Future Routing and Addressing Models

Transcription

1 Future Routing and Addressing Models Rob Evans JANET(UK) The JNT Association 2008 Networkshop 36 1

2 If it ain't broke... BGP is the inter-domain protocol of choice. Not that there's much choice. Carries IPv4, IPv6, VPN, unicast, multicast routes. >250,000 routes in the global routing table. The JNT Association 2008 Networkshop 36 2

3 ...but maybe it is... Who noticed the YouTube outage? Some scope for improving security. Local policy decisions have global costs. Multihoming The JNT Association 2008 Networkshop 36 3

4 YouTube Outage. host has address has address has address The JNT Association 2008 Networkshop 36 4

5 YouTube Outage. JANET can't verify Cogent's or PCCW's customers. We have to assume they're telling us the truth. PCCW should know what to expect from its customers They should have been filtering. It all comes down to trust. The JNT Association 2008 Networkshop 36 5

6 Securing route origins Securing the whole path is hard. Instead, issue certificates to prove a given autonomous system can announce a certain bit of address space. If the origin of /22 (or anything more specific) isn't AS36561, ignore it. Or trust it less, details to be decided. The JNT Association 2008 Networkshop 36 6

7 That was just small fry... Certification of route announcements. Some people want to change the whole routing and addressing model of the Internet. The JNT Association 2008 Networkshop 36 7

8 Locators & Identifiers IP address is a... Locator Recursively follow it in routing tables for the packet to reach its destination. Identifier TCP session (for example) is bound to it. The JNT Association 2008 Networkshop 36 8

9 ID/Locator Split If identifiers and locators are split... Locators can relate to topology Increases aggregation One of BGP's main problems today is churn from lots and lots of multihomed sites. ID/Locator split can can get rid of this The JNT Association 2008 Networkshop 36 9

10 ID/Locator Split Methods Use part of the address for locator, part for identifier. Requires a large enough address (e.g. IPv6). GSE/8+8 from Mike O'Dell Network NAT Host identifier in bottom 64 bits of address Locator in top 64 bits, rewritten by border router. Six/One from Christian Vogt Not entirely unrelated to shim6 The JNT Association 2008 Networkshop 36 10

11 ID/Locator Split Methods Add an extra IP header. Map & Encap RFC1955, June 1996! Packet sent by end-host is unchanged Extra header for locator added by border router. Going to talk about this one, but just because it is generating the most noise at the moment... The JNT Association 2008 Networkshop 36 11

12 LISP Locator/ID Separation Protocol Yes, it is intentional Other parts of the protocol are called CONS, CAR, CDR... The JNT Association 2008 Networkshop 36 12

13 LISP Host in site A looks up a name in site B via DNS as usual. Address returned is an EID, e.g Sends packet as normal, source , destination Packet follows campus routing to the edge of the campus. The JNT Association 2008 Networkshop 36 13

14 LISP At ISP border, router looks destination ID up in a map. Routing Locators (RLOCs) are returned, addresses of destination ISP. E.g., lookup , get { , }. Extra IP header added, source IP is RLOC for site A, destination IP chosen from the map lookup. The JNT Association 2008 Networkshop 36 14

15 LISP Now we have a tunnelled packet. Inner source IP is Inner destination IP is Outer source IP is Outer destination IP is Router that does the encapsulation is called an Ingress Tunnel Router (ITR). The JNT Association 2008 Networkshop 36 15

16 What is the map? This is still a work in progress. Should it be: Fully pushed where it is needed? Partially pushed? Looked up on demand and cached? How do you look it up? DNS? New mechanism? Should routing depend on DNS? You see a lot of questions on this slide! The JNT Association 2008 Networkshop 36 16

17 LISP When packet gets to the ISP Z / Site B border ( ): Outer header is stripped off, the router that does this is called the Egress Tunnel Router (ETR). Site B's campus routing takes it to the final host. The JNT Association 2008 Networkshop 36 17

18 More questions. Who assigns identifiers? /4 used in this presentation. One potential use of the class E space. LISP provides mobility between ISPs, but you're stuck with your identity provider. Transition How do we gateway between the LISP world and the rest of the Internet? The JNT Association 2008 Networkshop 36 18

19 Why do all this? The global routing table now only consists of the routes to the RLOCs. These are all ISP address space, and so can be aggregated. Less churn, more reliable. The JNT Association 2008 Networkshop 36 19

20 When? LISP isn't the only solution... Six/One Ivip Internet Vastly Improved Plumbing Still some time away... The JNT Association 2008 Networkshop 36 20

21 What do I have to do? Nothing. Yet. Maybe. Some of the proposals, such as LISP, all happen in the routers. Still lots to change on a global scale. Some of them require changes to endhosts. As IPv6 has shown, there needs to be good transition mechanisms for these! The JNT Association 2008 Networkshop 36 21

22 Some Internet-Drafts draft-rrg-taxonomy-00.txt New! draft-vogt-rrg-six-one-01.txt draft-farinacci-lisp-06.txt Download drafts from: The JNT Association 2008 Networkshop 36 22