-R2R3-R4
SRLG 10R2-R4 R2-R3
SRLG 20R4-R2R4-R3
SRLG 30R3-R2R3-R4
Layer-3 Topology Layer-3 Plus Physical Topology
39© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Bidirectional Forwarding Detection Trigger for FRR
Primary TE LSP
Backup TE LSP
IP/MPLS
R2
R1
R8
FRR relies on quick PLR failure detection
Some failures may not produce loss of signal or alarms on a link
BFD provides light-weight neighbor connectivity failure
BFD session
40© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
What About Path Protection?
Primary and backup share head and tail, but diversely routed
Expected to result in higher restoration times compared to local protection
Doubles number of TE LSPs (1:1 protection)
May be an acceptable solution for restricted topologies (e.g. rings)
http://www.cisco.com/go/mpls
Primary TE LSP
Backup TE LSP
IP/MPLS
R2
R1
R8
41© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
TE for QoS
42© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Motivations
Point-to-point SLAs
Admission control
Integration with DiffServ
Increased routing control to improve network performance
PE2
PE1
PE3
IP/MPLS
43© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Service Differentiation
Resource Optimization
Network with MPLS TE
A solution when:No differentiation required
Optimization required
Full mesh or selective deployment to avoid over-subscription
Increased network utilization
Adjust link load to actuallink capacity
Load Capacity
TE
44© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Class3
Service Differentiation
Resource Optimization
Network with MPLS DiffServ and MPLS TE
A solution when:Differentiation required
Optimization required
Adjust class capacity to expected class load
Adjust class load to actual class capacity for one class
Alternatively, adjust link load to actual link capacity
DiffServ+
TE
Load CapacityClass1
Class2
Load Capacity
Load Capacity
45© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Class3
Service Differentiation
Resource Optimization
Network with MPLS DiffServ and MPLS DS-TE
A solution when:Strong differentiation required
Fine optimization required
Adjust class capacity to expected class load
Adjust class load to actual class capacity
DiffServ+
DS-TE
LoadClass1
Load Capacity
Capacity
Class2
CapacityLoad
46© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
DiffServ-Aware Traffic Engineering
IS-IS or OSPF flood link information (as usual)Per-class unreserved bandwidth on each linkNew RSVP object (CLASSTYPE)Nodes manages link bandwidth using a bandwidth constraint modelTwo models defined
Maximum Allocation Model (MAM)Russian Doll Model (RDM)
Unique class definition and constraint model throughout networkTwo classes (class-types) in current implementations
PE2
PE1
PE3
IP/MPLS
Class-type 1 (voice) 20%
Class-type 2 (video) 40%
Bandwidth Constraints
47© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Pre-standard DS-TE Implementation
Only supports Russian Dolls Model (RDM) for bandwidth constraints
No changes to RSVP-TE specs to signal desired pool (leverages ADSPEC object in PATH messages)
Sub-pool TE LSPs signaled as guaranteed service
Global pool TE LSPs signaled as controlled-load service
Modified OSPF-TE and ISIS-TE advertisementsto include two pools at 8 priority levels each (16 entries per link total)
Available on IOS and IOS XR
48© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
What Is New in IETF DS-TE Implementation?
