Building interdom ain traffic engineering tools Steve UHLIG suh@ - - PowerPoint PPT Presentation

Building interdom ain traffic engineering tools

Steve UHLIG suh@ info.ucl.ac.be

http://www.info.ucl.ac.be/~suh/

Université catholique de Louvain, Belgium 1/12

Internet architectures W G, Cam bridge (M A), 26/1/05

Context

2/12

Internet architectures W G, Cam bridge (M A), 26/1/05

State-of-the-art

• Large-scale event-driven sim

ulators:

– SSFNet – JSim

• Route prediction:

– CBGP – RCP 3/12

Internet architectures W G, Cam bridge (M A), 26/1/05

CBGP

• An efficient open-source BGP sim

ulator written by Bruno Quoitin

• http://cbgp.info.ucl.ac.be
• Key features
• allows to m
• del large network topologies
• allows to reproduce BGP routing policies such as
• im

port and export filters, com m unities,...

• Perl and Python interfaces for interacting with CBGP
• Part of the TOTEM

TE toolbox (http://totem .info.ucl.ac.be)

4/12

Internet architectures W G, Cam bridge (M A), 26/1/05

CBGP config exam ple

5/12

Internet architectures W G, Cam bridge (M A), 26/1/05

TE over CBGP (1)

6/12

• TE tool collects

– IGP inform

ation for topology (e.g. pyrt)

– BGP routes (e.g. zebra) – Traffic statistics (e.g. netflow)

• TE tool

– changes IGP weights inside CBGP – injects eBGP update m

essages inside CBGP

– keeps traffic info up to date

Internet architectures W G, Cam bridge (M A), 26/1/05

TE over CBGP (2)

7/12

• Based on traffic engineering objectives, TE

tool determ ines the BGP route to be advertised to each border router via iBGP

– by sending different BGP UPDATEs for each im

portant prefix to each ingress routers, TE tool can influence the flow of the IP traffic

– ingress routers send transit traffic inside tunnels

(M PLS, GRE, ...) to egress routers or TE tool ensures consistency in IP forwarding if no tunnels are used

Internet architectures W G, Cam bridge (M A), 26/1/05

CBGP case studies

8/12

• Case studies perform

ed up to now:

– tweaking iBGP to lim

it im pact of peering failure on traffic m atrix

– assessing im

pact of internal link and router failures on best route choice inside the AS

– optim

izing (on-line) a cost function defined on

• utbound traffic of a stub AS

– com

putation of interdom ain M PLS LSPs in PCE's

Internet architectures W G, Cam bridge (M A), 26/1/05

Purpose of interdom ain TE ?

(for ISPs)

9/12

• reduce congestion
• reduce costs
• im

prove delays

• better load-balance traffic
• im

prove network robustness

• m

ake TM m

• re stable
• ...

Internet architectures W G, Cam bridge (M A), 26/1/05

Open questions

(for ISPs)

10/12

• Is congestion on peering links im

portant ?

• Do we need online or offline TE solutions ?
• Do we need to optim

ise for delay ?

• Do we need to optim

ise for bandwidth ?

• Is m

ultipath routing useful ?

• Do we need interdom

ain M PLS ?

• Do we need new policies ?

Internet architectures W G, Cam bridge (M A), 26/1/05

Open questions

(for ISPs)

11/12

• Do we need to quickly reroute in case of failures ?

If yes, how fast ?

• Billing issues ?
• W

hat about interdom ain QoS ?

Internet architectures W G, Cam bridge (M A), 26/1/05

Relevance of interdom ain TE

12/12

• Does som

eone really care about it ? or is it just about research ?

• Is interdom

ain TE aim ed at providing solutions to

• perational problem

s or just architectural guidelines ?

• Is interdom

ain TE relevant for interdom ain architecture at all ?

Internet architectures W G, Cam bridge (M A), 26/1/05