1 © 2001, cisco systems, inc. mpls architecture & operation peter tomsu senior consultant emea...
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1© 2001, Cisco Systems, Inc.
MPLSArchitecture & Operation
Peter TomsuSenior Consultant EMEA
ptomsu@cisco.com
2© 2001, Cisco Systems, Inc. 2© 2000, Cisco Systems, Inc.
• Scalability of IP Based Forwarding• MPLS Architecture - A New Paradigm• MPLS Building Blocks• MPLS Packet Forwarding & Label Switched Paths• Frame-mode MPLS - Label Assignment & Distribution• Cell-mode MPLS - Label Assignment & Distribution• Configuring MPLS
Agenda
3© 2001, Cisco Systems, Inc.
Scalability of IP Based Forwarding
3© 2000, Cisco Systems, Inc.
4MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
London London POP routerPOP router
IGP
IGP
IGP
IGP
IGP
Paris Paris Peering PointPeering Point
•Independent hop by hop forwarding
•decision based on layer-3 header of the incoming packet and
•routing algorithm output
Packet Forwarding - IP Networks
•Forwarding decision based solely on IP destination addressHop-by-hop connectionless destination-only paradigmNo end-to-end pathsNo QoS or Optimization
5MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
• Layer-3 overlay scheme across layer-2Usually point-to-point links (VCs)
connection orientedFull mesh for optimal routing
Packet Forwarding – Layer 3 Overlay
London London Core routerCore router
Paris Paris Core routerCore router
Munich Munich Core routerCore router
ATM BackboneATM Backbone
ATM Switch ATM Switch LondonLondon
ATM Switch ATM Switch ParisParis
ATM Switch ATM Switch MunichMunich
ATM PVCATM PVC
6MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
MPLS Architecture A New
Paradigm
7MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
MPLS – Multi Protocol Label Switching
“
”draft-ietf-mpls-framework
“The primary goal of the MPLS working group is to standardise a base technology that integrates the label swapping forwarding paradigm with network layer routing.
Label Swapping is expected to improve •price/performance of network layer routing
•scalability of the network layer
•provide greater flexibility in the delivery of (new) routing services
•new routing services can be added without changing the forwarding paradigm
8MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
MPLS Peer Model
OSPF, BGP
PNNIOSPF, BGP
Overlay Modeleg Classical IP, MPOA, NHRPRouters and Switches totally isolatedRouters have no idea of ATM TopoIP features must be approximately mapped into ATM
Peer Modeleg MPLSRouters and Switches totally integratedRouters & Switches share topologyIP features directly supported by ATM
9MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
London London POP routerPOP router
IGP
IGP
IGP
IGP
IGP
Paris Paris Peering PointPeering Point
Packet forwarding based on labels - no reclassification of packets
Label Swapping
Multi-protocol Label Switching
MPLS Concepts
Packets are classified on entry into the MPLS
domain
Classification can be based on IGP but could be
QOS, TE, etc..
10© 2001, Cisco Systems, Inc. 10© 2001, Cisco Systems, Inc.
