US008176201B1

(12) Ulllted States Patent

(10) Patent N0.:

Minei et a]. (54)

(75)

US 8,176,201 B1

(45) Date of Patent:

May 8, 2012

CONTROLLING THE SIGNALING OF

6,772,219 B1 *

LABEL-SWITCH” PATHS USINGA LABEL

232????‘ Eli (35882 $325‘;

8/2004 Shobatake .................. .. 709/238

338/323

MESSAGES DISTRIBUTION WHICH PROTOCOL EACIEITATE EMPLOYING THE USE

3335552 ’ ’ 55 E,, 85882 31111926731611: ' '

:1: 338/333

OF EXTERNAL PREFIXES

7,151,775 B1 * 12/2006 Renwick et a1.

370/400

7,197,033 B2 *

370/389

Inventors; Ina Minei’ Santa Clara’ CA (Us);

2006/0095499 A1 *

3/2007

Reeves et a1. .... ..

5/2006 Luciani et a1. .............. .. 709/201

Nischal Sheth, Sunnyvale, CA (US); Pedro R. Marques, Santa Clara, CA

* cited by examiner

(US); Yakov Rekhter, NeW Rochelle, NY (Us)

Primary Examiner * Bharat Barot (74) Attorney, Agent, or Firm * John C. Pokotylo; Straub &

(73) Assignee: Juniper Networks, Inc., Sunnyvale, CA (US)

Pokotylo (57)

( * ) Notice;

Label distribution protocol (LDP) signaled label-switched paths (LSPs) are supported Without requiring information about remote autonomous systems (ASs) to be injected into the local interior gateway protocol (1GP). This may be done

Subject to any disclaimer’ the term ofthis patent is extended or adjusted under 35 U_S,C, 154(b) by 2086 days,

(21) APPI- NOJ 10/702,184

by (i) decoupling a forwarding equivalency class (FEC) ele

_

(22) (51)

Flled: Int Cl

ment from the routing information, and (ii) specifying a next

NOV‘ 5’ 2003

G081? 25/173 (52)

hop on Which the FEC relies. An LDP messaging structure (e.g., an LDP type-length-value (TLV)) that includes a label,

(200601)

G06F 15/16 US‘ Cl‘

FEC information (e.g., a host address or pre?x of an egress

(200601) 709/238_ 709002 709/242_ 370/231_

""" "

(58)

ABSTRACT

’

LSR ofthe LSP) and a next hop (e.g., a host address or pre?x ofabordernode, suchas anAS borderrouter (ASBR)) may be

’ 370/389’_ 370/400’

provided. This messaging structure may be included in one or

Field of Classi?cation Search ................ .. a709/206 709/238i242 201*203 370/229i231 235*236’

more Om‘) label mapping messages’ 0’) label Withdraw mes‘ sages, and (c) label release messages. If an LDP message

370/351’i356, 3891392’ 408409” 40(L401’

including the expanded LDP messaging structure is received

See application ?le for Complete Search history'

(56)

at a node, the node may determine Whether or not to propagate the LSP using the next hop information, rather than the FEC information. If, on the other hand, the LDP message includes

References Cited

a normal LDP messaging structure, the node may determine U.S. PATENT DOCUMENTS 6,529,958 B1 * 6,584,071 B1 *

3/2003 6/2003

Whether or not to propagate the LSP as usual.

Oba et a1. .................... .. 709/238 Kodialam et a1. ........... .. 709/241

35 Claims, 11 Drawing Sheets

LABEL MESSAGE PROCESSING DECISION TO BREAK FEO

B02 RIGGER

LABEL MAPPING .

|

LABEL MAPPING MESSAGE RECEIVED

LABEL WITHDRAWAL

MESSAGE RECEIVED

I

we) 930

DECISION TO SEND A LABEL RELEASE

I

'

NO DOES (NORMAL 4 E MESSAGE CARRY THE OPTIONA RNH? BB5

YE

' OUTING TABLE CONTAI

AN ENTRY THAT MATCHES THE ADDRESS IN THE 7

924 ‘ DVERTISE FEC

YES INCLUDE RNH UNCHANGED IN '

92

MESSAGE AND SEND MESSAGE

E'TiEIIEMEEEFEFEXEIIIEEET‘FHEEIIII'I U‘: WITH WHICH ITWASADVERTISED

I

e@

YES

US. Patent

May 8, 2012

Sheet 6 0111

US 8,176,201 B1

FIGURE 8

805

& LDP ADVERTISEMENT

RECEIVED

5 SAVE INTERFACE ON

81% WHICH THE MESSAGE 5

WAS RECEIVED

815 NORMAL

LDP ADVERTISEMENT TYPE

EXTENDED

. .......................................

