© 2000, Cisco Systems, Inc. 3-1 Chapter 3 Label Distribution Protocol

© 2000, Cisco Systems, Inc. 3-1

Chapter 3Chapter 3

Label Distribution Protocol

Label Distribution Protocol

© 2000, Cisco Systems, Inc. www.cisco.com CMPLS 1.0—3-2

ObjectivesObjectives

Upon completion of this chapter, you will be able to perform the following tasks:• Explain the mechanics of Label Distribution Protocol

• Demonstrate how labels are assigned, distributed, ..encoded and discovered

• Identify Show and Config commands used in Label ..Distribution Protocol

• Identify the Debug commands used in Label Distribution ..Protocol

© 2000, Cisco Systems, Inc. www.cisco.com 3-3

Label Distribution Protocol OverviewLabel Distribution Protocol Overview


Label Switching Control Plane

<t R1, P> <t R2,P>

FIB

LFIB

UnLabelged Pkt

Labelged Pkt

UnLabelged Pkt

Labelged Pkt

UnLabelged Pkt

Labelged Pkt

R1 R2


Label Control Plane Populates LIB and LFIB

Label Information Base (LIB)

Label Forwarding Information Base (LFIB)

Label Distribution

In Label Out Label Interface

tR1 tR2 i3

Destination In Label (Peer, Out Label),…

D tR1 (R2:0, tR2), R3:0, tR3), (R4:0, tR4)


Label Distribution Terminology

P dest D

Label for D

UpstreamPlatform

DownstreamPlatform

P dest D

Label for D

UpstreamPlatform

DownstreamPlatform

Ru Rd

Ru Rd


Label Assignment

Assignment of incoming (local) Labels:–Per Interface: For interfaces that use

interface resources for Labels

–Per Platform: For interfaces that share the same Labels


Downstream Label Distribution Variants

Downstream

Downstream on Demand

Label for D

P Destination D

UpstreamLSR

DownstreamLSR

Ru Rd


Label Distribution Possibilities

• Dynamic Label Switching

–Enhance routing protocol to carry Labels

–Use protocol designed to distribute Labels

• For TSP Tunnels

–Enhance RSVP to carry Labels

–Use protocol designed to distribute Labels


Label Distribution Protocol (LDP)

• Runs in parallel with routing protocols

• Distributes <Label, prefix> bindings

• Incremental updates over TCP

• Other Label distribution mechanisms can run in parallel with it


LDP Identifier

• Identifies Label space

• 6 bytes

• Cisco convention

–a.b.c.d:n

a b c d n

Router ID Label Space ID


LDP Sessions and Label Spaces

• LDP sessions support Label exchange between LSRs

• Design choice is to use one Label space per LDP session rather than many Label spaces per LDP session


Link Topology and LDP Sessions

L2 L4

L1 L3

Topology:

LDPSessions:

L1

L2L3

R1 R2R1

R2

R4

R3

Session for L1 Session for L3

Session for L2 Session for L4

R1

R2

R4

R3

Session for L1, L2, L3

R1 R2


Link Topology and LDP Sessions (cont.)

Topology:

LDPSessions:

L2(ATM)

L1(ATM)

Session for L2

Session for L1

R1 R2

R1 R2

L1

L2(ATM)

L3

Session for L1, L3

Session for L2

R1 R2

R1 R2


LDP Transport

Uses TCP for reliable transport

Well-known contact port (711)

Design Choice:

One LDP session per TCP connection


LDP Discovery

LSRs learn Label neighbors via LDP discovery

?

? ?

Hello, T1:0 Hello, T1:1

Hello, T1:0

? ?atm atm atm

Hello, T2:3

Hello, T3:0Hello, T4:0

? ?

? ? ?

T4:0T3:0

T1 T2:3T1T1T1


LDP Sessions and Keep Alives

LDP monitors health and necessity of sessions

• Keep Alive PIEs monitor integrity of transport connection

• Discovery Hello PDUs signal peer willingness to Label switch on link


LDP Identifiers and Next Hop Addresses

LIB stores Labels with peer LDP Identifiers

Routing maintains next-hop IP addresses

Dest In Label (Peer, Out Label),…

D tR1 (R2:0, t R2), (R3:0, tR3 ), (R4:0, tR4)

Dest Next Hop Interface Pctl Metric

D a.b.c.d i3 OSPF 100

LIB Routing Table


LDP Identifiers and Next Hop Addresses (cont.)