Supports both RDM and MAM (Maximum Allocation Model) for bandwidth constraintsNew CLASSTYPE object in RSVP-TE to signal desired class-type (unused by “class-type 0” for backward compatibility with non-DS-TE)Minor Changes to OSPF-TE and ISIS-TE bandwidth advertisements
Same “unreserved bandwidth” sub-TLV (8 entries) as non-DS-TE interpreted according to local definition of TE-Class (class-type/preemption priority)New BC sub-TLV
Operates in migration or IETF mode in Cisco IOSDeveloped simultaneously for IOS and IOS XR
49© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
TE-Class Definition Examples
Priority 0 Priority 1 Priority 2 Priority 3 Priority 4 Priority 5 Priority 6 Priority 7CT0 (Global) TE-Class0 TE-Class1 TE-Class2 TE-Class3 TE-Class4 TE-Class5 TE-Class5 TE-Class7CT1 (Sub)
Priority 0 Priority 1 Priority 2 Priority 3 Priority 4 Priority 5 Priority 6 Priority 7CT0 (Global) TE-Class4 TE-Class0CT1 (Sub) TE-Class5 TE-Class1
Priority 0 Priority 1 Priority 2 Priority 3 Priority 4 Priority 5 Priority 6 Priority 7CT0 (Global) TE-Class4 TE-Class5 TE-Class6 TE-Class7CT1 (Sub) TE-Class0 TE-Class1 TE-Class2 TE-Class3
Default TE-Class definition
TE-Class definition compatible with non-DS-TE
Priority 0 Priority 1 Priority 2 Priority 3 Priority 4 Priority 5 Priority 6 Priority 7CT0 (Global) TE-Class1 TE-Class3 TE-Class5 TE-Class7CT1 (Sub) TE-Class0 TE-Class2 TE-Class4 TE-Class6
User-defined TE-Classes with no preemption between class-types
User-defined TE-Classes with preemption between/within class-types
TE-Class definition MUST be consistent throughout the network
50© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
All Classes
Maximum Allocation Model (MAM)
BW pool applies to one class
Sum of BW pools may exceed MRB
Sum of total reserved BW may not exceed MRB
Current implementation supports BC0 and BC1
Maximum Reservable Bandwidth
(MRB)
BC2
BC1
BC0
Class1
Class0
Class2
51© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Russian Dolls Model (RDM)
BW pool applies to one or more classes
Global BW pool (BC0) equals MRB
BC0..BCn used for computing unreserved BW for class n
Current implementation supports BC0 and BC1
BC2
BC1
BC0All
Classes
(Class0 +
Class1 +
Class2)Class1 +
Class2Class2
Maximum Reservable Bandwidth
(MRB)
52© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
MAM vs. RDM
MAM RDMOne BC per CT One or more CTs per BC
Sum of all BCs may exceed maximum reservable bandwidth
BC0 always equals to maximum reservable bandwidth
Preemption not required to provide bandwidth guarantees per CT
Preemption required to provide bandwidth guarantees per CT
Bandwidth efficiency and protection against QoS degradation are mutually exclusive
Provides bandwidth efficiency and protection against QoS degradation simultaneously
53© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Dst3
Class-Based Tunnel Selection: CBTS
EXP-based selection between multiple tunnels to same destinationLocal mechanism athead-endTunnels configured with EXP values to carryTunnels may be configured as defaultNo IGP extensionsSupports VRF traffic, IP-to-MPLS and MPLS-to-MPLS switchingSimplifies use of DS-TE tunnels
Tunnel1Tunnel2
Tunnel3
Tunnel5
Tunnel6Tunnel7
Dst1
Dst2
Dst1, exp 5 Tunnel1Dst1, * Tunnel2Dst2, exp 5 Tunnel3Dst2, exp 2 Tunnel4Dst2, * Tunnel5Dst3, exp 5 Tunnel6Dst3, * Tunnel7
Tunnel4
FIB
*Wildcard EXP Value
54© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Inter-domain Traffic Engineering
55© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Inter-Domain Traffic Engineering: Introduction
Domain defined as an IGP area or autonomous system
Head end lacks complete network topology to perform path computation in both cases
Two path computation approachesPer-domain (ERO loose-hop expansion)
Distributed (Path Computation Element)
http://www.cisco.com/go/mpls
56© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