MPLS Building Blocks
11MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
MPLS - IP Switching Service 1a. The Routed protocol (OSPF, IGRP,...) computes 1a. The Routed protocol (OSPF, IGRP,...) computes
the shortest path to destination within the corethe shortest path to destination within the core
3.LSR: Label Switch Router• switches packet based on
label - Label Swapping
4.The last MPLS router removes label
2. ELSR (Edge LSR):• Inbound router receives
packets• runs usual L3 services• adds labels to packets
1b. The LDP (Label Distribution Protocol) binds a label to every destination address
12MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
Forwarding ComponentForwarding Component
also referred to as the data planedata planeresponsible for forwarding packets/cells based on labels
uses a label forwarding database maintained by the label switch
MPLS Forwarding Component
Simple Label SwappingSimple Label Swapping
13MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
MPLS Control Component
Control ComponentControl Component
also referred to as the control planecontrol planeresponsible for creating and maintaining label forwarding
information (known as label bindingslabel bindings)forwarding information taken from the FIB label mappings distributed via
LabelLabel Distribution ProtocolDistribution Protocol
The IntelligenceThe Intelligence
14MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
Cisco Express Forwarding
• Each LSR must have CEFCEF enabled globallyFIBFIB = Forwarding Information Baseonly IOS layer-3 switching method that uses the FIB tablewhen FIB entry created, label information is taken from the LIB
• Any interface that will perform label imposition must also have CEF enabled
as label imposition references the FIB
15MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
MPLS Specific Tables
• Each LSR will use a LIBLIB Label Information BaseLabel Information Base
Contains all label/prefix mappings from all TDP/LDP neighbours
• Each LSR will also use a LFIBLFIBLabel Forwarding Information Base
Contains only label/prefix mappings that are currently in use for label forwarding
16MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
Control-Plane to Data-Plane
Data plane in a nodeData plane in a node
IP Routing ProtocolIP Routing Protocol
IP Routing TableIP Routing TableC
o ntr o
l pl a
n e i n
a n
ode
Co n
tr ol p
l an e
i n a
nod
e
RouterRouter
IGPIGPRouting information
exchange with other routers
IP IP FIBFIBIncoming IP packets
Outgoing IP packets
17MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
Control-Plane to Data-Plane MPLS / E-LSR
Data plane in a nodeData plane in a node
IP Routing ProtocolIP Routing Protocol
IP Routing TableIP Routing Table
MPLS LIBMPLS LIB
Co n
tr ol p
l an e
i n a
nod
eC
o ntr o
l pl a
n e i n
a n
ode
MPLS LFIBMPLS LFIB
E-LSRE-LSREdgeEdgeLabelLabel
SwitchSwitchRouterRouter
IGPIGPRouting information
exchange with other routers
(Link-state recommended)
Label Distribution Label Distribution ProtocolProtocol
Label binding exchange with other
routers
Incoming labelled packets
Outgoing IP packets
Outgoing labelled packets
Incoming IP packets IP IP FIBFIB
18MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
Control-Plane to Data-Plane MPLS / LSR
Data plane in a nodeData plane in a node
IP Routing ProtocolIP Routing Protocol
IP Routing TableIP Routing TableC
o ntr o
l pl a
n e i n
a n
ode
Co n
tr ol p
l an e
i n a
nod
eLSRLSRLabelLabel
SwitchSwitchRouterRouter
Incoming labelled packets
Outgoing labelled packets
MPLS LFIBMPLS LFIB
MPLS LIBMPLS LIB
IGPIGPRouting information
exchange with other routers
(Link-state recommended)
Label Distribution Label Distribution ProtocolProtocol
Label binding exchange with other
routers
19© 2001, Cisco Systems, Inc. 19© 2001, Cisco Systems, Inc.
MPLS Packet Forwarding &
Label Switched Paths
20MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
MPLS Example:Routing Information
128.89
171.69
1
01
0
You can reach 171.69 through me
You can reach 128.89 and 171.69 through me
Routing Updates (OSPF, EIGRP, …)
You can reach 128.89 through me
Address Address PrefixPrefix
128.89128.89
171.69171.69
......
OutOutI’faceI’face
00
11
......
Address Address PrefixPrefix
128.89128.89
171.69171.69
......
OutOutI’faceI’face
11
11
......
Address Address PrefixPrefix
128.89128.89
......
OutOutI’faceI’face
00
......
21MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
MPLS Example:Assigning Labels
1
01
0
Use label 7 for 171.69
Use label 4 for 128.89 andUse label 5 for 171.69
Label Distribution
Use label 9 for 128.89
128.89
171.69
In In LblLbl
Address Address PrefixPrefix
128.89128.89
171.69171.69
......
OutOutI’faceI’face
00
11
......
Out Out LblLbl
In In LblLbl
Address Address PrefixPrefix
128.89128.89
171.69171.69
......
OutOutI’faceI’face
11
11
......
Out Out LblLbl
In In LblLbl
Address Address PrefixPrefix
128.89128.89
......
OutOutI’faceI’face
00
......