• LFIB requests Label assigned by next-hop for destination

• LIB maps next-hop address to peer LDP identifier to retrieve Label

LSRs:

–Advertise interface addresses via LDP

–Build peer LDP identifer <-> Address Map from learned addresses


Label Distribution Protocol MechanicsLabel Distribution

Protocol Mechanics



Label Assignment

Assignment of incoming (local) Labels:• Per Interface: For interfaces that use

interface resources for Labels

• Per Platform: For interfaces that share the same Labels


Label Distribution Protocol (LDP)

• Runs in parallel with routing protocols

• Distributes <Label, prefix> bindings


• Other Label distribution mechanisms can run in parallel with it


LDP Identifier

• Identifies Label space

• 6 bytes

• Cisco convention

–a.b.c.d:n

a b c d n

Router ID Label Space ID


LDP Sessions and Label Spaces

• LDP sessions support Label exchange between LSRs

• Design choice is to use one Label space per LDP session rather than many Label spaces per LDP session


Link Topology and LDP Sessions

Topology:

LDPSessions:

L2(ATM)

L1(ATM)

Session for L2

Session for L1

R1 R2

R1 R2

L1

L2(ATM)

L3

Session for L1, L3

Session for L2

R1 R2

R1 R2


LDP EncodingLDP Encoding

LDP TCP connection carries protocol data units (PDUs)

PDU carries one or more protocol information elements (PIEs)

Type-Length-Value (TLV) encoding provides extensibility

1 2 30

PIE LenPIE Len

PIE DataPIE Type PIE Len

1 2 3 4 5 6 7 8 9 10 110

PDU Len

Ptcl Ver PDU Len Res PIE 1 PIE 2 PIE nLDP ID

1 2 30

TLV LenTLV Len

ValueType Len


LDP Protocol Information Elements (PIEs)

LDP PIEs include:• Open

• Bind, Request Bind, Withdraw Bind

• Address, Withdraw Address

• Keep Alive


LDP Discovery

LSRs learn Label neighbors via LDP discovery

?

? ?

Hello, T1:0 Hello, T1:1

Hello, T1:0

? ?atm atm atm

Hello, T2:3

Hello, T3:0Hello, T4:0

? ?

? ? ?

T4:0T3:0

T1 T2:3T1T1T1

(Corrected Slide)


Discovery Triggers LDP Session Establishment

• Receive Hello T2:0 on link

• Open LDP TCP connection to T2

• Negotiate session parameters via Open PIEs

T1:0 T2:0

Hello, T2:0

Hello, T1:0

Link L


LDP Sessions and Adjacencies

LDP session =1 transport adjacency + 1 or more link adjacencies

LDP Session with T2- 1 transport adjacency- 1 link adjacency

LDP session with T2- 1 transport adjacency- 3 link adjacencies

T1T1 T2T2 T1T1Link L

Link L1

Link L2

Link L3

T2


LDP Sessions and Keep Alives

LDP monitors health and necessity of sessions

• Transport adjacency. Keep Alive PIEs monitor integrity of transport connection

• Link adjacency. Discovery Hello PDUs signal peer willingness to Label switch on link


LDP Sessions Between Non-Directly Connected LSRs

BGP EgressRouter

Normally Routed Path

Traffic Engineering Route

R9R8R7 R6 R5

R4R3R2

R1


LDP Directed Hellos

• Extend LDP Discovery to non-directly connected LSRs

• Differ from normal Hello’s

–Sent to specific address

– Initiator solicits Directed Hello’s from target


Populating the LFIB with Labels

• LIB holds

– Labels locally assigned

– Labels learned from LDP peers

• LFIB updates triggered by

– Routing changes

– Label advertisements from peers

LFIBLFIBLIBLIBLDPLDP

LDP Bind PIE (D, Label)

add_Label(LDP_id, D, Label)find_route_Labels(D, next_hop)

route_Label_change (D, next_hop, inLabel, outLabel)

Routing Change (D, next_hop)

Routing


Label Distribution Mechanics: Downstream Method

• Distributes per-platform Label space

• Supporting data structures:

–LIB

–Label Distribution Peer Database

• Periodic scan of data structures finds peers that need Label advertisements


D6seq 3t2

D3seq 4t4

D1seq 8t6

D2seq 11t10

D4seq 17t13

Label Distribution Mechanics: Downstream Method Example

Start ofupdate

list

End ofupdate

list

radixtree

Label DistributionPeer Database

LIB

D5seq 21t16

R1:0seq 8R1:0seq 8

R2:0seq 3

R3:0seq 21R3:0seq 21


Label Distribution Mechanics: Downstream on Demand

• Distributes per-interface Label space (e.g. Label Controlled ATM)

• Upstream LSR requests Label for specific destination from downstream LSR

• Builds Label VC from Head End platform to Tail End platform


Label Distribution Mechanics Downstream on Demand Example

HeadEnd

TailEndLabel VC

. . . D

Request Bind (D) Request Bind (D) Request Bind (D)

S1 S2

S1 S2

Bind (D, Label )S1

Bind (D, Label )S2

Bind (D, Label )R2

R2

R2

R1

R1


LDP Show & Config Commands

LDP Show & Config Commands



LDP Show CommandsExample Network

ether1/1/1

ether1/1/2

ether4/0/1

ether4/0/1

atm0/0/3 atm0/0/3atm1/0 atm0/0/1 atm3/0atm0/0/1

atm0/0/2atm0/0 atm0/0/2 atm0/0/0 atm0/0atm0/0/0

S2 S7R9 R8


Show LDP Parameters

Labelsw-r9#show Label-switching LDP parametersProtocol version: 1Downstream Label pool: min Label: 10; max_Label: 10000; reserved

Labels:16Session hold time: 30 sec; keep alive interval: 10 secDiscovery hello: holdtime: 20 sec; interval: 4 secDiscovery directed hello: holdtime: 15 sec; interval: 5 sec

Labelsw-r9#


Show LDP Discovery Information

Labelsw-r8#show Label-switching LDP discoveryLocal LDP Identifier:

210.8.0.8:0LDP Discovery Sources:

Interfaces:ATM0/0.1: xmit/recv

LDP Id: 203.0.7.7:2Ethernet1/1/1: xmit/recv

LDP Id: 210.9.0.9:0Ethernet1/1/2: xmit/recv

LDP Id: 210.9.0.9:0ATM3/0.1: xmit/recv

LDP Id: 203.0.7.7:1Labelsw-r8#


LDP Neighbor Information: LS1010 Example

Labelsw1010-7#show Label-switching LDP neighborPeer LDP Ident: 210.8.0.8:2; Local LDP Ident 203.0.7.7:1

TCP connection: 210.8.0.8.11004 - 203.0.7.7.711State: Oper; PIEs sent/rcvd: 20852/20863; Downstream on demandUp time: 1d01hLDP discovery sources:

ATM0/0/0Peer LDP Ident: 210.8.0.8:1; Local LDP Ident 203.0.7.7:2






ATM0/0/3Labelsw1010-7#


LDP Label Binding Information: Router

Labelsw-r8#show Label-switching LDP neighborPeerLDP Ident: 203.0.7.7:1; Local LDP Ident 210.8.0.8:2


ATM3/0.1PeerLDP Ident: 203.0.7.7:2; Local LDP Ident 210.8.0.8:1


ATM0/0.1PeerLDP Ident: 210.9.0.9:0; Local LDP Ident 210.8.0.8:0

TCP connection: 210.9.0.9.11125 - 210.8.0.8.711State: Oper; PIEs sent/rcvd: 20831/20849; DownstreamUp time: 1d01hLDP discovery sources:

Ethernet1/1/2Ethernet1/1/1

Addresses bound to peer LDP Ident:10.99.0.9 172.27.32.29 10.105.0.9 10.106.0.9 10.111.0.9 10.205.0.9 210.9.0.9

Labelsw-r8#


LDP Label Binding Information: Router (cont.)

