BGP-TE APPLICATION LEVEL TOPOLOGY INTELLIGENCE

Transcription

1 BGP-TE APPLICATION LEVEL TOPOLOGY INTELLIGENCE Hannes Gredler 1 Copyright 2012 Juniper Networks, Inc.

2 MOTIVATION Look across the fence Fence being IGP area/level or AS boundary Gain visibility for application(s) which need complete topology data ALTO CDNI Inter-{Area, AS} TE High frequency API 2 Copyright 2012 Juniper Networks, Inc.

3 HISTORICAL INSIGHT BUILDING AN ALTO SERVER (1) Alto Client Alto Client Alto Client HTTP Alto Server Level 1 Prefix 1, 2, 3, Non-Backbone Area BGP Speaker IGP Router IGP Peering Level 1 IGP Non-Backbone Area Router BGP Speaker Prefix 11, 12, 13, BGP IGP Speaker Router IGP IGP Router Level 2 Router IGP Backbone Area Router Prefix 31, 32, 33, Level 1 Non-Backbone Area Prefix 21, 22, 23, AS1 Level 1 IGP Non-Backbone Area Router BGP Speaker ALTO server needs to know all areas topology Manually crafting of IGP peering topology is tedious and error prone!!! 3 Copyright 2012 Juniper Networks, Inc.

4 HISTORICAL INSIGHT BUILDING AN ALTO SERVER (2) External Applications need to access rpd internal data BGP Internet (SAFI 1) prefixes IGP Topology data Need to define an API (Session and IPC) PUSH or PULL model? IPC format? Would it make sense to standardize this API? ALTO Server rpd BGP Peers P2P Clients IPC: FSM, Decoder, DB Session Per Protocol: FSM, Encoder, Decoder, DB, routeresolution, IPC DB IPC DB IGP Adjacencies 4 Copyright 2012 Juniper Networks, Inc.

5 USE CASE INTER-REGION TRAFFIC ENGINEERING RSVP Loose hop expansion has practical deployment limits Vanilla RSVP has no crank-back in case it sees new information that it did not see at previous hops. (and RFC4920 has a lot of caveats) Area 51 R1 X ABR1 Main LSP SRLG 666 Area 0 R3 ABR3 Area 47 R5 S D Bypass LSP R2 ABR2 R4 ABR4 SRLG 666 R6 5 Copyright 2012 Juniper Networks, Inc.

6 STATUS IETF WORK draft-gredler-idr-ls-distribution-02 The protocol allows Topology data (links and nodes) to be shared in a protocol agnostic (no OSPFism, no IS-IS ism) form. Joint work with Cisco Call for adoption as idr-wg item (Aug 31) So far positive feedback, Usual criticism on BGP bloat Want to move further work to SDN-WG 6 Copyright 2012 Juniper Networks, Inc.

7 IMPLEMENTATION IN JUNOS Key of IETF draft is protocol agnostic representation of nodes and links Wait a bit don t we have something like this already in JUNOS??? Yes its called the Traffic engineering database (TED) => Need to transcode node/links information from/to TED into BGP hannes@r1> show ted link detail TED database: 0 ISIS nodes 3 INET nodes ID Type Age(s) LnkIn LnkOut Protocol Rtr OSPF( ) To: , Local: , Remote: Local interface index: 0, Remote interface index: 0 ID Type Age(s) LnkIn LnkOut Protocol * * *Rtr * OSPF( ) *To: *, Local: , Remote: Local interface index: 0, Remote interface index: 0 ID Type Age(s) LnkIn LnkOut Protocol * * *Net * OSPF( ) To: , Local: , Remote: Local interface index: 0, Remote interface index: 0 *To: *, Local: , Remote: Local interface index: 0, Remote interface index: 0 7 Copyright 2012 Juniper Networks, Inc.

8 TRANSCODING TE LINK INFO INTO BGP NLRI Carried in MP_REACH_NLRI path attribute MP_UNREACH_NLRI path attribute LS_ATTRIBUTES path attribute Two NLRI types Node Link Each NLRI describes a single link anchored by at least a pair of router-ids Link may be anchored by more than one pair of Router-IDs Negotiated between BGP speakers using BGP-MP Capability 8 Copyright 2012 Juniper Networks, Inc.

9 TED NLRI TYPES: NODES AND LINKS 9 Copyright 2012 Juniper Networks, Inc. 9

10 ROUTER-ID ANCHORING EXAMPLE: ISO PSEUDONODE Broadcast LAN between a pair of routers: Real" (=non pseudonode) routers have both an IPv4 Router-ID and IS-IS Node-IDs The pseudonode does not have an IPv4 Router-ID. Two unidirectional links being generated: NRLI #1for (R1, Pseudonode) encodes: local IPv4 router-id, local ISO node-id and remote ISO node-id NLRI #2 for (Pseudonode, R2) encodes: local ISO node-id, remote IPv4 router-id and remote ISO node-id. 10 Copyright 2012 Juniper Networks, Inc.