ERO ERO
Per-Domain Path Computation Using ERO Loose-hop Expansion
IP/MPLS ASBR1 ASBR2 IP/MPLS
R1 R7
ASBR3 ASBR4
ASBR4 (Loose) R7 (Loose)
R2
R3
R4
R5
R6
R3, ASBR3, ASBR4R7 (Loose)
R5, R7R7 (Loose)
R1 Topology database
ASBR4 Topology database
ERO EROexpansion expansion
Inter-AS TE LSP
57© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Inter-Domain TE – TE LSP Reoptimization
Reoptimization can be timer/event/admin triggered
Head end sets ‘path re-evaluation request’ flag (SESSION_ATTRIBUTE)
Head end receives PathErr message notification from boundary router if a preferable path exists
Make-before-break TE LSP setup can be initiated after PathErrnotification
IP/MPLS ASBR1 ASBR2 IP/MPLS
R1 R7
ASBR3 ASBR4
R2
R3
R4
R5
R6 Inter-AS TE LSP after
reoptimization
Inter-AS TE LSP before
reoptimization
Make before break
Path re-evaluation request Preferable
Path exists
PATHPathErr
58© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Inter-Domain TE – Fast Re-route
Same configuration as single domain scenario
Support for node-id sub-object required to implement ABR/ASBR node protection
Node-id helps point of local repair (PLR) detect a merge point (MP)
IP/MPLS ASBR1 ASBR2 IP/MPLS
R1 R7
ASBR3 ASBR4
R2
R3
R4
R5
R6
Primary TE LSPBackup TE LSP
59© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Inter-Domain TE – Authentication and Policy Control
Authentication and policy control desirable for Inter-AS deployments
ASBR may perform RSVP authentication (MD5/SHA-1)
ASBR may enforce a local policy for Inter-AS TE LSPs (e.g. limit bandwidth, message types, protection, etc.)
IP/MPLS ASBR1 ASBR2 IP/MPLS
R1 R7
ASBR3 ASBR4
R2
R3
R4
R5
R6
Inter-AS TE LSP
Policy
60© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Distributed Path Computation using Path Computation Element
Path1 (cost 300): ABR2, R4, R6 R7
IP/MPLS ABR1 ABR2 IP/MPLS
R1 R7
ABR3 ABR4
R2
R3
R4
R5
R6
TE LSP
Path Computation Element
IP/MPLS
Area 0 Area 3Area 1
Path Computation ReplyPath Computation Request
ABR2 Topology database
(area 3)
Path2 (cost 200): ABR4, R5, R7
Path1 (cost 400): ABR1, ABR2, R4, R6 R7
Path2 (cost 300): ABR3, ABR4, R5, R7
Virtual Shortest
Path Tree
ABR1 Topology database
(area 0)
Virtual Shortest
Path Tree
R1 Topology database
Path (cost 500): R3, ABR3, ABR4, R5, R7
Backward Recursive PCE-based Computation (BRPC)
ABR1 ABR2R1
61© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Distributed Path Computation with Backward Recursive PCE-based Computation (BRPC)
Head-end sends request to a path computation element (PCE)
PCE recursively computes virtual shortest path tree (SPT) to destination
Head-end receives reply with virtual SPT if a path exists
Head-end uses topology database and virtual SPT to compute end-to-end path
Head-end can discover PCEs dynamically or have them configured statically
62© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Configuring PCE (Cisco IOS XR)
PCE
Headendinterface tunnel-te1description FROM-ROUTER-TO-DST2ipv4 unnumbered Loopback0destination 172.16.255.1path-option 10 dynamic pce
!router staticaddress-family ipv4 unicast172.16.255.1/32 tunnel-te1
!!
mpls traffic-engpce deadtimer 30pce address ipv4 172.16.255.129pce keepalive 10
!
Use discovered PCEs for path computation
Static route mapping IP traffic to tunnel-te1
Declare peer down if no keepalive in 30s
Advertise PCE capability with address 172.16.255.129
Send per keepalive every 10s
63© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Inter-Domain TE Take into Account before Implementing
Semantics of link attributes across domain boundaries
Semantics of TE-Classes across domain boundaries for DS-TE
Auto-route not possible for traffic selection
64© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
General Deployment Considerations
65© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Should RSVP-TE and LDP be Used Simultaneously?