Out Out LblLbl
--
--
44
55
44
55
99
77
99 --
22MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
MPLS Example:Forwarding Packets
128.89
171.69
1
01
128.89.25.4 Data4128.89.25.4 Data
128.89.25.4 Data
128.89.25.4 Data9
0
Label Switch Forwards Based on Label
In In LblLbl
Address Address PrefixPrefix
128.89128.89
171.69171.69
......
OutOutI’faceI’face
00
11
......
Out Out LblLbl
In In LblLbl
Address Address PrefixPrefix
171.69171.69
......
OutOutI’faceI’face
11
11
......
Out Out LblLbl
In In LblLbl
Address Address PrefixPrefix
128.89128.89
......
OutOutI’faceI’face
00
......
--
--
44
55 55 77
--4 9128.89
Out Out LblLbl
99
23MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
Label Encapsulation
• Label header is equal to 4 octets– Label value is 20 bits– Experimental is 3 bits– S (bottom of stack) is 1 bit– TTL (Time to live) is 8 bits
0 1 2 30 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
Label | CoS|S| TTL
24MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
Label Encapsulation
ATM label switching
Packet-over-SONET/SDH
Ethernet: similar
Frame Relay PVCs: similar
Label over ATM PVCs
PPP Header LabelLabel Layer 3 Header Data
Ethernet Hdr LabelLabel Layer 3 Header Data
Frame Rly Hdr LabelLabel Layer 3 Header Data
ATM Header LabelLabel Layer 3 Header Data
ATM Header Data(subsequent cells)
GFC VPI VCI
LabelLabel
PTI CLP HEC Layer 3 Header Data
GFC VPI VCI PTI CLP HEC Data(subsequent cells)
LabelLabel
LabelLabel
25MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
The Label StackMPLS is recursive
171.68.10/24
Rtr-A
Next-HopNext-Hop
In In LabLab55
......
Address Address PrefixPrefix
171.68.10171.68.10
......
OutOutI/FI/F11
......
Out Out LabLab77
......
In In I/FI/F00
......
IP packetD=171.68.10.12
Label = 5
Label = 21
IP packetD=171.68.10.12
Label = 7
Label = 21
• Rtr-A forwards the labeled packet based on the label at the top of the label stack
26MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
Forwarding Equivalent Class
• IP Packets are classified into FECsFECs
Forwarding Equivalent ClassForwarding Equivalent Classgroup of packets forwarded in the same manner, over the same path, with the same forwarding treatment
determined (by default) through the output of the IGP (or static routing)
each FEC corresponds to an IP destination prefixdestination-based unicast routing (default)could be QOS, all BGP prefixes reachable via a particular exit point etc...
27MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
Label Switch Path (LSP)
• FEC is determined in LSR-ingress• LSR-ingress to LSR-egress path is the same for packets of the same
FEC• LSPs are derived from IGP routing information
• LSPs may diverge from IGP shortest pathLSP tunnels (explicit routing) with Traffic
Engineering
LSP follows IGP shortest path
IGP domain with a label distribution protocol
LSP diverges from IGP shortest path
IGP domain with a label distribution protocol
28MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
Frame-mode MPLSLabel Assignment
& Distribution
28© 2000, Cisco Systems, Inc.
29MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
• Each LSR assigns a local label for each FEC
label to IP prefix mapping held within the LIB (Label Information Base)
label has local significance
Frame-mode Label Assignment
London# show tag-switching tdp bindings 197.26.15.0 tib entry: 197.26.15.0/24, rev 7
local binding: tag: 30remote binding: tsr: 172.16.1.1:0, tag: 33remote binding: tsr: 172.16.1.2:0, tag: 35remote binding: tsr: 172.16.1.3:0, tag: 23remote binding: tsr: 172.16.2.1:0, tag: 59remote binding: tsr: 172.16.3.1:0, tag: 28
30MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
• Frame-mode LSRs use independent controlindependent control label assignment
as soon as a FEC appears within the IP routing table, a label is assigned and held within the LIB
LSR may label forward packets to a next-hop that does not yet have label information for the FEC
labels are not assigned to BGP routeslabels are not assigned to BGP routes
Frame-mode Label Assignment
31MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
Frame-mode Label Distribution
• Labels are exchanged between adjacent LSRs and a binding is agreed
binding will be downstream to upstream in respect of traffic flow
• Applications may require non-adjacent neighbours
Traffic EngineeringVirtual Private NetworksLDP/TDP Directed Peers
32MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
London London Brussels Brussels Paris Paris 197.26.15.0/24
Downstream/Upstream Neighbours
146.15.27.0/24
• Paris router is downstream neighbour of Brussels for FEC 197.26.15.0/24
• London is downstream neighbour of Brussels for FEC 146.15.27.0/24
34MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
Label Distribution Protocols
• Cisco IOS implements two label binding protocols for the purpose of destination-based unicast routing
TDPTDP (Tag Distribution Protocol)proprietary protocol - TCP port 711
LDPLDP (Label Distribution Protocol)IETF standards based protocol - TCP port 646
• Both protocols are functionally equivalent and can be used concurrently
35MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
London London Brussels Brussels Paris Paris 197.26.15.0/24
In Label FEC Out Label
- 197.26.15.0/24 28
In Label FEC Out Label
28 197.26.15.0/24 41
In Label FEC Out Label
41 197.26.15.0/24 -
Use label 28 for destination 197.26.15.0/24
Use label 41 for destination 197.26.15.0/24
Frame-mode Label Distribution
36MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
Label Retention
• Frame-mode LSR uses liberalliberal retention modeLSR keeps labels from neighbours that are not the best next-hop for the FECrequires more memory and label space
problem for ATM-LSR as label is a VC
improves convergence if layer-3 routing information changes, next-hop label forwarding information is already available
37MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
P-1P-2
Liberal Label Retention
LIB contains mappings from ALL neighbours
P-3
Use label 41 for destination 197.26.15.1/32 Use label 21 for destination
197.26.15.1/32
Use label 23 for destination 197.26.15.1/32
Use label 25 for destination 197.26.15.1/32
P-4
P-5
Use label 21 for destination 197.26.15.1/32
In Label FEC Out Label
24 197.26.15.1/32 23
local binding: tag: 24 remote binding: tsr: 172.16.1.1:0, tag: 23 remote binding: tsr: 172.16.1.2:0, tag: 41
38MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
Penultimate Hop Popping
• Frame-mode LSR may use Penultimate Hop Popping procedures during label forwarding
label at top of stack is removed (popped) by the upstream neighbour of the egress-LSR
requested by egress-LSR using TDP/LDPuses implicit-null label
one lookup saved at egress-LSR
39MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
Penultimate Hop Popping
London London Brussels Brussels Paris Paris
197.26.15.1/32
In Label FEC Out Label
- 197.26.15.1/32 28
In Label FEC Out Label
28 197.26.15.1/32 POP
In Label FEC Out Label
- 197.26.15.1/32 -
Use label 28 for destination 197.26.15.1/32
Use label implicit-null for destination 197.26.15.1/32
Paris# show tag-switching tdp binding 197.26.15.1 tib entry: 197.26.15.1/32, rev 10
local binding: tag: imp-null(1)remote binding: tsr: 172.16.3.1:0, tag: 28
Brussels# show tag-switching tdp binding 197.26.15.1 tib entry: 197.26.15.1/32, rev 10
local binding: tag: 28 remote binding: tsr: 172.16.3.2:0, tag: imp-null(1)
Brussels# show tag-switching forwarding Local Outgoing Prefix Bytes tag Outgoing Next Hop tag tag or VC or Tunnel Id switched interface 28 Pop tag 197.26.15.1/32 0 Se0/0/2 point2point
40MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
Cell-mode MPLSLabel Assignment
& Distribution
40© 2000, Cisco Systems, Inc.
41MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
Cell-Mode MPLS
• ATM switches cannot perform MPLS label or IP lookup
Packets exchanged as cells at layer-2VPI/VCI pair used as label
• ATM switches cannot directly exchange IP traffic
VC required for MPLS data planeControl VC used for MPLS control plane
42MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
Label Switch Router
IP Routing Protocols
IP Routing Table
MPLS Signalling Protocol
Label Forwarding Table
Con
trol P
lan e
Data Plane
Label Switch Router
IP Routing Protocols
IP Routing Table
MPLS Signalling Protocol
Label Forwarding Table
Con
trol P
lan e
Data Plane
Routing Information Exchange
Label Binding Exchange
Labelled Packets
IP & MPLS AdjacenciesControl VC
43MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
MPLS Control VC
ATM Edge LSR ATM Edge LSR
MPLS Control Plane MPLS Control Plane
ATM LSR ATM LSR
MPLS Control Plane MPLS Control Plane
ATM Data Plane ATM Data Plane
Switching Matrix Switching Matrix
ATM Control VC (0/32) - aal5snap
44MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
55
8 8
In In TagTag
240/5240/5
240/8240/8
......
Address Address PrefixPrefix
128.89128.89
128.89128.89
......
OutOutI/FI/F
00
00
......
Out Out TagTag
240/3240/3
240/3240/3
......
In In I/FI/F
11
22
......
2
5
8 33 33 33Packet
Cells
128.89
?
1 0
Packet 5
8
5 5 5
38
38 8 8 3 3 3 3
Cell-mode Label Distribution
Unsolicited Downstream label distribution breaks ATM !
(because use of same label for same FEC)
45MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
55
8 8
In In TagTag
240/5240/5
240/8240/8
......
Address Address PrefixPrefix
128.89128.89
128.89128.89
......
OutOutI/FI/F
00
00
......
Out Out TagTag
240/3240/3
240/7240/7
......
In In I/FI/F
11
22
......
2
5
8 73 73 73Packet
Cells
128.89
Now I am happy :)
1 0
Packet 5
8
5 5 5
78
7
8 8 8 3 3 7 3
Cell Flow with Multiple Labels
• Cell-mode uses Downstream on Demand label distribution with Ordered label allocation
unique label mapping for each upstream neighbour
multiple labels for the same FEC from the same next-hop neighbour
46MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
Cell-mode Label Distribution
London London POP routerPOP router
Paris Paris Peering PointPeering Point
Step #1: Label request for 146.27.15.0/24 sent to next-hop neighbour
146.27.15.0/24
Step #2: Paris allocates label and responds with
label mappingStep #3: Label mapping is propagated back to the source and labels are assigned by intermediate ATM LSRs
RQ for 146.27.15.0/24
RQ for 146.27.15.0/24
RQ for 146.27.15.0/24
146.27.15.0/24 = 1/241
146.27.15.0/24 = 1/239
146.27.15.0/24 = 1/244
47MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
Cell-mode Label Retention
• Cell-mode uses Conservative label retention mode
keep only labels that are relevant to forwarding
achieved by requesting label mapping ONLY from next-hop downstream neighbour
146.27.52.0/24
Label request to next-hop neighbour
onlyTwo paths available to 146.27.52.0/24
48MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
VC Merge
• Further technique to reduce label space is vc-merge
55
8 8
In In TagTag
240/5240/5
240/8240/8
......
Address Address PrefixPrefix
128.89128.89
128.89128.89
......
OutOutI/FI/F
00
00
......
Out Out TagTag
240/3240/3
240/3240/3
......
In In I/FI/F
11
22
......
5
8Packet
Cells
128.89
ATM LSR transmits cells in sequence so that the downstream LSR is able to correctlyreassemble the cells into packets
1
Packet 5
8
5 5 5
8 8 8 8 3 3 33 3 3 333
49© 2001, Cisco Systems, Inc. 49© 2000, Cisco Systems, Inc.