11 STATE FLOW peer BGP Import policy BGP Export policy peer bgp.traffic-engineering TED export policy TED import policy TED 11 Copyright 2012 Juniper Networks, Inc.

12 TRAFFIC ENGINEERING RIB show route table bgpte.0 bgpte.0 : 7 destinations, 7 routes (7 active, 0 holddown, 0 hidden) + = Active Route, - = Last Active, * = Both *LINK { Local { IPv4: } Remote { IPv4: } OSPF:0 }/576 *[OSPF/512] 00:16:50 Fictitious *LINK { Local { IPv4: } Remote { IPv4: } OSPF:0 }/576 *[OSPF/512] 00:16:48 Fictitious *LINK { Local { IPv4: } Remote { IPv4: } OSPF:0 }/576 *[OSPF/512] 00:16:48 Fictitious *LINK { Local { IPv4: ISO: } Remote { ISO: } ISIS-L1:0 }/576 *[BGP/170] 00:09:31, localpref 100, from AS path: I Fictitious *LINK { Local { IPv4: ISO: } Remote { ISO: } ISIS-L1:0 }/576 *[BGP/170] 00:09:31, localpref 100, from AS path: I Fictitious *LINK { Local { IPv4: ISO: } Remote { ISO: } ISIS-L2:0 }/576 *[BGP/170] 00:08:17, localpref 100, from AS path: I Fictitious 12 Copyright 2012 Juniper Networks, Inc.

13 BGP-TE SUMMARY Distribution of node and link data beyond IGP boundaries Enables Inter {Area,Domain} C-SPF signaling JUNOS Implementation available for testing in Q Please contact Nitin Bahadur in case you want to test-ride That s cool, but is there anything beyond? 13 Copyright 2012 Juniper Networks, Inc.

14 TRAFFIC ENGINEERING Copyright 2012 Juniper Networks, Inc.

15 TRAFFIC ENGINEERING 2.0 THE PROBLEM AS1 AS 1 ASBR3 R1 ASBR1 ASBR4 S AS 2 ASBR5 R2 ASBR2 ASBR6 15 Copyright 2012 Juniper Networks, Inc.

16 ADD A RSVP-TE-LSP AS1 AS 1 ASBR3 R1 ASBR1 ASBR4 S AS 2 ASBR5 RSVP-TE LSP R2 ASBR2 ASBR6 16 Copyright 2012 Juniper Networks, Inc.

17 COMMON TRAFFIC ENGINEERING PROBLEMS RSVP-TE LSPs are big Hammers Lack of egress Control Node control vs. Link control, ideally per prefix Low frequency (sensor) update TE stats available through SNMP/CLI/File uploads Low frequency (actor) update Human interaction Machine based: Through Config Transactional Interface 17 Copyright 2012 Juniper Networks, Inc.

18 1 ST ADD A HIGH-FREQUENCY MP2MP SIGNALING API AS1 AS 1 ASBR3 R1 ASBR1 ASBR4 S AS 2 ASBR5 R2 ASBR2 ASBR6 RR TE-APP 18 Copyright 2012 Juniper Networks, Inc.

19 2 ND ADD FURTHER NLRI TYPES TO BGP-TE Traffic statistics Interface & TE LSPs TE LSP status report Discover MPLS LSPs Targeted TE LSP setup (P2P, Protection, P2MP) IP Prefix to TE Tunnel mapping (=granular control) Egress Nexthop control Add indirection-layer through BGP-TE 19 Copyright 2012 Juniper Networks, Inc.

20 PUTTING IT ALL TOGETHER. MAP 5%, LSP #1, BGP-NH {ASBR3} MAP 17%, LSP #1, BGP-NH {ASBR4} MAP 35%, LSP #1, BGP-NH {ASBR5} MAP 43%, LSP #1, BGP-NH {ASBR6} RSVP-TE LSP #1 S R1 RSVP-TE LSP #2 RR R2 AS1 TE-APP ASBR1 ASBR2 AS 1 ASBR3 ASBR4 AS 2 ASBR5 ASBR6 Use Labeled-BGP to discover remote routers Preserve BGP NH of Internet routes Program WAN links to send high frequency traffic stats Setup LSP Transport mesh (=more than one) for desired core-link loading Send Prefix / Tunnel Map message to control binding of Prefixes to LSPs / and BGP NHs 20 Copyright 2012 Juniper Networks, Inc.

21 SUMMARY & FUTURE BGP-TE is is foundation for software-defined networking in JUNOS Topology discovery TE LSP discovery and setup IP Prefix to TE Tunnel mapping High-frequency API In IETF speak we call this BGP-TE southbound API Internet-draft on BGP-TE Southbound to be published after SDN-wg constitution, IETF85 Atlanta 21 Copyright 2012 Juniper Networks, Inc.

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