Guarantees forwarding of VPN traffic if a TE LSP fails
May be required if full mesh of TE LSPs not in use
Increased complexity
http://www.cisco.com/go/mpls
66© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
12 TE LSP
56 TE LSP
PE
PE
PE
PE
PE
PE
PE
PE
How Far should Tunnels Span?
PE-to-PE TunnelsMore granular control on traffic forwarding
Larger number of TE LSPs
P-to-P TunnelsRequires IP tunnels or LDP over TE tunnels to carry VPN traffic
Fewer TE LSPs
PE
PE
PE
PE
PE
PE
PE
PE
P
P
P
P
67© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Scaling Signaling (Refresh Reduction)
Message Identifier associated with Path/Resv state
Summary Refresh (SRefresh) message with message_id list to refresh soft state
SRefresh only replaces refresh Path/Resv messages
http://www.cisco.com/go/mpls
MSG_Id Path State
LSP1 22 …LSP2 62 …
. . …LSPn 94 …
MSG_Id Resv State
LSP1 43 …LSP2 37 …
. . …LSPn 29 …
SRefresh Message
Msg_id list
Msg_id list
68© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Let’s Summarize
69© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Summary
Technology OverviewExplicit and constrained- based routing
TE protocol extensions (OSPF, ISIS and RSVP)
Bandwidth optimizationStrategic (full mesh, auto-tunnel)
Tactical
Traffic ProtectionLink/node protection (auto-tunnel)
Bandwidth protection
TE for QoSDS-TE (MAM, RDM)
CBTS
Inter-Domain Traffic Engineering
Inter-Area
Inter-AS (Authentication, policy control)
General Deployment Considerations
MPLS TE and LDP
PE-to-PE vs. P-to-P tunnels
Scaling signalinghttp://www.cisco.com/go/mpls
70© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Recommended Reading
Continue your Networkers at Cisco Live learning experience with further reading from Cisco Press
Check the Recommended Reading flyer for suggested books
Available on site at the Cisco Company Store
71© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Recommended Reading
Continue your Networkers at Cisco Live learning experience with further reading from Cisco Press
Check the Recommended Reading flyer for suggested books
Available on site at the Cisco Company Store
72© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Recommended Reading
Continue your Networkers at Cisco Live learning experience with further reading from Cisco Press
Check the Recommended Reading flyer for suggested books
Available on site at the Cisco Company Store
73© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Q and A
74© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Complete Your Online Session Evaluation
Win fabulous prizes; Give us your feedback
Receive ten Passport Points for each session evaluation you complete
Go to the Internet stations located throughout the Convention Center to complete your session evaluation
Drawings will be held in the World of Solutions
Tuesday, June 20 at 12:15 p.m.
Wednesday, June 21 at 12:15 p.m.
Thursday, June 22 at 12:15 p.m. and 2:00 p.m.
75© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Backup Slides
76© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Configuring FRR (Cisco IOS)
Indicate the desire for local protection during signaling
interface Tunnel1description FROM-ROUTER-TO-DST1-FRRip unnumbered Loopback0tunnel destination 172.16.255.2tunnel mode mpls traffic-engtunnel mpls traffic-eng bandwidth 20000tunnel mpls traffic-eng path-option 10 dynamictunnel mpls traffic-eng fast-reroute
!
Use Tunnel1 as backup for protected LSPs through POS1/0/0
Explicitly routed backup to 172.16.255.2 with zero bandwidth
interface Tunnel1description NNHOP-BACKUPip unnumbered Loopback0tunnel destination 172.16.255.2tunnel mode mpls traffic-engtunnel mpls traffic-eng path-option 10 explicit name PATH1
!interface POS1/0/0ip address 172.16.192.5 255.255.255.254mpls traffic-eng tunnelsmpls traffic-eng backup-path Tunnel1ip rsvp bandwidth
!
Primary Tunnel
Backup Tunnel
77© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Configuring FRR (Cisco IOS XR)
interface tunnel-te1description FROM-ROUTER-TO-DST1-FRRipv4 unnumbered Loopback0signalled-bandwidth 30000destination 172.16.255.2fast-reroutepath-option 10 dynamic
!