II

LOOK UP FEC INFORMATION

50F THE LDP ADVERTISEMENT‘

LOOK Up “NEXT Hop" PART

820

825% OF THE LDP ADVERTISEMENT

5 IN THE ROUTE INFORMATION 5

IN THE RouTE INFORMATION

\ ........................................ ..'

MATCHING ROUTE INFORMATION FOUND?

835

"""""""" __

RECEIVED?

Y

___________________ " ~~~~~~~~~ "

s45

SIGNAL

85

YES l 84A»

LSP V

860/

,\

RETURN I

IGNORE LDP ADVERTISEMENT

Q/I HANDLEII ERR:O:|R

US. Patent

May 8, 2012

Sheet 7 0111

US 8,176,201 B1

C LABEL MESSAGE PROCESSING ) DECISION TO BREAK FEC LABEL MAPPING I

I

I

LABEL WITHDRAWAL

LABEL MAPPING

DECISION To SEND A

MESSAGE RECEIVED

MEssAeEyREcElvED

LABEL RELEASE

970 930

§"'SAVE i_ THE MESSAGE INTERFACE-‘ON WAS RECEIVED WHICH ;

904

950

NO

(NORMAL)

YES

HE MESSAGE CARRY THE OPTIONA

8 FBR'DC'E'S'STE : NoRMALLYj

DOES NODE SUPPORT RNH? 916

NO

DOES - OUTING TABLE CONTAI

DROP

AN ENTRY THAT MATCHES THE

MESSAGE Q1912

ADDRESS IN THE

RNH? INFORM

914

SENDER q/

91?--- " ------------------__ Is THE ,,,,,, "DOWNSTREAM NEIGHBOR FROM'~~.___ 920

WHICH THE LABEL MAPPING WAS RECEIVED------ a _T__HE NEXT HOP TO THE ADDRESS IN THE RN_l_-l_ ------ "

2 v

------ __ACCORDING TO THE ROUT|NG_ ...... -'

DO NOT USE

__________ __

LABEL FOR

'

FORWARDING

924 NO YES

926

INCLUDE RNH UNCHANGED IN

\I\

MESSAGE AND SEND MESSAGE

_______ __

I

: REMEMBER, FOR EACH FEC, THE RNH

a

WITH WHICH IT WAS ADVERTISED A

990@ FIGURE 9A

990

US. Patent

May 8, 2012

Sheet 8 0111

US 8,176,201 B1

FIGURE 98 YES

932 ASSOCIATED WITH

INCLUDE RNH

IL AND LABEL IN 936 WWHDRAWAL MESSAGE

PROCESS 1934 NORMALLY

990

FIGURE 9C YES

952 ASSOCIATED WlTH

INCLUDE RNH

95gb AND LABELIN RELEASE MESSAGE

R

E

P 09 83 V54 NORMALLY

990

US. Patent

May 8, 2012

FIGURE 9D

Sheet 9 0111

US 8,176,201 B1

970 a

972 LABEL WITHDRAWAL MESSAGE CONTAIN

WITHDRAWAL MESSAGE ASSOCIATED WITH ANY RN H AT NODE?

97v

NORMAL

IS FEC INDICATED IN WITHDRAWAL MESSAGE ASSOCIATED AT NODE WITH A NEXT HOP MATCHING HAT INDICATED IN TH MESSAGE?

PROCESSING

v

DROP

DROP

MESSAGE W8

981/‘ MESSAGE

5'miiii??gé?b'é'é'6F"' -

5

“MISSINGRNH”

5 98°

---------------------------------- --

r ______________________________ ____

98\6/~" 5

NOTIFYSENDEROF 5

"INCOMPATIBLE RNH”

5

US. Patent

May 8,2012

Sheet 10 01 11

US 8,176,201 B1

co p Q P

mOw E

omow

MorDOE om

‘l/vmor

H

m0O