1Joint-techs Boulder © 2002, Cisco Systems, Inc. All rights reserved. Explicit Routing: the fish at 4+yrs Larry Dunn Manager, Advanced Architecture

22Joint-techs Boulder © 2002, Cisco Systems, Inc. All rights reserved. 2 Agenda Problem review Requirements Example topology General architecture/solution classes Example: Early binding Example: Late binding Invitation: routing working group

33Joint-techs Boulder © 2002, Cisco Systems, Inc. All rights reserved. 3 Problem review: “This old fish…” R8 R2 R6 R3 R4 R7 R5 R1 Flows from R8 and R1 Merge at R2 and Become Indistinguishable From R2, Traffic to R3, R4, R5 Use Upper Route Alternate Path may be required “by policy” for R1

44Joint-techs Boulder © 2002, Cisco Systems, Inc. All rights reserved. 4 Requirements Accommodate >1 class of traffic (e.g., Abilene- eligible, vs. not-eligible). Some have more classes (e.g., carrier selection). Amounts to overriding “normal IP routing” somewhere in the network Evaluation metrics: robustness/fragility, performance, complexity(for humans and routers), scalability, $$

55Joint-techs Boulder © 2002, Cisco Systems, Inc. All rights reserved. 5 Example topology School-D-eligible School-B-ineligible Destination School-E Abilene School-A-eligible Commodity ISP1 School-C-ineligible Gigapop Commodity ISP2

66Joint-techs Boulder © 2002, Cisco Systems, Inc. All rights reserved. 6 General Architecture Classes “Early binding” Decision made close(r) to the source Decision must be conveyed to the gigapop (VC, Label, DLCI, tunnel, TOS-overload, etc.) “Late binding” Gigapop router does multi-field classification (typically source-prefix) Everybody else just does “regular forwarding”

77Joint-techs Boulder © 2002, Cisco Systems, Inc. All rights reserved. 7 Example: Early binding #1: MPLS/VPNs School-A-eligible Commodity ISP1 School-C-ineligible Abilene Gigapop Commodity ISP2 School-D-eligible School-B-ineligible (tunnel FIB) (eligible, non-tunnel FIB, includes Abilene)

88Joint-techs Boulder © 2002, Cisco Systems, Inc. All rights reserved. 8 Ex: Early binding #2: generalized tunnels School-A-eligible Commodity ISP1 School-C-ineligible Abilene Gigapop Commodity ISP2 School-D-eligible School-B-ineligible (normal FIB for ineligible) (three trivial entries, one per ISP) Route server BGP to dist. routes; schools choose w/in policy, use tunnel(GRE, FR, MPLS, whatever) to deliver pkts to trivial FIBs. Ineligible schools just do “normal routing”.

99Joint-techs Boulder © 2002, Cisco Systems, Inc. All rights reserved. 9 Example: Late binding (at gigapop) School-A-eligible Commodity ISP1 School-C-ineligible Abilene Gigapop Commodity ISP2 School-D-eligible School-B-ineligible (ineligible FIB) (eligible FIB, includes Abilene) Schools do “normal routing”, gigapop router uses multi-field classification (typ. Src-prefix) to choose routing table

10 Joint-techs Boulder © 2002, Cisco Systems, Inc. All rights reserved. 10 Invitation: routing working group Today, 5:00pm..7:45p(max), at conf. hotel Merit folks’ routing registry discussion Deeper discussion of architectural options Your thoughts/ideas (see yourself here?) More detailed presos from {Juniper,Cisco} (implementation, customer feedback, etc.)

11 Joint-techs Boulder © 2002, Cisco Systems, Inc. All rights reserved. 11 Summary Fish problem: been around a long time Early solutions: multiple boxes, ATM Today: better understanding of possible architectures; getting field experience Advice: use the least complicated mechanism that will work for your environment ;-)

12 © 2001, Cisco Systems, Inc. All rights reserved. QoS Update

13 Joint-techs Boulder © 2002, Cisco Systems, Inc. All rights reserved. 13 Routing w.g. Architecture follow-up Taxonomy/solution families Early binding: policy,security, other facets Late binding: policy, security Open discussion

14 Joint-techs Boulder © 2002, Cisco Systems, Inc. All rights reserved. 14 Taxonomy/solution_families Generalized tunnels MPLS/VPNs TOS_overload Port-based Src-addr/5-tuple/else Early binding Late binding Notes: 1. Single-box, multiple-box decision is orthogonal 2. Combinations are possible/expected 3. Often, the “early-binding” solutions look like a distributed version of late-binding (Normal IP routing)

15 Joint-techs Boulder © 2002, Cisco Systems, Inc. All rights reserved. 15 Early binding (gen. tunnels): policy, security, other facets School-A-eligible Commodity ISP1 School-C-ineligible Abilene Gigapop Commodity ISP2 School-D-eligible School-B-ineligible (normal FIB for ineligible) (three trivial entries, one per ISP) Route server BGP to dist. routes; schools choose w/in policy, use tunnel(GRE, FR, MPLS, whatever) to deliver pkts to trivial FIBs. Ineligible schools just do “normal routing”. Note: carried to extreme, gigapop starts to feel like an (indirect) L2-exchange

16 Joint-techs Boulder © 2002, Cisco Systems, Inc. All rights reserved. 16 Late binding: policy, security School-A-eligible Commodity ISP1 School-C-ineligible Abilene Gigapop Commodity ISP2 School-D-eligible School-B-ineligible (ineligible FIB) (eligible FIB, includes Abilene) Schools do “normal routing”, gigapop router uses multi-field classification (typ. Src-prefix) to choose routing table

17 Joint-techs Boulder © 2002, Cisco Systems, Inc. All rights reserved. 17 Open discussion Is issue significant to you? Timeframe? Implementation stories? Your topology/complexity? Other useful models/hybrids?