Labelsw-r8#show Label-switching LDP bindingMatching entries:

LIB entry: 10.11.0.11/32, rev 25remote binding: LSR: 210.9.0.9:0, Label: 26



LIB entry: 10.102.0.0/16, rev 7local binding: Label: 26remote binding: LSR: 210.9.0.9:0, Label: 29

LIB entry: 10.105.0.0/16, rev 6local binding: Label: imp-null(1)remote binding: LSR: 210.9.0.9:0, Label: imp-null(1)

...Labelsw-r8#


LDP Session Hold TimeLabelsw-r8(config)#Label-switching LDP holdtime ? <1-2147483647> Holdtime in seconds

Labelsw-r8(config)#

Label Range for Label SwitchingLabelsw-r8(config)#Label-switching Label-range downstream<min

Label> <max Label> <#resv Label>Labelsw-r8(config)#

Label Switching Configuration


LDP Discovery

Labelsw-r8(config)#Label-switching LDP discovery ?directed-hello LDP discovery Directed Hellohello LDP discovery Hello

Labelsw-r8(config)#

Labelsw-r8(config)#Label-switching LDP discovery hello ?holdtime LDP discovery Hello holdtimeinterval LDP discovery Hello interval

Labelsw-r8(config)#

Labelsw-r8(config)#Label-switching LDP discovery directed-hello ?holdtime LDP discovery Directed Hello holdtimeinterval LDP discovery Directed Hello interval

Labelsw-r8(config)


LDP Debug CommandsLDP Debug Commands



Summary of LDP Debug Commands

router#debug Label LDP ?advertisements LDP Label and address advertisementsbindings Label bindings and other Label Information Base (LIB) changespeer LDP peerpies LDP Protocol Information Elementssession LDP sessionLabelcon Label control processtransport LDP transport and discovery


router#debug Label LDP advertisements

Labelcon:adj 210.9.0.9:0 (pp 0x60D428E8): advertise 10.120.0.8Labelcon:adj 210.9.0.9:0 (pp 0x60D428E8): advertise 172.27.32.28Labelcon:adj 210.9.0.9:0 (pp 0x60D428E8): advertise 10.105.0.8Labelcon:adj 210.9.0.9:0 (pp 0x60D428E8): advertise 10.106.0.8Labelcon:adj 210.9.0.9:0 (pp 0x60D428E8): advertise 10.205.0.8Labelcon:adj 210.9.0.9:0 (pp 0x60D428E8): advertise 210.8.0.8Labelcon:adj 210.9.0.9:0 (pp 0x60D428E8): advertise 10.106.0.0/16,Label 1(#7)Labelcon:adj 210.9.0.9:0 (pp 0x60D428E8): advertise 10.105.0.0/16,Label 1(#8) . . .Labelcon:adj 210.9.0.9:0 (pp 0x60D428E8):advertise 10.111.0.0/16,Label 28(#18)Labelcon:adj 210.9.0.9:0 (pp 0x60D428E8):advertise 203.0.2.2/32, Label 29(#20)


router#debug Label LDP bindings

Labelcon: libent(10.7.0.7/32): created; find route Labels requestLabelcon: libent(10.7.0.7/32): lcl Label 26 (#2) assignedLabelcon: libent(10.11.0.11/32): created; find route Labels requestLabelcon: libent(10.11.0.11/32): lcl Label 27 (#4) assignedLabelcon: libent(10.99.0.77/32): created; find route Labels requestLabelcon: libent(10.99.0.77/32): lcl Label 28 (#6) assignedLabelcon: 210.9.0.9:0: 10.99.0.9 added to addr<->LDP ident mapLabelcon: 210.9.0.9:0: 172.27.32.29 added to addr<->LDP ident mapLabelcon: libent(10.99.0.77/32): rem Label 28 from 210.9.0.9:0 added...Labelcon: libent(10.7.0.7/32): deletedLabelcon: libent(10.11.0.11/32): deleted


router#deb Label LDP peer state-machine

Labelcon: start LDP TCP timers for 200.26.0.4:1 (pp 0x60F28FF8)Labelcon: adj 200.26.0.4:1-1 (pp 0x60F28FF8): Event unsol open unsol op pdg -> estabLabelcon: adj 210.9.0.9:0 (pp 0x60F1DEA4): Event down estab -> dstroyLabelcon: adj 210.9.0.9:0 (pp 0x60F1DEA4): Event cleanup done dstroy -> non-exLabelcon: adj 200.26.0.4:1 (pp 0x60F28FF8): Event down estab -> dstroyLabelcon: adj 200.26.0.4:1 (pp 0x60F28FF8): Event cleanup done dstroy -> non-exLabelcon: start LDP TCP timers for 200.26.0.4:1 (pp 0x60EBB9AC)Labelcon: adj 200.26.0.4:1-1 (pp 0x60EBB9AC): Event unsol open unsol op pdg -> estab


router#debug Label LDP pies received [all]