Indicate the desire for local protection during signaling
Primary Tunnel
Backup Tunnelinterface tunnel-te1description NHOP-BACKUPipv4 unnumbered Loopback0destination 172.16.255.130path-option 10 explicit name PATH1
!mpls traffic-enginterface POS0/3/0/0backup-path tunnel-te 1
!!
Use tunnel-te1 as backup for protected LSPs through POS0/3/0/0
Explicitly routed backup to 172.16.255.130 with zero bandwidth
78© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Configuring SRLG (Cisco IOS)
Force SRLG exclusion during backup path computation
Interface member of SRLG 15 and 25
Interface member of SRLG 25
mpls traffic-eng tunnels
mpls traffic-eng auto-tunnel backup nhop-only
mpls traffic-eng auto-tunnel backup srlg exclude force
!
interface POS0/1/0
ip address 172.16.0.0 255.255.255.254
mpls traffic-eng tunnels
mpls traffic-eng srlg 15
mpls traffic-eng srlg 25
ip rsvp bandwidth
!
interface POS1/0/0
ip address 172.16.0.2 255.255.255.254
mpls traffic-eng tunnels
mpls traffic-eng srlg 25
ip rsvp bandwidth
!
79© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Configuring DS-TE Classes and Bandwidth Constraints (Cisco IOS)
MAM
RDMmpls traffic-eng tunnelsmpls traffic-eng ds-te mode ietfmpls traffic-eng ds-te te-classeste-class 0 class-type 1 priority 0te-class 1 class-type 1 priority 1te-class 2 class-type 1 priority 2te-class 3 class-type 1 priority 3te-class 4 class-type 0 priority 4te-class 5 class-type 0 priority 5te-class 6 class-type 0 priority 6te-class 7 class-type 0 priority 7
!interface POS0/1/0ip address 172.16.0.0 255.255.255.254mpls traffic-eng tunnelsip rsvp bandwidth rdm bc0 155000 bc1 55000
!
mpls traffic-eng tunnelsmpls traffic-eng ds-te mode ietfmpl traffic-eng ds-te bc-model mam!interface POS0/1/0ip address 172.16.0.0 255.255.255.254mpls traffic-eng tunnelsip rsvp bandwidth mam max-reservable-bw 155000 bc0 100000 bc1 55000
!
Enable IETF DS-TE
RDM bandwidth constraints
Explicit TE- Class definition
Enable IETF DS-TE and use default TE- Class definition
MAM bandwidth constraints
Enable MAM
80© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Configuring DS-TE Tunnel (Cisco IOS)
Signal Tunnel1 with CT0 (priority and CT must match valid TE-Class)
Signal Tunnel2 with CT1 (priority and CT must match valid TE-Class)
interface Tunnel1
description FROM-ROUTER-TO-DST1-CT0
ip unnumbered Loopback0
no ip directed-broadcast
tunnel destination 172.16.255.3
tunnel mode mpls traffic-eng
tunnel mpls traffic-eng priority 5 5
tunnel mpls traffic-eng bandwidth 100000 class-type 0
tunnel mpls traffic-eng path-option 10 dynamic
!
interface Tunnel2
description FROM-ROUTER-TO-DST1-CT1
ip unnumbered Loopback0
no ip directed-broadcast
tunnel destination 172.16.255.3
tunnel mode mpls traffic-eng
tunnel mpls traffic-eng priority 0 0
tunnel mpls traffic-eng bandwidth 50000 class-type 1
tunnel mpls traffic-eng path-option 10 dynamic
!
81© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Configuring DS-TE Classes and Bandwidth Constraints (Cisco IOS XR)
MAM
RDMrsvpinterface POS0/3/0/0bandwidth rdm bc0 155000 bc1 55000!!mpls traffic-enginterface POS0/3/0/0!ds-te mode ietfds-te te-classeste-class 0 class-type 1 priority 0te-class 1 class-type 1 priority 1te-class 2 class-type 1 priority 2te-class 3 class-type 1 priority 3te-class 4 class-type 0 priority 4te-class 5 class-type 0 priority 5te-class 6 class-type 0 priority 6te-class 7 class-type 0 priority 7!!
rsvpinterface POS0/3/0/0bandwidth mam max-reservable-bw 155000 bc0 100000 bc1 55000!!mpls traffic-enginterface POS0/3/0/0!ds-te mode ietfds-te bc-model mam!
RDM bandwidth constraints
Enable IETF DS-TE
Explicit TE- Class definition
Enable IETF DS-TE and use default TE- Class definition
MAM bandwidth constraints
Enable MAM
82© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Configuring DS-TE Tunnels (Cisco IOS XR)
Signal tunnel- te1 with CT0 (priority and CT must match valid TE-Class)
Signal tunnel- te2 with CT1 (priority and CT must match valid TE-Class)
interface tunnel-te1
description FROM-ROUTER-TO-DST1-CT0
ipv4 unnumbered Loopback0
priority 5 5
signalled-bandwidth 100000 class-type 0
destination 172.16.255.2
path-option 10 dynamic
!
interface tunnel-te2
description FROM-ROUTER-TO-DST1-CT1
ipv4 unnumbered Loopback0
priority 0 0
signalled-bandwidth 50000 class-type 1
destination 172.16.255.2
path-option 10 dynamic
!
83© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Configuring CBTS (Cisco IOS)
interface Tunnel1ip unnumbered Loopback0tunnel destination 172.16.255.3tunnel mode mpls traffic-engtunnel mpls traffic-eng priority 5 5tunnel mpls traffic-eng bandwidth 10000tunnel mpls traffic-eng path-option 10 dynamictunnel mpls traffic-eng exp 5
! interface Tunnel2ip unnumbered Loopback0tunnel destination 172.16.255.3tunnel mode mpls traffic-engtunnel mpls traffic-eng path-option 10 dynamictunnel mpls traffic-eng exp default
!ip route 192.168.0.0 255.255.255.0 Tunnel1ip route 192.168.0.0 255.255.255.0 Tunnel2!
Tunnel2 will carry packets with MPLS EXP other than 5
Tunnel1 will carry packets with MPLS EXP 5
CBTS performed on prefix 192.168.0.0/24 using Tunnel1 and Tunnel2
84© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Configuring Inter-Area Tunnels (Cisco IOS)
Loose-hop path
List of ABRs as loose hops
mpls traffic-eng tunnels
!
interface Tunnel1
ip unnumbered Loopback0
no ip directed-broadcast
tunnel destination 172.16.255.7
tunnel mode mpls traffic-eng
tunnel mpls traffic-eng path-option 10 explicit name LOOSE-PATH
!
ip route 172.16.255.7 255.255.255.255 Tunnel1
!
ip explicit-path name LOOSE-PATH enable
next-address loose 172.16.255.3
next-address loose 172.16.255.5
!
Static route mapping IP traffic to Tunnel1
85© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Configuring Inter-Area Tunnels (Cisco IOS XR)
explicit-path name LOOSE-PATH
index 1 next-address loose ipv4 unicast 172.16.255.129
index 2 next-address loose ipv4 unicast 172.16.255.131
!
interface tunnel-te1
description FROM-ROUTER-TO-DST3
ipv4 unnumbered Loopback0
destination 172.16.255.2
path-option 10 explicit name LOOSE-PATH
!
router static
address-family ipv4 unicast
172.16.255.2/32 tunnel-te1
!
Static route mapping IP traffic to tunnel-te1
Loose-hop path
List of ABRs as loose hops
86© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Configuring Inter-AS Tunnels (Cisco IOS)
Loose-hop path
List of ASBRs as loose hops
Static route mapping IP traffic to Tunnel1
mpls traffic-eng tunnels
!
interface Tunnel1
ip unnumbered Loopback0
no ip directed-broadcast
tunnel destination 172.31.255.5
tunnel mode mpls traffic-eng
tunnel mpls traffic-eng priority 7 7
tunnel mpls traffic-eng bandwidth 1000
tunnel mpls traffic-eng path-option 10 explicit name LOOSE-PATH
!
ip route 172.31.255.5 255.255.255.255 Tunnel1
!
ip explicit-path name LOOSE-PATH enable
next-address loose 172.24.255.1
next-address loose 172.31.255.1
!
87© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Configuring Inter-AS TE at ASBR (Cisco IOS)
Process signaling from AS 65016 if FRR not requested and 10M or less
Add ASBR link to TE topology database
Authentication key
Enable RSVP authentication
mpls traffic-eng tunnels!key chain A-ASBR1-keykey 1 key-string 7 151E0E18092F222A
!interface Serial1/0ip address 192.168.0.1 255.255.255.252mpls traffic-eng tunnelsmpls traffic-eng passive-interface nbr-te-id 172.16.255.4 nbr-igp-id ospf 172.16.255.4ip rsvp bandwidthip rsvp authentication key-chain A-ASBR1-keyip rsvp authentication type sha-1ip rsvp authentication!router bgp 65024no synchronizationbgp log-neighbor-changesneighbor 172.24.255.3 remote-as 65024neighbor 172.24.255.3 update-source Loopback0neighbor 192.168.0.2 remote-as 65016no auto-summary!ip rsvp policy local origin-as 65016no fast-reroutemaximum bandwidth single 10000forward all!
88© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Configuring MPLS TE and LDP Simultaneously (Cisco IOS)
Enable LDP
Enable MPLS forwarding for IP (LDP)
Enable MPLS TE on interface
Enable MPLS TE
mpls label protocol ldp
mpls traffic-eng tunnels
!
interface POS0/1/0
ip address 172.16.0.0 255.255.255.254
mpls traffic-eng tunnels
mpls ip
ip rsvp bandwidth 155000
!
89© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Configuring MPLS TE and LDP Simultaneously (Cisco IOS XR)
rsvp
interface POS0/3/0/0
bandwidth 155000
!
!
mpls traffic-eng
interface POS0/3/0/0
!
!
mpls ldp
interface POS0/3/0/0
!
!
Configuration mode for RSVP global and interface commands
Configuration mode for MPLS TE global and interface commands
Configuration mode for LDP global and interface commands
90© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Configuring LDP Over a TE Tunnel (Cisco IOS)
x
mpls label protocol ldp
mpls traffic-eng tunnels
!
interface Tunnel1
ip unnumbered Loopback0
mpls ip
tunnel destination 172.16.255.3
tunnel mode mpls traffic-eng
tunnel mpls traffic-eng autoroute announce
tunnel mpls traffic-eng path-option 10 dynamic
!
Enable MPLS forwarding for IP (LDP) on Tunnel1
Enable LDP
91© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Configuring LDP Over a TE Tunnel (Cisco IOS XR)
interface tunnel-te1ipv4 unnumbered Loopback0priority 0 0signalled-bandwidth 80000autoroute announcedestination 172.16.255.130path-option 10 dynamic
!rsvpinterface POS0/3/0/1bandwidth 155000
!!mpls traffic-enginterface POS0/3/0/1!
!mpls ldpinterface POS0/3/0/0!interface tunnel-te1!
!
Enable LDP on tunnel-te1
92© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public
Configuring Refresh Reduction (Cisco IOS)
Enable refresh reduction
* Enabled by default in Cisco IOS XR
mpls traffic-eng tunnels
!
interface POS0/1/0
ip address 172.16.0.0 255.255.255.254
mpls traffic-eng tunnels
ip rsvp bandwidth 100000
!
router ospf 100
log-adjacency-changes
passive-interface Loopback0
network 172.16.0.0 0.0.255.255 area 0
mpls traffic-eng router-id Loopback0
mpls traffic-eng area 0
!
ip rsvp signalling refresh reduction
!
93© 2008 Cisco Systems, Inc. All rights reserved. Cisco Public