Configuring MPLS
50MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
Configure MPLS
• Global: tag-switchingtag-switching ipip is by default
• On all interfaces in the backbone : tag-switching iptag-switching ip (or) mpls ipmpls ip
• Label distribution :– TDP– LDP
• 12.0(10)ST• 12.1(1)T
51MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
Debug
• sh tag tdp discov -> Broadcast Discovery neighbors protocol
• sh tag tdp nei -> TDP (TCP session 711)
• sh tag tdp bind-> Full label exchange with all neighbors
• sh ip cef -> Select next-hop
• sh tag forwarding -> View selected Tag for destination
• sh ip cef IP@ det -> View all forwarding infos (& multi-labels)
• traceroute IP@ -> View LSP (path & tags & multi-tags)
• debug tag pac -> View LSR (P router) switching
52MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
LDP - Discovery
sh tag tdp discoveryLocal TDP Identifier: 10.21.2.2:0TDP Discovery Sources: Interfaces: Serial0/0: xmit/recv TDP Id: 10.1.2.2:0 Serial0/1: xmit/recv TDP Id: 10.21.4.4:0 Serial1/0: xmit/recv TDP Id: 10.21.3.3:0
53MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
Adjacency TDP / LDPsh tag tdp neighborPeer TDP Ident: 10.21.4.4:0; Local TDP Ident 10.21.2.2:0 TCP connection: 10.21.4.4.11001 - 10.21.2.2.711 State: Oper; PIEs sent/rcvd: 54/50; ; Downstream Up time: 00:37:57 TDP discovery sources: Serial0/1 Addresses bound to peer TDP Ident: 10.21.140.4 10.21.4.4 10.21.46.4 10.21.24.4
Peer TDP Ident: 10.21.3.3:0; Local TDP Ident 10.21.2.2:0 TCP connection: 10.21.3.3.11266 - 10.21.2.2.711 State: Oper; PIEs sent/rcvd: 24/25; ; Downstream Up time: 00:17:45 TDP discovery sources: Serial1/0 Addresses bound to peer TDP Ident: 10.21.130.3 10.21.3.3 10.21.13.3 10.21.35.3 10.21.23.3
54MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
View the LIB
sh tag tdp binding
tib entry: 10.21.5.5/32, rev 34 local binding: tag: 34 remote binding: tsr: 10.21.4.4:0, tag: 35 remote binding: tsr: 10.21.3.3:0, tag: 28 remote binding: tsr: 10.1.2.2:0, tag: 38
tib entry: 10.21.13.0/24, rev 16 local binding: tag: 28 remote binding: tsr: 10.21.4.4:0, tag: 31 remote binding: tsr: 10.21.3.3:0, tag: imp-null remote binding: tsr: 10.1.2.2:0, tag: imp-null
55MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
View the LFIB
3640-L21-R2#sh tag forwarding-tableLocal Outgoing Prefix Bytes tag Outgoing Next Hoptag tag or VC or Tunnel Id switched interface17 Aggregate 100.10.57.0/24[V] 021 20 10.10.4.4/32 0 Se0/1 point2point22 17 10.10.12.0/24 0 Se0/1 point2point26 Untagged 10.21.24.4/32 0 Se0/1 point2point27 Untagged 10.21.23.3/32 0 Se1/0 point2point28 Pop tag 10.21.13.0/24 0 Se0/0 point2point Pop tag 10.21.13.0/24 0 Se1/0 point2point29 Pop tag 10.21.35.0/24 0 Se1/0 point2point30 Pop tag 10.21.3.3/32 0 Se1/0 point2point32 Pop tag 10.21.4.4/32 0 Se0/1 point2point33 27 10.21.57.0/24 0 Se1/0 point2point34 28 10.21.5.5/32 0 Se1/0 point2point35 Untagged 10.21.12.1/32 0 Se0/0 point2point36 Pop tag 10.1.2.2/32 0 Se0/0 point2point
56MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
View the LFIB
L10-R5# sh tag forwarding tag 34 detailLocal Outgoing Prefix Bytes tag Outgoing Next Hoptag tag or VC or Tunnel Id switched interface 34 16 100.20.57.0/24[V] 0 Se0/1 point2point
MAC/Encaps=4/12, MTU=1496, Tag Stack{16 60} 0F008847 000100000003C000 VPN route: RED No output feature configured Per-packet load-sharing
57MPLS Arch_Oper_0701 © 2001, Cisco Systems, Inc. www.cisco.com
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