LDP: Rcvd open PIE from 171.69.204.234 (pp 0x0)LDP: Rcvd keep_alive PIE from 171.69.204.234:0 (pp 0x0)LDP: Rcvd bind PIE from 171.69.204.234:0 (pp 0x60ECC094)LDP: Rcvd bind PIE from 171.69.204.234:0 (pp 0x60ECC094)LDP: Rcvd notification PIE from 171.69.204.234:0 (pp 0x60ECC094)LDP: Rcvd address PIE from 171.69.204.234:0 (pp 0x60ECC094)


router#debug Label LDP pies sent [all]

LDP: Queued open PIE to 171.69.204.234 (pp 0x0)LDP: Sent open PIE to 171.69.204.234 (pp 0x0)LDP: Queued keep_alive PIE to 171.69.204.234:0 (pp 0x0)LDP: Sent keep_alive PIE to 171.69.204.234:0 (pp 0x0)LDP: Queued address PIE to 171.69.204.234:0 (pp 0x60ECC094)LDP: Sent address PIE to 171.69.204.234:0 (pp 0x60ECC094)LDP: Queued bind PIE to 171.69.204.234:0 (pp 0x60ECC094)LDP: Queued bind PIE to 171.69.204.234:0 (pp 0x60ECC094)LDP: Queued bind PIE to 171.69.204.234:0 (pp 0x60ECC094)LDP: Queued bind PIE to 171.69.204.234:0 (pp 0x60ECC094)LDP: Sent bind PIE to 171.69.204.234:0 (pp 0x60ECC094)LDP: Sent bind PIE to 171.69.204.234:0 (pp 0x60ECC094)LDP: Sent bind PIE to 171.69.204.234:0 (pp 0x60ECC094)LDP: Sent bind PIE to 171.69.204.234:0 (pp 0x60ECC094)


router#debug Label LDP session io [all]

LDP: Rcvd open PIE from 171.69.204.234 (pp 0x0)--LDP open PIE: PDU hdr: LDP Id: 171.69.204.234:0; PIE Contents: 0x00 0x01 0x00 0x10 0xAB 0x45 0xCC 0xEA 0x00 0x00 0x00 0x00 0x01 0x00 0x00 0x04 0x01 0x00 0x00 0x0F LDP: Sent keep_alive PIE to 171.69.204.234:0 (pp 0x0)--LDP keep_alive PIE: PDU hdr: LDP Id: 172.27.32.28:0; PIE Contents: 0x00 0x01 0x00 0x0C 0xAC 0x1B 0x20 0x1C 0x00 0x00 0x00 0x00 0x05 0x00 0x00 0x00 LDP: Rcvd keep_alive PIE from 171.69.204.234:0 (pp 0x0)--LDP keep_alive PIE: PDU hdr: LDP Id: 171.69.204.234:0; PIE Contents: 0x00 0x01 0x00 0x0C 0xAB 0x45 0xCC 0xEA 0x00 0x00 0x00 0x00 0x05 0x00 0x00 0x00 LDP: Sent address PIE to 171.69.204.234:0 (pp 0x60D6D884)--LDP address PIE: PDU hdr: LDP Id: 172.27.32.28:0; PIE Contents: 0x00 0x01 0x00 0x30 0xAC 0x1B 0x20 0x1C 0x00 0x00 0x00 0x00 0x08 0x00 0x00 0x24 0x00 0x01 0x00 0x03 0x00 0x1E 0x20 0x63 0x65 0x00 0x08 0x20 0xAC 0x1B 0x20 0x1C 0x20 0x0A 0x69 0x00 0x08 0x20 0x0A 0x5C 0x00 0x08 0x20 0x0A 0xCD 0x00 0x08 0x20 0xd2 0x08 0x00 0x08


router#debug Label LDP session state-machine

LDP: adj:210.9.0.9(0x60E0E034): Event: Xport opened; Non-existent -> Init pasvLDP: LDP_create_ptcl_adj: tp = 0x60E0E034, ipaddr = 210.9.0.9LDP: adj:210.9.0.9(0x60E0E034): Event: Xport opened; Init pasv -> Init pasvLDP: adj:10.105.0.9(0x60E0E034): Event: Rcv LDP Open; Init pasv -> Open rcvd pasvLDP: adj:10.105.0.9(0x60E0E034): Event: Rcv LDP KA; Open rcvd pasv -> OperLDP: adj:unknown(0x60E0E034): Event: Xport closed; Oper -> Non-existent


router#debug Label LDP transport connections

Debug output at active peer:

LDP: Opening conn; adj 0x60D3AC50, 210.9.0.9 <-> 210.8.0.8LDP: Conn is up; adj 0x60D3AC50, 210.9.0.9:11165 <-> 210.8.0.8:7110LDP: Conn closed by peer; adj 0x60D3AC50 210.9.0.9:11165 <-> 210.8.0.8:711, Ethernet4/0/1LDP: Closing conn 210.9.0.9:11165 <-> 210.8.0.8:711, adj 0x60D3AC50

Debug output at passive peer:

LDP: Incoming conn 210.8.0.8:711 <-> 210.9.0.9:11164LDP: Conn closed by peer; adj 0x60D0B8B8

210.8.0.8:711 <-> 210.9.0.9:11164, Ethernet1/1/2LDP: Closing conn 210.8.0.8:711 <-> 210.9.0.9:11164, adj 0x60D0B8B8


router#debug Label LDP transport events

LDP: LDP_set_intf_id: intf 0x60D40D50, Ethernet1/1/1, not tc-atm, intf_id 0LDP: Rcvd hello; Ethernet1/1/1, from 10.105.0.9 (210.9.0.9:0), intf_id 0, opt 0x4LDP: Hello from 10.105.0.9 (210.9.0.9:0) to 255.255.255.255, opt 0x4LDP: New adj 0x60D3852C from 10.105.0.9 (210.9.0.9:0), Ethernet1/1/1LDP: Ignore Hello Timer for Ethernet1/1/1; intf not LDP readyLDP: Send hello; Ethernet1/1/1, src/dst 10.105.0.8/255.255.255.255, inst_id 0LDP: Incoming conn 210.8.0.8:711 <-> 210.9.0.9:11166LDP: Found adj 0x60D3852C for 210.9.0.9 (Hello xport addr opt)LDP: New temporary adj 0x60D385D8 from 210.9.0.9LDP: Real adj 0x60D3852C bound to 210.9.0.9:0, replacing temp adj 0x60D385D8LDP: Adj 0x60D385D8; state set to closedLDP: Rcvd hello; Ethernet1/1/1, from 10.105.0.9 (210.9.0.9:0), intf_id 0, opt 0x4...Labelsw-r8#conf tLabelsw-r8(config)#int ether 1/1/1Labelsw-r8(config)#no Label ip...LDP: Ignore Hello from 10.105.0.9, Ethernet1/1/1; no intfLDP: Ignore Hello from 10.105.0.9, Ethernet1/1/1; no intfLDP: Ignore Hello from 10.105.0.9, Ethernet1/1/1; no intfLDP: Hold timer expired for adj 0x60D3852C, will close connLDP: Closing conn 210.8.0.8:711 <-> 210.9.0.9:11166, adj 0x60D3852CLDP: Adjacency 0x60D3852C, 10.105.0.9 timed outLDP: Adj 0x60D3852C; state set to closedLDP: Ignore Hello from 10.105.0.9, Ethernet1/1/1; no intfrouter#...


Label Distribution Protocol Summary

• LDP runs in parallel with routing protocols

• Used to distribute <Label, prefix> bindings


• Other Label distribution mechanisms can run in parallel with LDP


Summary

After completing this chapter, you should be able to perform the following tasks:• Explain the mechanics of Label Distribution Protocol

• Demonstrate how labels are assigned, distributed, encoded and discovered

• Identify Show and Config commands used in Label Distribution Protocol

• Identify the Debug commands used in Label Distribution Protocol


Review Questions

1. What are some of the features of Label Distribution Protocol?

2. In Link Adjacency, what causes an LSR to terminate a link?

3. What function do Keep-Alive PIEs perform?

4. How does the discovery process trigger an LDP session to be created?

5. How are Directed Hellos different from Normal Hellos?


Review Questions (cont.)

6. What events trigger updates to the Label Forwarding Information Base (LFIB)?

7. What command do you use to get detailed information on the number of PIEs sent and received on all LDP discovery sources?

8. What purpose do LDP configuration commands serve?

9. What debug command lists a summary of all LDP Debug commands?

Documents

© 2000, Cisco Systems, Inc. 3-1 Chapter 3 Label Distribution Protocol