IP: Next GenerationA Tutorial Bruce A. Mah - PowerPoint PPT Presentation

IP: Next Generation—A Tutorial Bruce A. Mah bmah@{CS.Berkeley.EDU,research.ATT.COM} University of California at Berkeley International Computer Science Institute AT&T Bell Laboratories 29 August 1994 Y • O T I F S • R C A E V A L I I N F O U • R L E E L I G T H T N H T H I E R B E A T E • • • 1 8 • 8 6 IP: Next Generation—A Tutorial Page 1 of 29

Disclaimer I am not an IPng researcher. I don’t even play one on TV. IP: Next Generation— A T utorial Page 2 of 29

Outline Introduction IPng features Better header 128-bit address space Better options support Routing QOS support (sort of) IPv4 interoperability (Simple SIPP Transition) Current hot topics IP: Next Generation— A T utorial Page 3 of 29

Problems with the Internet Protocol IP address space exhaustion Routing table explosion Inefficient headers for high-speed networks Some features (e.g. source routing) not well supported New features needed (e.g. security) No QOS support IP: Next Generation— A T utorial Page 4 of 29

IP: Next Generation Replace IP with a new internetwork layer Retain the same basic philosophy, but try to solve IP’s problems Avoid changing other protocols (i.e. TCP, UDP) or applications (i.e. telnet ) where possible Need a transition plan Proposals SIPP (Simple Internet Protocol Plus) TUBA (TCP and UDP with Bigger Addresses) IP: Next Generation— A T utorial Page 5 of 29

Terminology IPv4 Internet Protocol, Version 4 SIP Simple Internet Protocol SIPP Simple Internet Protocol Plus SIPP-8 Original version, 64-bit addresses SIPP-16 Revised version, 128-bit addresses IPng IP: Next Generation IPv6 Internet Protocol, Version 6 IP: Next Generation— A T utorial Page 6 of 29

The IPv6 Header Version Flow Label Payload Length Next Header Hop Limit Source Address Destination Address IP: Next Generation— A T utorial Page 7 of 29

Changes from IPv4 Header Version Hdr Ln Prec TOS Total Length ID Flags Fragment Offset TTL Protocol Header Checksum Source Address Destination Address Fixed size header (no need for header length) Precedence/TOS handled with QOS and Flow Label TTL now a Hop Limit Fragmentation now an option Header protected by transport layer pseudo-header and checksums IP: Next Generation— A T utorial Page 8 of 29

Addressing Each address identifies an interface, possibly multiple addresses per interface Types of addresses distinguished by prefix Unicast Addresses IPv4 Provider-Based Geographic-Based (sort of, space reserved) NSAP IPX Local Use Cluster Addresses Multicast Addresses IP: Next Generation— A T utorial Page 9 of 29

IPv4 Compatable Addresses IPv4 0000........................................................................0000 IP Address IPv4 with IPv6 Support 0000.......................................................................FFFF IP Address Examples 0:0:0:0:0:FFFF:8020:C941 0:0:0:0:0:FFFF:128.32.201.65 ::FFFF:8020:C941 ::FFFF:128.32.201.65 IP: Next Generation— A T utorial Page 10 of 29

Provider-Based Unicast Addresses 01 Provider ID Subscriber ID Subnet Node Globally unique No fi xed fi eld boundaries Open issues How to easily reconfi gur e when switching providers? How to handle multi-homed hosts with multiple providers? IP: Next Generation— A T utorial Page 11 of 29

Local-Use Addresses 11111110 000......................00 Subnet ID Node ID Address scope limited to a single subscriber site Subnet ID used for routing Node ID can be an IEEE 802 address (for example) Applications Private internetworks (i.e. not attached to the Internet) Autoconfi guration and bootstrapping IP: Next Generation— A T utorial Page 12 of 29

Cluster Addresses Cluster Prefi x 0000..............................................0000 “Nearest” boundary router in a cluster of nodes Intended for use in source routing IP: Next Generation— A T utorial Page 13 of 29

Multicast Addresses 11111111 Flg Scp Group ID (112 Bits) Flags: Transient/Permanent Scope: Control extent of propagation Analagous to use of TTL for IPv4 multicast Group ID: Identifi es multicast gr oup Similar to IPv4 multicast groups No broadcast addresses, pre-defi ned gr oups used All Nodes All Hosts All Routers IP: Next Generation— A T utorial Page 14 of 29

DNS Modifi cations New ASEQ records contain IPv6 addresses (or sequences of addresses for source routed addreses) New sipp-addr.arpa domain for reverse name translation A records continue to hold IP addresses for IPv4-compatable hosts IP: Next Generation— A T utorial Page 15 of 29

IPv6 Options IPv6 Header (Next Header= Opt1) Opt1 Header (Next Header= Opt2) Opt2 Header (Next Header= TCP) TCP Header TCP Payload Options (usually) only examined at destination specifi ed in IPv6 header IP: Next Generation— A T utorial Page 16 of 29

IPv6 Options Hop-by-hop options (TLV format) Routing Fragmentation Authentication End-to-end (TLV format) IP: Next Generation— A T utorial Page 17 of 29

Routing Option Next Header Routing Type=0 Num. Addrs. Next Addr Reserved Address [0] .... Routing option processing off fast path Cluster addresses can be used to force routing through a given service provider or network SRDP has a similar routing option with Routing Type = 1 IP: Next Generation— A T utorial Page 18 of 29

Fragmentation Option Next Header Reserved Fragment Offset Res.M Datagram ID M bit: 1 = More Fragments Same functionality as IPv4 (datagram ID is bigger) Not a part of common-case processing but easy to detect at receiver Path MTU discovery algorithms mandatory ICMP messages now return next-hop MTU IP: Next Generation— A T utorial Page 19 of 29

Security Options SIPP Authentication Header Authentication and Integrity Assurance MD5 (128-bit key) recommended, other algorithms optional Want an exportable (outside USA) algorithm SIPP Security Encapsulation Protocol Authentication, Integrity, and Confi dentiality DES CBC proposed, other algorithms optional Open Issues Key Management? IP: Next Generation— A T utorial Page 20 of 29

Routing Very similar to IPv4 CIDR Routing lookup based on longest prefi x matches Relies on reasonable assignment of addresses for routing aggregation Common-case routing code only examines destination address in IPv6 header, regardless of routing headers IP: Next Generation— A T utorial Page 21 of 29

Source Routing Version Flow Label Payload Length Next = Routing Hop Limit Source Address = my:provider:my.net.subnet.host Destination Address = her:provider:0:0 Next = TCP Type = 0 Num Addrs = 2 Next Addr = 0 Reserved Address[0] = his:provider:0:0 Address[1] = your:provider:your.net.subnet.host IP: Next Generation— A T utorial Page 22 of 29

QOS Support TClass Flow ID Flow is defi ned by Flow ID (24 bits) and sour ce IPv6 address TClass = Traffi c Class Flow controlled vs. non-flow controlled “Priority” within flow controlled or non-flow controlled traffi c types Open issues: Resource model? Signalling to set up flows? IP: Next Generation— A T utorial Page 23 of 29

Simple SIPP Transition Goals Support IPv6 over IPv4 infrastructure Interoperability between IPv4 hosts and IPv6 hosts, where possible Operational requirements No “fl ag days” Gradual transition Uneven rates of IPv6 deployment Some hosts may never transition IP: Next Generation— A T utorial Page 24 of 29

SST Addressing Special IPv6 addresses for IPv4 compatability 0:0:0:0:0:0:128.32.201.65 (IPv4 only) 0:0:0:0:0:FFFF:128.32.201.65 (IPv4 and IPv6) A and ASEQ records in DNS servers Some interfaces may have multiple addresses IPv4 compatable, local to an IPv4 area IPv4 incompatable, presumed globally unique IP: Next Generation— A T utorial Page 25 of 29

SST Mechanisms Dual protocol stacks in hosts and routers Tunnelling via IPv4 encapsulation IPv6 IPv4 Only Cloud IPv6 Header Translation IPv4 Only Cloud Router IPv6 Only Cloud IP: Next Generation— A T utorial Page 26 of 29

SST Routing IPv4 to anything Route using normal IPv4 routing IPv6 to IPv6 If possible to send directly (same subnet) do so Else if there is an on-subnet IPv6 router, route via it Else if there is an off-subnet IPv6 router, tunnel to it Else tunnel to the destination IPv6 to IPv4 If a dual-stack machine, send as IPv4 Else, compute IPv6 address and send as to an IPv6 host IP: Next Generation— A T utorial Page 27 of 29

Topics Flambé Should the IPv6 address space be expanded to 20+ bytes to accomodate OSI NSAP addresses? Provider based addressing? Autor econfi guration Is it necessary? How to make it work? Authentication and source routing? IP: Next Generation— A T utorial Page 28 of 29

For More Information ipng mailing list Send mail to Majordomo@sunroof.eng.sun.com Body text subscribe ipng ftp://ds.internic.net/internet-drafts draft-ietf-sipp-spec-01.txt draft-ietf-sipp-routing-addr-02.txt draft-ietf-sipp-sst-overview-00.txt ftp://parcftp.xerox.com/pub/sipp SIPP archive http://town.hall.org Information and pointers to SIP/SIPP implementations IP: Next Generation— A T utorial Page 29 of 29